Lagunas Mediterraneas Temporales

Mediterranean Temporary Pools Volume 1 – Issues relating to conservation, functioning and management Grillas P., P. Gauthier, N. Yavercovski & C. Perennou

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Production: Station biologique de la Tour du Valat Design: Tapages Publics Illustrations: Sonia Viterbi Translated from French by Janet Clayton and John Phillips Cover: photos Jean Roché (above) and Dominique Rombaut (right)

© 2004 Station biologique de la Tour du Valat Le Sambuc - 13200 Arles - France Readers are invited to reproduce texts and illustrations featured in this publication provided credit is given to the authors and to the Station Biologique de la Tour du Valat. All photos rights reserved. No photographic part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying except as may be expressly permitted in writing from the publisher. ISBN : 2-9103-6850-5

The LIFE “Temporary Pools” project The LIFE “Temporary Pools” project took place during the period 1999-2004. Its main objectives were to achieve the integrated management of seven sites in Mediterranean France and to develop management tools and methods for these fragile habitats which could be transferred to the Mediterranean scale. The project was organised into seven site sections (cf. map) and two overarching theme-based sections “Awareness raising” and “Integrated management”). The Tour du Valat was in charge of the “Integrated management” section as well as the general coordination of the project. The other sections were delegated to six local operators. The cost of the project was around 1,000,000 €, of which 50% was financed by the EU and the rest by 12 or so partners. Partners European Commission, Ministère de l’Ecologie et du Développement Durable (MEDD) and its Directions régionales de l'environnement (PACA, Languedoc-Roussillon and Corsica), LanguedocRoussillon region (Agence Méditerranéenne de l’Environnement), Corsica region (Office de l’Environnement de Corse), ProvenceAlpes-Côte d’Azur region (Agence Régionale pour l’Environnement: ARPE), Agence de L’Eau Rhône-Méditerranée-Corse, Conservatoire de l’Espace Littoral et des Rivages Lacustres, Conservatoire Botanique National de Porquerolles, Conservatoire des Espaces Naturels Languedoc-Roussillon, Conservatoire Etude des Ecosystèmes de Provence Alpes du Sud (CEEP), Association de Défense de la Nature des Pays d’Agde (ADENA), Association de Gestion de la Réserve Naturelle de Roque-Haute, Ecosphère, Institut Méditerranéen d'Ecologie et de Paléoécologie (Université d'Aix-Marseille III), Ecole Pratique des Hautes Etudes (EPHE), Départements du Gard et de l’Hérault, Office National des Forêts (Gard and Var).

Map of LIFE Programme Temporary Pool sites

Provence-Alpes-Côte d’Azur

LanguedocRoussillon Mediterranean Sea

Corsica C1: Padulu Languedoc-Roussillon L1: Etang de Valliguières L2: Notre-Dame de l’Agenouillade L3: Roque-Haute

Achievements The project’s activities covered six major areas: The furthering of knowledge and the drawing-up of management plans Inventories of the fauna, flora and human activities were made at most of the sites as well as more detailed studies of the species or locally important themes: perception of the pools by users and local players, a detailed inventory of the cupular micro-pools, monitoring of threatened species, etc. The results of these studies served as the basis for measures proposed in the management plans drawn up for three of the sites. Finally, an initial inventory of the temporary pools in Mediterranean France was carried out, enabling over 100 sites supporting almost 1000 pools to be identified. Control over land ownership and land use Control over land use by organisations for the protection of natural habitats is an essential prerequisite for any management of temporary pools. In total, over 83 hectares were acquired within the framework of the project. In addition, management agreements were made with owners (private or communal) on at least two sites, significantly increasing the area for which usage can be controlled in the mid term. Management work Experimental management work took place on most of the sites: Scrub clearing, cleaning out, digging-out of a pool, pulling up invasive exotic species, restoration of a filled-in pool, etc. Most of this work was accompanied by careful monitoring of its impact, in order to draw lessons that could be transposed elsewhere. Raising awareness The various site teams regularly interacted with and provided regular information to local inhabitants, elected political representatives and users. Numerous awareness-raising, communication and environmental education initiatives took place: European “Green Days”, events for schools, leaflets, information panels, web pages, posters, educational module, press articles, TV programme, video cassette, etc. Local events were organised to encourage local inhabitants to protect the temporary pools. On the global scale, a resolution calling for the conservation of temporary pools was drawn up by the project and adopted at the eighth Ramsar Conference in November 2002. Integrated management This section provided the framework for discussion prior to all the management work undertaken. It also allowed permanent exchanges to take place between the managers of sites and the scientists involved in the project: exchange visits between sites, theme-based workshops, coordination of the network, etc. Finally, this management handbook was published. A final international conference was also organised, bringing together almost 100 participants from all over Europe and the Mediterranean region.

Corsica

Provence-Alpes-Côte d’Azur P1: Besse et Flassans P2: Colle du Rouet P3: Plaine des Maures

Coordination Permanent coordination between all these various activities and partners was organised throughout the project. A steering committee was set up and meetings organised, regular contacts were maintained with the European Commission and all the partners in the project.

The operators and partners of the LIFE-Nature projet “Conservation of Mediterranean Temporary Pools” n° 99/72049 The operators ADENA: Association de Défense de la Nature des Pays d’Agde Domaine du grand Clavelet, F-34300 Agde, France Tél.: +33 (0)4 67 01 60 23, fax: +33 (0)4 67 01 60 29 [email protected]

Commune de Flassans-sur-Issole Hôtel de ville, avenue du Général de Gaulle, F-83340 Flassans-sur-Issole Tél: +33 (0)4 94 37 00 50, fax: +33 (0)4 94 69 78 99 Commune du Muy Hôtel de Ville, 4, rue Hôtel de Ville, F-83490 Le Muy Tél.: +33 (0)4 94 19 84 24, fax: +33 (0)4 94 19 84 39

AGRN.RH: Association de Gestion de la Réserve Naturelle de Roque-Haute 1, rue de la Tour, F-34420 Portiragnes, France Tél. / fax: +33 (0)4 67 90 81 16 [email protected]

Commune de Portiragnes Hôtel de Ville, avenue Jean Moulin, F-34420 Portiragnes Tél.: + 33 (0)4 67 90 94 44, fax: +33(0)4 67 90 87 00

CEEP: Conservatoire Etudes des Ecosystèmes de Provence Alpes du Sud 890, chemin de Bouenhoure Haut, F-13090 Aix-en-Provence Tél.: +33 (0)4 90 47 02 01, fax: +33 (0)4 90 47 05 28 [email protected]

Commune de Vias Hôtel de Ville, 6, place des Arènes, F-34450 Vias Tél.: +33 (0)4 67 21 66 65, fax: +33 (0)4 67 21 52 21

2. CEEP Var 1, place de la Convention, F-83340 Le Luc Tél: +33 (0)4 94 50 38 39, fax: 04 94 73 36 86 CEN-LR: Conservatoire des Espaces Naturels du Languedoc-Roussillon 20, rue de la République, Espace République, F-34000 Montpellier Tél.: +33 (0)4 67 22 68 28, fax: +33 (0)4 67 22 68 27 [email protected] OEC: Office de l'Environnement de la Corse Avenue Jean Nicoli, F-20250 Corte Tél.: +33 (0)4 95 45 04 00, fax: +33 (0)4 95 45 04 01 TDV: Station Biologique de la Tour du Valat Le Sambuc, F-13200 Arles Tél.: +33 (0)4 90 97 20 13, fax: +33 (0)4 90 97 20 19 [email protected], web site: www.tourdu valat.org

Commune de Valliguières Mairie de Valliguières, F-30210 Valliguières Tél.: +33 (0)4 66 37 18 64, fax: +33 (0)4 66 37 36 45 Conseil Général du Gard Hôtel du Département, rue Guillemette, F-30044 Nîmes cedex 9 Tél.: +33 (0)4 66 76 76 76 Conseil Général de l’Hérault Hôtel du Département, 1 000, rue d’Alco, F-34087 Montpellier cedex 4 Tél.: +33 (0)4 67 67 67 67, fax: + 33 (0)4 67 67 76 41 Conseil Régional du Languedoc-Roussillon Hôtel de Région, 201, avenue de la Pompignane, F-34064 Montpellier cedex 2 Tél.: +33 (0)4 67 22 80 00, fax: +33 (0)4 67 22 81 92 Conseil Régional de Provence-Alpes-Côte-d’Azur Hôtel de Région, 27, place Jules Guesde, F-13481 Marseille cedex 20 Tél.: +33 (0)4 42 90 90 90, web site: www.cr-paca.fr

The partners AME: Agence Méditerranéenne de l’Environnement Espace littoral de l’Hôtel de Région, 417, rue Samuel Morse, F-34000 Montpellier Tél.: +33 (0)4 67 22 94 05, fax: +33 (0)4 67 22 94 05 [email protected]

DIREN LR: Direction Régionale de l’Environnement du LanguedocRoussillon 58, avenue Marie de Montpellier, CS 79034, F-34965 Montpellier cedex 2 Tél.: +33 (0)4 67 15 41 41, fax: +33 (0)4 67 15 41 15 pré[email protected]

ARPE: Agence Régionale Pour l'Environnement PACA Parc de la Duranne, avenue Léon Foucault, immeuble Le Levant BP 432000, F-13591 Aix-en-Provence Cedex 03 Tél.: +33 (0)4 42 90 90 90, fax: +33 (0)4 42 90 90 91

DIREN PACA: Direction Régionale de l’Environnement de PACA Le Tholonet, BP 120, F-13603 Aix-en-Provence cedex 1 Tél.: +33 (0)4 42 66 66 00, fax: +33 (0)4 42 66 66 01 pré[email protected]

Agence de l’Eau RMC: Agence de l’Eau Rhône-Méditerranéee et Corse Direction de la Planification et de la Programmation, Unité Planification, 2-4, allée de Lodz, F-69363 Lyon Cedex 07 Tél.: +33 (0)4 72 71 26 00, fax: +33 (0)4 72 71 26 03

DIREN Corse: Direction Régionale de l’Environnement de Corse Route d’Agliani, Montesoro, F-20600 Bastia Tél.: +33 (0)4 95 30 13 70, fax: +33 (0)4 95 30 13 89 pré[email protected]

CBNMP: Conservatoire botanique national méditerranéeen de Porquerolles Castel Sainte-Claire, F-83418 Hyères cedex Tél: +33 (0)4 94 12 82 30, fax: +33 (0)4 94 12 82 31 [email protected]

Ecosphère 3 bis, rue des remises, F-94100 Saint-Maur-des-Fossés Tél.: +33 (0)1 45 11 24 30, fax: +33 (0)1 45 11 24 37 [email protected]

2. Antenne du Languedoc-Roussillon Institut de Botanique, rue Auguste Broussonet, F-34090 Montpellier Tél.: +33 (0)4 99 23 22 11, fax: +33 (0)4 99 23 22 12 [email protected]

EPHE: Ecole pratique des hautes études Laboratoire de Biogéographie et Ecologie des vertébrés, Case 94 Université de Montpellier II, place E. Bataillon, F-34095 Montpellier cedex 5 Tél.: +33 (0)4 67 14 32 90, fax: +33 (0)4 67 63 33 27

CELRL: Conservatoire de l’Espace Littoral et des Rivages Lacustres 1. Délégation Languedoc-Roussillon 165, rue Paul Rimbaud, F-34184 Montpellier Cedex 4 Tél.: +33 (0)4 99 23 29 00, fax: +33 (0)4 99 23 29 09 [email protected]

MEDD: Ministère de l’Ecologie et du Développement Durable Direction de la Nature et des paysages, 20, av. de Ségur, F-75302 Paris 07 SP Tél.: +33 (0)1 42 19 20 21, web site: www.environnement.gouv.fr

2. Délégation PACA 3, rue Marcel Arnaud, F-13100 Aix-en-Provence Tél.: +33 (0)4.42.91.64.10, fax: +33 (0)4.42.91.64.11 [email protected] Collectivité territoriale de Corse 22, cours Grandval, BP 215, F-20187 Ajaccio cedex Tél.: +33 (0)4 95 51 64 64 Communauté d'Agglomération Hérault Méditerranée ZI le Causse, BP 26, F-34630 Saint-Thibéry Tél.: +33 (0)4 99 47 48 49, fax: +33 (0)4 99 47 48 50 Commission Européenne DG ENV D1, BU 9 02/1, 200 Rue de la loi, B-1049 Bruxelles Commune de Besse-sur-Issole Hôtel de ville, place Noël Blache, F-83890 Besse-sur-Issole Tél.: +33 (0)4 94 69 70 04, fax: +33 (0)4 94 59 65 57 Commune du Cannet des Maures Hôtel de Ville, place de la Libération, F-83340 Le Cannet-des-Maures Tél.: +33 (0)4 94 50 06 00, fax: +33 (0)4 94 73 49 61

ONF Var: Office National des forêts, Agence Départementale du Var Unité Spécialisée Développement, (A.D. O.N.F. 83) 101, chemin de San Peyre, F-83220 le Pradet Tel: +33 (0)4 98 01 32 50, fax: +33 (0)4 94 21 18 75 [email protected] ONF Gard: Office National des Forêts, Agence Départementale du Gard 1, impasse d’Alicante, BP 4033, F-30001 Nîmes Cedex 5 Tél.: +33 (0)4 66 04 79 00, fax: +33 (0)4 66 38 99 69 [email protected] Université d’Aix Marseille III – IMEP Institut Méditerranéen d'Ecologie et de Paléoécologie - CNRS UMR 6116 Université d'Aix-Marseille III Europole méditerranéen de l'Arbois, bâtiment Villemin, BP 80 F-13545 Aix-en-Provence cedex 04, France Tél.: +33 (0)4 42 90 84 06, fax +33 (0)4 42 90 84 48 Pole-relais "Mares et Mouillères de France" Institut Européen du Développement Durable, Centre de BiogéographieEcologie 66, rue de France, 77300 Fontainebleau Tél.: +33 (0)1 60 72 19 61, fax: +33 (0)1 60 72 08 46 [email protected]

Mediterranean Temporary Pools volume 1 Issues relating to conservation, functioning and management

Editors: Grillas P., P. Gauthier, N. Yavercovski & C. Perennou Associate editors: Thiéry A., M. Cheylan, C. Jakob, F. Médail, G. Paradis, L. Rhazi, F. Boillot & F. Ruchon

Editors, associate editors, authors and collaborators Besnard A. (EPHE), Boillot F. (CBNMP), Boutin J. (CEEP1), Catard A. (CEEP2), Chauvelon P. (TDV), Cheylan M. (EPHE), Duborper E. (TDV), Emblanch C. (université d’Avignon), Félisiak D. (TDV), Gauthier P. (TDV), Genthon S. (AGRN.RH), Grillas P. (TDV), Hébrard J. P. (université d’Aix-Marseille III – IMEP1), Heurteaux P. (CNRS ad., perso. 1), Hugonnot V. (ad. perso. 2), Jakob C. (EPHE et TDV), Lombardini K. (EPHE), Marsol L. (ONF Var), Martin C. (université d’Avignon), Médail F. (université d’Aix-Marseille III – IMEP2), Paradis G. (université de Corse, ad. perso. 3), Perennou C. (TDV), Pichaud, M. (TDV), Quézel P. (université d’Aix-Marseille III – IMEP, ad. perso. 4), Rhazi L. (université Hassan II), Rhazi M. (TDV, université d’Aix-Marseille III – IMEP2), Rombaut D. (CEEP2), Ruchon F. (AGRN-RH), Samraoui B. (université d’Annaba), Scher O. (université de Provence, Aix-Marseille I), SouliéMärsche I. (université Montpellier II), Thiéry A. (université de Provence, AixMarseille I) and Yavercovski N. (TDV)

Université de Provence, Aix-Marseille I (Scher O., Thiéry A) E.A. Biodiversité et environnement, Université de Provence, 3, place Victor Hugo, F-13331 Marseille cedex 3 Tél: +33 (0)4 91 10 64 25, fax: 04 91 10 63 03 [email protected]

AGRN.RH (Genthon S., Ruchon F.) Association de Gestion de la Réserve Naturelle de Roque-Haute, 1, rue de la Tour, F-34420 Portiragnes Tél/fax: +33 (0)4 67 90 81 16 [email protected]

Université de Montpellier II (Soulié-Märsche I.) Laboratoire de Paléobotanique - UMR 5554 du CNRS, Université Montpellier II, C.P. 062, Place E. Bataillon, F-34095 Montpellier cedex 5 Tél: +33 (0)4 67 14 39 78, fax: +33 (0)4 67 14 30 31 [email protected]

CBNMP (Boillot F.) Conservatoire botanique national de Porquerolles, Castel Sainte Claire, F-83418 Hyères cedex Tél: +33 (0)4 94 12 82 30, fax: +33 (0)4 94 12 82 31 [email protected]

Université d’Annaba (Samraoui B.) Laboratoire de recherche des zones humides, Université d’Annaba, 4, rue Hassi-Beïda, Annaba, Algérie [email protected]

CEEP1 (Boutin J.) Conservatoire Études des Écosystèmes de Provence Alpes du Sud, 890, chemin de Bouenhoure Haut, F-13090 Aix en Provence Tél: +33 (0)4 90 47 02 01, fax: +33 (0)4 90 47 05 28 [email protected] CEEP2 (Catard A., Rombaut D.) Conservatoire Études des Écosystèmes de Provence Alpes du Sud-Var, 1, place de la Convention, F-83340 Le Luc Tél: +33 (0)4 94 50 38 39 / 06 16 97 82 03 [email protected] [email protected] EPHE (Besnard A., Cheylan M., Jakob C., Lombardini K.) Ecole pratique des hautes études, Laboratoire de Biogéographie et Ecologie des vertébrés, Case 94, Université de Montpellier II, Place E. Bataillon, F-34095 Montpellier cedex 5 Tel: +33 (0)4 67 14 32 90 [email protected] [email protected] [email protected] ONF Var (Marsol L.) Unité Spécialisée Développement / Agence Départementale du Var de l'Office National des Forêts (AD ONF 83), 101, chemin de San Peyre, F-83220 le Pradet Tél: +33 (0)4 98 01 32 50, ligne directe: +33 (0)4 98 01 32 78, fax: +33 (0)4 94 21 18 75 [email protected] / [email protected] TDV (Chauvelon P., Duborper E., Félisiak D., Gauthier P., Grillas P, Jakob C., Perennou C., Pichaud M., Rhazi M., Yavercovski N.) Station Biologique de la Tour du Valat, Le Sambuc, F-13200 Arles Tél: +33 (0)4 90 97 20 13, fax: +33 (0)4 90 97 20 19 [email protected] Université d’Aix-Marseille III – IMEP1 (Hébrard J.P.) Institut Méditerranéen d'Ecologie et de Paléoécologie - CNRS UMR 6116, Université d'Aix-Marseille III, Faculté des Sciences et Techniques de Saint-Jérôme, Case 461, F-13397 Marseille cedex 20 Tél: +33 (0)4 91 28 85 35, fax: +33 (0)4 91 28 80 51 Université d’Aix Marseille III – IMEP2 (Médail F., Rhazi M.) Institut Méditerranéen d'Ecologie et de Paléoécologie - CNRS UMR 6116, Université d'Aix-Marseille III, Europole méditerranéen de l'Arbois, bâtiment Villemin, BP 80, F-13545 Aix-en-Provence cedex 04 Tél: +33 (0)4 42 90 84 06, fax: +33 (0)4 42 90 84 48 [email protected]

Université d’Avignon1 (Emblanch C.) Laboratoire d’Hydrogéologie, Université d’Avignon et des pays de Vaucluse, F-84000 Avignon [email protected] Université d’Avignon (Martin C.) Laboratoire de Biologie, Université d’Avignon et des pays de Vaucluse, F-84000 Avignon [email protected]

Université Hassan II (Rhazi L.) Faculté des Sciences Aïn Chock, Laboratoire de Biologie et Physiologie Végétale, BP 5366, Maarif Casablanca, Maroc Tél.: (212) 037 86 33 10, fax: (212) 022 23 06 74 [email protected] ad. perso. 1 (Heurteaux P.) 24, rue Pierre Renaudel, F-13200 Arles Tél: +33 (0)4 90 52 09 00, fax: +33 (0)4 90 52 08 99 [email protected] ad. perso. 2 (Hugonnot V.) Le Bourg, F-43270 Varennes Saint Honorat Tél/Fax: +33 (0)4 71 00 23 07 [email protected] ad. perso. 3 (Paradis G.) 7, cours Général Leclerc, F-20000 Ajaccio Tél: +33 (0)4 95 50 11 65 [email protected] ad. perso. 4 (Quézel P.) Chemin du Cabrol, F-13360 Roquevaire [email protected] Acknowledgments The Station biologique de la Tour du Valat would like to warmly thank all the editors, authors and everyone who collaborated on this volume, as well as Mohand Achérar (CEN-LR), Joël Bourideys (DIREN PACA), Christine Bousquet (AME), Jean Boutin (CEEP), Thomas Calvière (TDV), Maddy Cancemy (OEC), Marie-Luce Castelli (OEC), Paul Chemin (DIREN LR), Claire Chevin (MEDD), Béatrice Coisman (CEEP), Natacha Cotinaut (Mairie du Cannet-des-Maures), Geneviève Coutrot (TDV), Daniel Crépin (DIREN LR), Florence Daubigney (TDV), Christian Desplats (CELRL PACA), Aude Doumenge (AGRN-RH), Renaud Dupuy de la Grandrive (ADENA), Roger Estève (CELRL PACA), Sabine Fabre (CEN-LR), Mauricette Figarella (DIREN Corse), Guy-François Frisoni (Réserve Naturelle des Bouches de Bonifacio), Jérôme Fuselier (ADENA), Stéphanie Garnéro (CEN-LR), Jean Giudicelli (Maison régionale de l’eau, Barjols), Denis Gynouvès (ONF Var), Jean-Claude Heidet (CEEP), Claudie Houssard (CEN-LR), Bruno Julien (Commission Européenne), Emilio Laguna (Generalitat de Valence, Espagne), Olivier Limoges (Pôle relais Mares et Mouillères), Stéphanie Lieberherr (CEEP Var), Gilles Loliot (CELRL Languedoc-Roussillon), Isabelle Lourenço de Faria (Commission Européenne), Margarida Machado (Université d’Algarve, Portugal), Marc Maury (Ecosphère), Leopoldo Medina, Olivier Nalbone (ARPE), Georges Olivari (Maison régionale de l’eau, Barjols), Eric Parent (Agence de l’Eau RMC), Jean-Claude Pic (TDV), Marlène Savelli (OEC), Pierre Quertier (ONF Var), Bertrand Sajaloli (Pôle relais Mares et Mouillères), Nathalie Saur (Agence de l’Eau RMC), Alain Sandoz (TDV), Hassan Souheil (AGRN-RH), Laurine Tan Ham (TDV), Florence Verdier (CELRL LR) and Myriam Virevaire (CNBMP) for their contribution to the LIFE “Temporary Pools” project.

Preface Temporary pools are without doubt some of the most remarkable yet most threatened habitats in the Mediterranean region. They comprise an ensemble of highly complex biotopes linked to the major characteristics of the Mediterranean climate: the alternation, during the course of a year, of one or more flooded phases during the cooler seasons with a dry phase, essentially in the summer. It is in this mosaic of habitats that highly specific, long-established and often residual plant and animal populations have become differentiated. Various biological groups - mainly plants but also crustaceans and batrachians - have individualised ensembles of particular genera and species here; others, meanwhile, have developed only commonplace or generalist* species. Some of these groups – such as the microarthropods or the arachnids – remain practically unknown, while others, such as the phyllopods, have recently benefited from detailed taxonomic analysis. For over two centuries now, botanists have been interested in the higher plants and the bryophytes*. They have also evidenced, in the vegetation component of these pools, the remarkable analogies existing between the communities of the various Mediterranean regions, thus highlighting the extreme length of time during which many of the genera have been present, especially the vascular cryptograms Isoetes, Marsilea and Pilularia. The adaptive strategies put in place by a number of temporary-pool species to ensure their survival are often remarkable and complex. From this point of view, these habitats are ideal material for analysing the impact of drastic ecological conditions on the adaptive or ecological processes occurring in populations which are often reduced and whose habitat is extremely fragmented. Awareness of the major biological interest of Mediterranean temporary pools is recent and unfortunately only too frequently linked with their progressive destruction: for a long time considered as mere curiosities, they now belong to the priority habitats of the European Union. The increasing degradation, generally anthropogenic in origin, which affect these habitats has resulted in drastic perturbations or even disappearances, such as at the pools of Grammont, Saint-Estève or Biot in southern France for example. In these conditions, a comprehensive approach, from the inventory to the drawing-up of a methodology for the management and restoration of Mediterranean temporary pools, has proved to be vital. It should take into account the updating of inventories, especially for groups still insufficiently known, and the analysis of all the kinds of threats currently weighing on these biotopes. This process should result in medium and long-term monitoring programmes as well as in the awareness-raising of the public and decision-makers (local authorities, public services, management organisations, etc.) regarding the exceptional natural-heritage and biological interest of these habitats. It was with this aim in mind that the LIFE European programme was launched in 1999. It has culminated today in this “management handbook” which, for the first time, draws up the balance sheet, analyses the impact of the threats facing these habitats and puts forward a number of measures to ensure their conservation in the medium and long term.

Quézel P.

Summary 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

5. Management and restoration methods . . . . . . . . . . . . . . . 69 a. From site assessment to management plan . . . . . . . . 69

2. Biodiversity and conservation issues. . . . . . . . . . . . . . . . . . 11

b. Land management and uses . . . . . . . . . . . . . . . . . . . . 76

a. Habitats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

c. Management of habitats and populations . . . . . . . . . 79

b. Plant species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 c. Amphibians . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6. Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

d. Macrocrustaceans . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

a. Why and how to conduct monitoring . . . . . . . . . . . . . 88

e. Insects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

b. Hydrological monitoring . . . . . . . . . . . . . . . . . . . . . . . . 90 c. Vegetation monitoring . . . . . . . . . . . . . . . . . . . . . . . . . 94

3. Ecosystem and population functioning and dynamics . . . . 34

d. Amphibian monitoring . . . . . . . . . . . . . . . . . . . . . . . . . 98

a. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

e. Crustacean monitoring . . . . . . . . . . . . . . . . . . . . . . . . 102

b. Hydro-climatic characteristics . . . . . . . . . . . . . . . . . . . 35

f. Insect monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

c. Vegetation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 d. Amphibians . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

7. Education and communication . . . . . . . . . . . . . . . . . . . . . . 105

e. Invertebrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 f. Population dynamics and genetics . . . . . . . . . . . . . . . . . 52

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

4. Threats to Mediterranean temporary pools . . . . . . . . . . . . 61

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Introduction Grillas P.

Introduction Temporary pools are unusual habitats, neither truly aquatic nor truly terrestrial, where alternating phases of flooding and drying out, as well as their isolation, favour the establishment of unique and diverse plant and animal communities (Box 1). These habitats are characteristic of climatic conditions typified by long dry seasons, in the Mediterranean region and also in various parts of the world subject to more or less arid climates: Mediterranean and arid climatic regions of North and South Africa, the Americas (USA, Chile) and Australia. Mediterranean temporary pools are very variable in size, from the large pools of Provence or the dayas of North Africa (several hectares) to cupular pools a few tens of centimetres square on rocky substrates (Provence, Sicily, Malta), via isolated pools of a few hundred square metres.

Rich and varied habitats Temporary pools have a number of ecological characteristics in common. However, they do not constitute a homogenous group and they vary considerably depending on the biogeographical and climatic region (see next chapter). The hydrological regime, soil type, nature of the underlying rocks and physicochemical characteristics of the water play a major role in their ecology. In these habitats, subjected to extreme and unstable ecological conditions, often isolated and continually alternating between the aquatic and the terrestrial environments, the flora has developed remarkable adaptations for survival: a wide range of different sizes, growth forms, modes of reproduction and life-history strategies (Chapter 3). The fauna has also had to adapt to the same constraints, with the result that these habitats support a diverse genetic heritage of great value: there are many rare species here and many have unique ways of life. Hence, amphibians constitute a very important group in Mediterranean temporary pools, with many rare or localised species (Chapter 2c). Several

Box 1. The Ramsar definition of temporary pools16 Temporary pools are small (generally <10 ha), shallow wetlands characterised by alternating phases of drought and flooding and by very self-contained hydrology. They occur in depressions, which are often endorheic*, that are submerged for sufficiently long periods of time to allow the development of hydromorphic soils, aquatic or semi-aquatic vegetation, and specific animal communities. However, and equally importantly, they dry out for long enough to exclude the more commonplace plant and animal communities which are characteristic of more permanent wetlands. This definition specifically excludes habitats that are in direct physical contact with permanent water bodies (fringes of lakes, permanent marshes, large rivers, etc.), which generally do not allow the most characteristic species of these habitats to develop.

Box 2. Mediterranean temporary pools15 Temporary, very shallow water bodies (a few centimetres deep) existing only in winter or at the end of spring, with a semiaquatic Mediterranean vegetation consisting of therophytes* and geophytes* belonging to the Isoetion, Nanocyperion flavescentis, Preslion cervinae, Agrostion salmanticae, Heleochloion and Lythrion tribracteati alliances. invertebrate groups such as phyllopod crustaceans (Chapter 2d) and some insects (Chapter 2e) are characteristic of temporary pools and are particularly well adapted to the alternating dry and flooded phases. Regarding temporary wetlands, the European Union Directive 92/43/EEC of 21 May 1992 (known as the “Habitats Directive”118), limits the Mediterranean Temporary Pools category to two main types of habitat (Box 2) which are given priority: exclusively freshwater* habitats on non-calcareous substrates, and habitats on slightly brackish substrates that are often calcareous. Mediterranean temporary pools on non-calcareous substrates are characterised by their floristic richness and have earned the description “floristic gems”54. They are found in the five regions of the world with a Mediterranean climate, where their vegetation is characterised by species of the genera Isoetes, Marsilea and Pilularia313. On a calcareous substrate, other kinds of vegetation may be found in temporary pools, also including rare species of the genera Ranunculus, Damasonium and Elatine.

Vulnerability and threats Temporary pools are very vulnerable habitats due to their shallow depth of water and their frequently small surface area. Further, the species which colonise them are often inconspicuous and little known. Despite an improving public perception of wetlands over recent years, temporary pools are often poorly identified and their importance not appreciated, leaving them vulnerable to unintentional destruction. Within the Mediterranean Basin, the conservation of temporary pools has for thousands of years been compatible with, and even favoured by, agricultural activity. Today, economic conditions along both shores of the Mediterranean are undermining the conditions for their conservation. Modern agriculture enables these generally flat and only slightly flooded areas to be easily drained to create good agricultural land. They are also endangered by industrialisation and the development of tourism. A less common threat is their conversion to quasipermanent water bodies to form reservoirs, for use in flood regulation or protection against fire or even to be managed for hunting, fish farming or wildlife conservation.

Objectives and limitations of the management guide This book has the objective of aiding the conservation of Mediterranean temporary pools by taking into account their richness and their ecological functioning. It is aimed first and foremost at site managers throughout the Mediterranean region. It aims to provide them with the information necessary to identify these habitats, to improve their understanding of their functioning and the ecology of the species which inhabit them and, finally, to enable them to manage and restore degraded sites.

11

Mediterranean temporary pools

Roché J.

The book has been produced as part of the LIFE-Nature project, “Conservation of Mediterranean Temporary Pools No. 99/72049”. This project, which is dedicated to Mediterranean temporary pools in southern France, will eventually be named LIFE “Temporary Pools”. It draws widely on management experiments carried out over the course of this programme, but also on the literature and the expertise of scientists from a range of disciplines throughout the Mediterranean region. The analysis of their ecological functioning provides a basis for this discussion. The guide has therefore been conceived not as a series of directly applicable “recipes” but rather as a framework for activities tailored to each individual situation. It is supplemented, in the second volume, with a series of detailed notes on some important species of Mediterranean temporary pools.

A remarkable temporary pool, the Catchéou pool in the Bois de Palayson (Var, France)

12

The scope of this guide principally covers the European Union priority habitats and in particular oligotrophic* temporary pools. However, while the species may be different, the ecological processes are very similar to those of other types of temporary wetlands. Many points are therefore equally applicable to other temporary habitats (pools in brackish conditions, for example) and so examples have occasionally been borrowed from other types of temporary pools.

2. Biodiversity and conservation issues a. Habitats Yavercovski N., P. Grillas, G. Paradis & A. Thiéry

Introduction A “temporary wetland” is a habitat defined by alternating phases of flooding and drying out, irrespective of the duration or frequency of these phases. A wide range of wetlands fall within this definition: the fluctuating fringes of permanent water bodies (lakes, lagoons, ponds, etc.), temporary pools and streams, floodplains, and also artificially modified habitats such as ricefields or saltworks. Their distribution is principally determined by climatic characteristics (rainfall/evaporation regime), and to a lesser extent by the geomorphology of the site and of its catchment area. The majority are found in regions subject to a marked alternation of dry and wet seasons, i.e. in tropical, Mediterranean, arid and semi-arid climates16, 47 (see chapter 1). There are temporary pools in practically all the countries of the Mediterranean Basin and their islands (see Chapter 2b and Box 3). Most of the classifications relating to temporary wetlands are based on the predictability of flooding and its duration (Tab. 1).

Temporary pools are known by a wide range of names throughout the world: dayas in Morocco (not to be confused with dayet, a permanent lake), turloughs in Ireland (pools whose water level varies with the tide), polje (karstic subsidence basins) in Slovenia, potholes or vernal pools in North America, vleis in South Africa, padule in Corsica, etc. Each of these names reflects different hydrological, morphological, geographical and cultural features. Despite the wide range of environmental conditions to which they are subjected, certain groups of organisms (plants, ostracod and branchiopod crustaceans, amphibians, etc.) are characteristic of temporary pools all around the world. There are a number of different classifications for temporary pools. They are distinguished by the relative importance attached to different classification criteria: duration and frequency of flooding, origins, substrate, hydrological regime, physical and chemical properties of the water. The CORINE Biotope system34, for example, is a system for classifying habitats within the European Union, defined on the basis of phytosociological classification of plant communities (Box 4). In the Mediterranean, these habitats share two common characteristics: • flooding, almost always following rainfall, mostly in autumn and spring, • invariably a period of drying out, which is variable in length but always for several months. Within the general classification of wetlands (Tab. 1) Mediterranean temporary pools are associated with seasonal temporary wetlands, i.e. those having a predictable flooding regime.

Table 1. Simplified classification of temporary wetlands (modified from Boulton & Brock47)

Flooding regime

Predictability and duration of flooding

Ephemeral

Filled only after unpredictable rain and by run-off. The flooded area dries out during the days following the flooding and rarely supports macroscopic aquatic organisms. 10 years

Dry for 9 years out of 10, with rare and very irregular flooding (or wet periods) which may last for a few months.

Episodic 10 years

Alternating wet and dry periods, but at lower frequency than seasonal wetlands. Flooding may persist for months or years.

Intermittent 10 years

2 years

Alternating wet and dry periods every year, in accordance with the season. Usually fills during the wet season of the year, and dries out in a predictable way on an annual basis. The flooding lasts for several months, long enough for macroscopic animal and plant organisms to complete the aquatic stages of their life cycle.

2years

Predictable flooding, though water levels may vary. The annual input of water is greater than the losses (does not dry out) in 9 years out of 10. The majority of organisms living here will not tolerate desiccation.

Seasonal Jan.

Jan.

Near-permanent

13

Mediterranean temporary pools

The drought, which until recently was still considered to be a “terrible catastrophe” for the biological communities of these habitats, has, on the contrary, proved to be the most important factor in maintaining their biological uniqueness (richness, diversification of adaptive strategies, high productivity, resilience, etc.). In all these regions, the vegetation and fauna of the pools shows similarities, such as the presence of rare pteridophytes (Marsilea spp., Isoetes spp., Pilularia spp.) or the abundance of phyllopod, cladoceran, ostracod and copepod crustaceans.

Box 3. Temporary pools in Algeria and the Maghreb In Algeria, temporary pools are the commonest and most characteristic hydrosystems. Among the organisms most typical of these habitats, calanoid copepods (microcrustaceans traditionally categorised as zooplankton) occupy a prominent position340. Examples include species which are endemic* to North Africa or which have a restricted distribution around the Mediterranean Basin, such as Copidodiaptomus numidicus and Hemidiaptomus gurneyii. Some calanoids are rare, such as Diaptomus cyaneus, or associated with brackish or saline pools, such as Arctodiaptomus salinus and Arctodiaptomus wierzejskii. In the Maghreb, many species of water fleas (other microcrustacea) of the genus Daphnia swarm only in temporary pools. Among aquatic insects, many species have developed strategies for survival and breeding (migration, developmental diapause*, etc.) that are adapted to the fact that their habitat dries out for long periods. For example, the dragonflies Aeshna mixta, Sympetrum meridionale and Sympetrum striolatum migrate to high mountain woodlands to spend the summer months. In autumn they leave this refuge and come back down to breed337. The Zygoptera (damselflies) Lestes barbarus and Lestes viridis spend the summer around stands of alders, where the ambient microclimate protects them from desiccation. This extended sexual maturation (3-4 months) allows many species to avoid breeding at an unfavourable time338. Amphibians are also adapted to the vicissitudes of the Mediterranean climate (precocious breeding among species with slow development; delayed egg laying for those with rapid development). The Algerian Ribbed Newt, Pleurodeles poireti, a species endemic to Algeria and Tunisia, depends on temporary freshwater pools405, where amphibians generally encounter fewer predators, despite the frequent presence of the Little Egret, Egretta garzetta, which feeds preferentially in these habitats. Since the pioneering work of Gauthier159, few studies have been carried out into Algerian pools. However, recently, the Laboratoire de Recherche des Zones Humides (Annaba University) has carried out a series of studies of the biodiversity, structure and functioning of temporary pools. The preliminary results suggest that ecological factors such as soil texture and salinity determine the spatial structure, while temporal patterns are closely linked to the seasonal regulation of the various taxa. Samraoui B.

14

The diversity of Mediterranean temporary pools Various types of Mediterranean temporary pools may be distinguished, depending on their origin, the substrate on which they lie, their morphology and their formation. Very different substrate types confer specific physicochemical characteristics. The underlying substrate may be basic (limestones, etc.) or acid (granite, rhyolite, etc.) and may be compact rock or more or less permeable. They may be perched on rocky bars or situated in coastal plains. A proportion of these pools are of natural origin, resulting from various geomorphological processes. However, in some regions, pools of artificial origin, constructed for specific purposes (watering places for livestock for example), or resulting indirectly from human activities (mineral extraction, etc.), are common. Very ephemeral habitats, such as ruts, are not discussed here, even though organisms which are characteristic of temporary pools, particularly crustaceans, can live in them.

Box 4. Phytosociology, the basis for the classification of

habitats in the European Union Phytosociology is the study of plant communities and of the way in which plant species can be grouped within biotopes with precise ecological and site-specific characteristics. Formulated in particular by Braun-Blanquet53, 55 during his vegetation studies in the Mediterranean Languedoc, phytosociology allows a detailed typology of plant communities to be drawn up. The key element of phytosociology based on the plant list is the floristic association, of which several definitions have been proposed; initially in the strictest sense of the term: “a floristic association is a grouping of a defined floristic composition which appears in the same form wherever the same local conditions are found. It is by definition an ensemble of species whose coexistence depends directly on the environment”269, this definition gradually became broader: “a floristic association is a unique combination of species of which some, defined as characteristic, are specifically associated with the association, the others being defined as companion species”176. Barbero24 suggested that “the characteristic species are, within a given bioclimatic complex, the species most intimately linked to a habitat, and sometimes to a complex of habitats, where they attain their optimum development”. The floristic association, an abstract concept, is represented in the field by individuals belonging to the association (homogenous plant community observed in the field and belonging to the association in question), which may be characterised by complete plant lists drawn up for a given area, and considered by the phytosociologist to be homogenous with regard to the flora and the vegetation. To name an association, the phytosociologist selects one or two characteristic or dominant species. The suffix -etum is added to the root of the genus name of the main, determining species, and the species part of its name is put into the genitive case. The second qualifying species is also placed in the genitive, but its generic name ends in o, i or ae. Hence, the association characterised by Isoetes duriaei and Nasturtium aspera will be named Isoeto duriaei-Nasturtietum asperae. The associations are grouped according to floristic affinity into Alliances, which are themselves collected into Orders. Based on Quézel & Médail 315

2. Biodiversity and conservation issues

Pools of natural origin The natural processes leading to the creation of the pools are principally erosion and siltation. Erosion may result from the physicochemical action of water (dissolution of limestone for some cupular pools and poljes, with removal of sediments), from wind action (removal of fine sediments), from geomorphological processes associated with the realignment of watercourses, and also from these processes in combination, perhaps combined with the effects of the fauna or even the flora49, 263, 380. Natural siltation limiting drainage or run-off may contribute to the formation of pools (e.g. the series of endorheic* depressions northwest of Benslimane in Morocco, or the pools on the Permian substrates of the Plaine des Maures). The origins of temporary pools have important consequences for their richness and their functioning, particularly their hydrological regimes (see chapter 3b) and the potential connections between populations of animals or plants (see chapter 3f). A large number of types of natural pools may be distinguished according to their origins. A few characteristic types are described below.

Box 5. Mediterranean temporary pools in France An initial inventory, carried out in 2003 in the French Mediterranean region391, allowed 106 sites to be identified, representing more than 900 temporary pools, the majority relevant to Habitat 3170, “Mediterranean Temporary Pools”. Some Mediterranean temporary pools are found to the north of the Mediterranean region (especially Poitou-Charente). Three major types of pools may be distinguished on the basis of the substrate260: • brackish temporary pools of coastal wetlands: Camargue, Basse Crau, coastal fringes of Languedoc, Corsica, • temporary pools of fairly mineralised water, more often than not on calcareous substrates. These are the pools of the garrigues of Languedoc (the garrigues of Montpellier and Uzès, la Gardiole, the Causses méridionaux) and, in Provence, the Estagnolet pool at La Barben, the pool on the Cengle plateau, and the pools of the central Var, • temporary freshwater pools, on generally thin soils with a sandy or silty texture, poor in humus, with acid pH or weakly alkaline. In the Provence-Alpes-Côte d’Azur (PACA) Region, from east to west, are to be found: the Biot and Estérel massifs, the Colle du Rouet, the Plaine de Palayson, Plaine des Maures and Plaine de Crau. In Languedoc-Roussillon, from east to west, lie: the Etang de Capelle, the Costière Nîmoise, the Agde area, the basaltic plateau of Pézenas, the Plaine de Béziers, the plateaux of Roque-Haute and Vendres, the pools of Saint-Estève and the Plateau de Rodès. In Corsica, from north to south, lie the pools of Cap Corse, the Agriates, the coast of the southwest, Porto-Vecchio and Bonifacio. Although they amount to a very small total area (beyond doubt less than 1000 ha), Mediterranean temporary pools support, in France, several hundred plant species (see chapter 2b), 14 species of amphibians (Chapter 2c), 18 species of anostracan crustaceans (Chapter 2d) and many species of insects (Chapter 2e). Yavercovski N., M. Cheylan & A. Thiéry

Cupular pools These pools, which are small (a few tens of square centimetres or square metres) and which have very reduced catchment areas (Box 7), are created by erosion within blocks of bedrock or rock layers. Their water supply comes entirely from rainfall. Their sediments become extremely desiccated during the dry phase. These pools are characterised by a shallow soil and by an inconspicuous vegetation consisting of small and often rare species. They are found for example in Morocco on the limestone layers of the Chaouia380, in Malta on the limestone layers of Kamenitzas21, 223, on the island of Capri in Italy277, and in France on rhyolite in the Box 6. The dayas of Morocco Morocco is considered to be the foremost country in the Mediterranean Basin for its richness in temporary pools, locally known as dayas. They are widely distributed across the whole of the country, at low density in the east, the south and at high altitudes, and at high density in the western coastal zone between Tangiers and Tiznit. The degree of flooding decreases from north (six to eight months) to south (one to two months), and from west to east. From a biogeographical point of view, there is a very distinct predominance of Mediterranean and cosmopolitan species, while Atlantic taxa are poorly represented. In Morocco, the wide range of climatic, geological and geomorphological conditions is the basis of a remarkable diversity of dayas. Research carried out on crustaceans by Ramdani318 and Thiéry380 has enabled four principal groups of dayas to be distinguished: • Dayas of the arid eastern plateaux close to the Algerian border and of the Saharan zones south of the Atlas mountains: confined to plains at altitudes between 900 and 1400 m which receive less than 200 mm of irregularly distributed precipitation per year, the duration of flooding is from 15 to 75 days and they may remain dry for several years. They are shallow and, for the most part, of natural origin. • Dayas of the interior arid plains (Jbilets and the Haouz near Marrakech): situated on plains with an arid bioclimate at 300 to 1000 m altitude, receiving 200 to 400 mm of water per year, the flooding period is from 2 to 4 months. The substrate is schistose and produces a clayey soil by weathering. • Dayas of the coastal Atlantic plains (Gharb, Rabat with the Cork Oak forests of Mamora, the Benslimane region, from Casablanca to Settat and Essaouira): in the Atlantic low-altitude plains (<500 m) in a sub-humid and semi-arid climate, receiving 400 to 800 mm of water per year, these dayas have a flooded period of between 5 and 7 months. The soil is either hydromorphic over a sandstone or schist substrate (Benslimane dayas), or sandy over an impermeable clay layer (Mamora dayas). • Mountain dayas (Middle Atlas, High Atlas, Rif mountains): these are situated at high altitudes (>2000 m) in a humid bioclimate, and receive over 800 mm of water per year, directly from rainfall and indirectly from melting snow. The flooding period is from 3 to 6 months. The substrate here is of basalt, dolomitic limestone or Permian-Triassic red sandstone. Rhazi L.

15

Mediterranean temporary pools

Poljés and dolines These pools are created by karstic dissolution and/or subsidence. They form depressions characterised by more or less complex hydrological links with the subterranean karst, and support a very rich flora and fauna. (cf Box 13, Chapter 3b). They are found for example in France in Provence (central Var), Languedoc (the Lac des Rives on the Causse du Larzac, Valliguières pool in the Gard), in Corsica (in the Bonifacio limestone: Padulu and Musella pools), in Slovenia (whence their name), and in Morocco, in the Middle Atlas (limestone plateau of Ain Leuh, Azrou, etc.) and on the plains of the west, in the south of Benslimane Province. Pools associated with river dynamics (but not connected with the watercourse) Close to the main beds of watercourses, these slight depressions, less than one metre deep, may be filled by rainfall and/or fluctuations in the water table, depending on the situation. In France,

Box 7. The cupular pools of the Colle du Rouet At the Colle du Rouet (Var), cupules, hollowed out in rhyolitic tabular formations often form, on the same pavement, systems consisting of tens of pools. The presence of connections between the pools imply that they function as communicating basins. Through the action of periodic storms, sediments that accumulate at the bottom of cupules situated at high levels are carried away by the water and may on occasion be redistributed into neighbouring cupules. This type of functioning would explain: • the maintenance of vegetation of a pioneer* type in the majority of cupules; • the spread of species from one cupule to another; • the occurrence of very variable water levels and vegetational stages in different cupules. For the plants and crustaceans of the temporary pools, the effect of storms will therefore be positive to the extent that it counteracts the threat posed by infilling, but negative when the whole of the seedbank and all eggs are washed away. In a study of the cupular pools of the island of Gavdos (Greece), small pools (<1 m2 and <50 cm deep) hollowed out in calcareous or ophiolitic rocks, Bergmeier30 found a clear relationship between the depth of the pools, which influences their drying-out date, and their vegetation. He defined five types of pools on this basis: from the more aquatic pools flooded up to May, with Zanichellia and Callitriche pulchra as characteristic species, to more terrestrial pools, holding water only up to the beginning of March, with Tillea alata and Crepis pusilla. At the Colle du Rouet, the vegetation of 14 cupules situated on the same rhyolitic surface (Fig. 1) was studied using the quadrat transect method. In each cupule, the plant species richness (range: 1 to 22) was strongly correlated with the mean depth of the sediment (range: 1 to 8 cm). A classification of pools carried out on the basis of pool depth and mean sediment depth reveals four quite different groups: • shallow cupules (mean 5 cm) with skeletal soils, very speciespoor with Crassula vaillantii,

16

the pools of the Ile de la Barthelasse at Avignon, and the pools of Cerisières at the Tour du Valat in the Camargue belong to this type of formation. Pools in slight depressions in the land surface These pools occur on impermeable clayey-silty substrates, most often isolated from the water table and often shallow. In Corsica (France), the Tre Padule are examples of this type of pool. Pools of dune systems These pools occupy the slacks between the dunes in active or fossil dune systems. They are well developed on the Moroccan coast (Benslimane Province) where consolidated dunes are aligned at right angles to the general slope of the plateaux and form obstacles to the flow of watercourses111, 323. They may also be seen on the Languedoc coast and in Spain.

Pools of artificial origin People have created ponds and pools for use in livestock farming, transport networks, irrigation and water storage. Over time these

• deep cupules (mean 10 cm) with thin soils, species-poor with Callitriche brutia, Isoetes velata, Crassula vaillantii and a few amphibious species, • deep cupules with deep soils (>5 cm on average) wet enough to support perennials such as Isoetes velata, Mentha pulegium and several small annual rush species (Juncus bufonius, etc.), • shallow cupules with deep soils (2.4 cm on average) with many species and richer in terrestrial species than the other groups. These cupular pools are populated by invertebrates with short life cycles166: a few anostracan branchiopods such as Tanymastix stagnalis, cladocerans, ostracods and cyclopoid copepods. As well as these crustaceans there are a few insects, most commonly Diptera (larvae of Culicidae, Ceratopogonidae and Chironomidae). In all cases these are migrant insects of unspecialised habitats, described as opportunists. Pichaud, M., E. Duborper & N. Yavercovski

Catard A.

Var (Esterel), on limestone in the Bouches du Rhône (Lamanon), and on granite outcrops in Corsica.

A system of cupular pools (Colle du Rouet, Var, France)

2. Biodiversity and conservation issues

habitats have been colonised by biological communities whose composition and structure change fairly frequently according to the age of the habitat. Among the wide range of different types, the following may be mentioned:

Rock extraction sites Temporary pools today fill the holes formed in former quarries by the excavation of various rocky materials. In France, the ponds among the limestone peaks north of the Etang de Berre, and the Roque-Haute Nature Reserve with its 205 pools deriving mostly from basalt extraction97, provide examples.

Roché J.

“Lavognes” on the Causses (Southern France) These watering places for sheep consist of small circular depressions with a natural bottom, lined with stone or concrete. The period for which they hold water is very variable from site to site. They can constitute very important habitats in these regions, which are lacking in natural watering places.

A pool created by basalt excavation at Notre-Dame de l’Agenouillade (Hérault, France)

Figure 1. An ensemble of cupular pools on rhyolitic rock layer (Colle du Rouet, Var, France): topographical map

Relative elevation (m)

Map: M. Pichaud & E. Duborper - Station biologique de la Tour du Valat

1.8 + 1.8 - 1.7 1.7 - 1.6 1.6 - 1.5 1.5 - 1.4 1.4 - 1.3 1.3 - 1.2 1.2 - 1.1 1.1 - 1 1 - 0.9 0.9 - 0.8 0.8 - 0.7 0.7 - 0.6 0.6 - 0.5 0.5 - 0.4 0.4 - 0.3 0.3 - 0.2 0.2 - 0.1 0.1 - 0 Boundaries of catchment areas Boundaries of deposits

0

1

2m

Overflows

17

Mediterranean temporary pools

Water reservoirs Some pools develop from small reservoirs, used for irrigation (the Catchéou pool in the Var, pools close to villages in Morocco, etc.) or for fire-fighting (Plaine des Maures). In Corsica, in the eastern plain, huge reservoirs, almost completely dry from May to September, have been built in the valleys and depressions for use in arboriculture as well as sheep and cattle raising. The reservoir at Teppe Rosse, near Aléria, is the most interesting from the point of view of plant biodiversity. Its gradually sloping banks promote the establishment of summer species rare in Corsica (Gratiola officinalis, Pulicaria vulgaris, etc.), depending upon how much water is drawn off for irrigation289, 290. Storm-water tanks and pollution-control tanks built alongside motorways These artificial habitats, whose purpose is to protect against flooding and pollution, have proved to be veritable hotspots of biodiversity, for plants as well as animals (invertebrates and amphibians343, 344, 345). Their substrates may be natural or formed from liners with a thin layer of sediment. These sites are good models for use in analysing the effects of pollutants (metals, hydrocarbons, etc.) on living organisms202.

The legislative and institutional framework The European Directive of 21 May 1992 on the conservation of natural habitats and wild fauna and flora118 is more commonly known as the Habitats Directive. It classifies as being “of European Community Interest” the habitats listed in its Annexe I, among which are distinguished some particularly noteworthy habitats, categorised as “priority habitats”. It also lists, in Annexe II, a number of animal and plant species whose habitat should be subject to conservation measures. The member countries of the EU are committed to the protection of the habitats of Annexe I of the Habitats Directive and the habitats of the species in Annexe II, through the designation of “Special Areas of Conservation” which make up the “Natura 2000 Network”. Among the wide range of temporary pool habitats, some are considered by the EU to be particularly important because of heightened conservation issues associated with the rarity and uniqueness of their animal and plant communities and with their specialised ecology. They are grouped within two habitats of Annexe I of the Habitats Directive, with the following codification and description: • Oligotrophic,* weakly mineralised waters on usually sandy soils in the western Mediterranean (Natura 2000 code: 3120), • Mediterranean temporary pools (Natura 2000 code: 3170), a habitat given priority designation. The Manual of Habitat Interpretation published by the EU15 gives more precise definitions and allocates these habitats to basic habitat types, listed together with their characteristic species. In France, the basic habitats are the subject of detailed notes in the Habitats Register158, where they are described at their most most detailed level, i.e. that of the plant association. It is important to distinguish the pool, which is an ecological, functional and landscape unit, from the “Mediterranean Temporary Pools” habitats recognised to be of EC-wide interest in the Habitats Directive. In a single pool both the habitat of EC interest and the priority habitat (3120 and 3170 respectively) may coexist, as is often the case at the Plaine des Maures in the

18

Box 8. How are the habitats designated as of EC-wide

interest or priority to be identified in a temporary pool? This simplified key to habitat identification is not a key to the identification of phytosociological units. However, it should enable the site manager to determine whether or not a pool contains a habitat of EC interest or priority. It applies only to habitats in mainland France and Corsica (Fig. 2). The identification of Habitats 3120 and 3170 is based on whether the substrate has an acidic or basic character, the length of the flooding period and the composition of the amphibious plant communities: the non-exhaustive lists of “key species”, used to characterise the habitats, include species belonging to various regions and to different vegetation units. 1.

- Siliceous (acid) substrate, flooding during winter and all or part of spring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 – Substrate neutral or basic lime-rich, delayed drying out (summer or autumn) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.

– Flooding limited (saturation), irregular, mostly winter, Serapias grasslands in the crystalline areas of Provence: Habitat 3120: oligotrophic*, very weakly mineralised water over usually sandy soils of the West Mediterranean (phyto-

sociological alliance: Serapion, Aubert & Loisel, 1971). Key species: Serapias spp., Oenanthe lachenalii, Chysopogon gryllus, Isoetes histrix. – Flooding more regular and for longer periods, spring or summer amphibious species. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3.

– Shallower than 0.4 m, amphibious species growing in early spring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 – Deeper than 0.4 m, species growing in late spring or summer: Habitat 3170: Amphibious Mediterranean grasslands flooded for long periods (phytosociological alliance: Preslion

cervinae Br.-Bl. Ex Moor 1937). Key species: Mentha cervina, Artemisia molinieri, Trifolium ornithopodioides, Oenanthe globulosa.

4.

- Groupings dominated by species of the genus Isoetes: Habitat 3170: Mediterranean temporary pools with Isoetes

(phytosociological alliance: Isoetion Br. Bl. 1936). Key species: Isoetes spp., Marsilea strigosa, Pilularia minuta, Litorella uniflora, Ranunculus revelieri, Crassula vaillanti. - Grassland dominated by Agrostis pourretii. A little later than the Isoetion vegetation, they follow after them over the course of the season in Corsica291: Habitat 3170: phytosociological alliance Agrostion salmanticae Rivas Goday 1958 (= Agrostion pourretii Rivas Goday

1958). Key species: Agrostis pourretii, associated with Lythrum borysthenicum or Illecebrum verticillatum.

2. Biodiversity and conservation issues

Var. In addition, Habitat 3170 includes a large number of plant communities of which several may sometimes be seen together or may succeed one another over time in a single pool, in accordance with environmental gradients. Similarly, a pool may include a habitat recognised as being of EC-wide interest by the EU in just a part, small or large, of its area. Finally, in accordance with the interannual variability of the Mediterranean climate, the plant communities have an equally variable spatial distribution within the pool, from one year to another. It may even happen that some plant communities of the priority habitat do not appear in certain years. These factors often cause difficulties for the non-specialist in identifying habitats in the context of the Habitat Directives (Box 8). In each case, management needs to be undertaken on an appropriate scale, which is at the very least that of the pool, but which must often also include its catchment area.

5.

- Amphibious species growing in summer and autumn in nutrient*-rich, sometimes brackish substrates: Habitat 3170: Mediterranean halonitrophilous amphibious grassland (phytosociological alliance: Heleochloion Br.-Bl in

Br.-Bl., Roussine & Nègre 1952). Key species: Heliotropium supinum, Crypsis aculeata, Crypsis schoenoides, Cressa cretica. - Amphibious species growing in spring and summer, colonising richer, calcareous or basic substrates: Habitat 3170: Mediterranean annual amphibious grassland

(phytosociological order: Nanocyperetalia Klika, 1935) Key species: Damasonium polyspermum, Lythrum tribracteatum, Cyperus flavescens, Cyperus fuscus, Elatine macropoda, Teucrium aristatum. Yavercovski N. & G. Paradis based on Gaudillat & Haury158

Figure 2. Localisation of habitats of EU interest in Mediterranean continental France and Corsica

Avignon Nîmes Montpellier

?

Nice

Arles Aix en Provence

Cannes

0

50 km

Béziers Marseille

Narbonne

Toulon Bastia

Perpignan

Mediterranean Sea Ajaccio Habitats of European community interest Site Diffuse distribution Serapion ■ Priority habitats Isoetion Preslion Agrostion Heleochloion Nanocyperetalia

■ ■ ■ ■ ■

?

Porto Vecchio

Bonifacio Higt density Disappeared

Map: M. Pichaud & Nicole Yavercorvski - Station biologique de la Tour du Valat

19

Mediterranean temporary pools

b. Plant species Médail F.

From the point of view of the flora and the vegetation, oligotrophic freshwater* temporary pools are classified among the most biologically and biogeographically interesting ecosystems in the Mediterranean region. The relevant floristic assemblages are mainly distributed in the western Mediterranean: Spain330, Balearics238, Portugal201, Morocco49, 263, 323, 326, Algeria76, 77, Tunisia306, southern France260, Corsica242, 260, 291, Sardinia274 and Sicily67, 248. Structurally similar vegetational associations have also been reported from Libya66, mainland Greece and some of the islands of the Aegean Sea30, 31, 126, and more sporadically from Turkey214 where, however, there are some interesting but little-known areas (cf. the remarkable recent rediscovery of Pilularia minuta in the Izmir region178), as is also true of Syria (P. Quézel, pers. com.). While these habitats and plants are well known in some areas, it is for many reasons difficult to obtain a precise idea of the conservation issues at the Mediterranean level. Unspectacular and ephemeral, these habitats have often been under-recorded (especially in the eastern Mediterranean, where information has only recently begun to be obtained); the periods when the plants are absent during unfavourable years may give the impression that they have disappeared, whereas in fact they are still present in the form of the soil seedbank. These habitats bear the full brunt of human depredations (urban development, drainage, conversion to agriculture, eutrophication) and some very valuable areas are becoming rapidly degraded (notably in North Africa). Finally, the functioning of these complex systems remains poorly known, and conservation or restoration activities must rely on a limited body of knowledge. It is not easy therefore to produce a thorough summary for the whole peri-Mediterranean zone. However, thanks in part to surveys carried out within the LIFE “Temporary Pools” project, satisfactory information regarding temporary pools in southern France will be available from now on.

Species richness and plant diversity in Mediterranean temporary pools Mediterranean temporary pools support plant communities that are very rich in rare and threatened species. This high biodiversity is explained by the functional characteristics and dynamics of these systems. The unstable conditions and low productivity allow the coexistence of plants that are usually annual, weakly competitive and small in size. However, there is a high degree of spatio-temporal heterogeneity in this diversity and in the floristic composition which is closely dependent on variations in the dates of flooding37 (Chapter 3c). The usually positive relationship between number of species and surface area constitutes one of the oldest laws in ecology and biogeography*. This relationship has been confirmed for a suite of mid-European pools283, but not for the north Moroccan dayas323. In addition, temporary pools are generally larger in North Africa than in Europe76: an Isoetes velata pool a kilometre long and a hundred metres wide has, for example, recently been recorded in Tunisia. It is also usually agreed that in similar ecological conditions the temporary pools of North Africa have a greater floristic

20

Grillas P.

Introduction

Damasonium polyspermum and Elatine brochonii, two rare species in a daya in the dry phase (Benslimane, Morocco)

Box 9. Floristic diversity and human activities: the

example of the temporary pools of northwest Morocco A detailed study of the factors determining the development of floristic diversity was carried out at 30 pools (dayas) in Benslimane Province (Morocco). These pools are heavily influenced by people through continual agricultural activities, very heavy grazing pressure, and their use for washing by the local communities. These uses result in pollution by phosphates and by nitrogen-based fertilizer, and eventually in eutrophication of the water. However, the total floristic diversity of pools is not significantly different either between pools whose catchment area is used for agriculture or forestry or between different types of use (grazing only or crop growing plus grazing). Among the environmental parameters considered, only pH plays a significant role. The area of the pools has no effect. However, basing the analysis purely on the total number of species gives a poor indication of the effects of human uses, since a very specialised suite of rare plants, typical of the pools, is replaced by common plants that are more adapted to human disturbance (ruderal or generalist* species). Considering only the characteristic pool species, pools in woodland have more species than those in cultivated areas. Pools which are only grazed show a distinctly higher diversity of characteristic plants than those in areas which have been cultivated and then grazed (26 v. 20 species). This diversity increases with increasing maximum depth of water, the diameter of the water body in spring and the duration of flooding, but pH does not play a significant role. The ecosystems present in the area surrounding the pools also contribute to their floristic richness: the flora of Cork-Oak woodlands accounts for about 14% of the total species richness of woodland pools, and weeds of cultivation for about 20% of the total species richness of pool surrounded by agriculture. In spite of the major human activities, these dayas therefore conserve a significant series of characteristic species, since the long period of flooding in the centre of the pools generally constrains the degree of access by livestock and the potential for conversion to agriculture. However, rare plants are less common in disturbed pools. Médail F. and L. Rhazi based on Rhazi323; Rhazi et al.,326; Rhazi et al.327

2. Biodiversity and conservation issues

diversity than those in Europe. A group of small pools will also contain more species and will be more valuable from the naturalheritage point of view than a single pool of equivalent surface area283. Even so, a conservation strategy should not of course neglect larger pools, since the risk of local population extinctions decreases with increasing size of their habitats.

Plants dependent on Mediterranean pools: biogeographical aspects The unique character of the flora of Mediterranean temporary pools derives in the first place from a diverse assemblage of pteridophytes (Isoetes, Marsilea, Pilularia), often closely confined to these habitats. Their water requirements are variable. Next to these are plants that are strictly dependent on flooding, such as species of Callitriche or the various aquatic Ranunculus. Among other well-represented genera, Lythrum, Eryngium and Solenopsis may be mentioned. The distribution of the species of temporary pools is often fragmented, with populations separated by several hundred kilometres. Should they be seen as the vestiges of a formerly far wider and more continuous distribution, or as resulting from random dispersal over long distances by the wind (pteridophyte spores) or by birds? (Box 26 Chapter 3f). In the absence of any detailed studies, it is at present impossible to answer this biogeographical question. At all events, the main centre of radiation for the plant species under consideration lies in the western part of the Mediterranean Basin: Quézel313 estimated that fewer than a quarter of the species present in the west occur also in the eastern Mediterranean. In contrast with those in California205, the temporary pools of the Mediterranean Basin are characterised by a rather low degree of plant endemism (17 endemic* taxa , i.e. 17.5% of the total list of species characteristic of the pools: see Tab. 2). There are only a few endemic species, for example Eryngium atlanticum in Morocco, Isoetes heldreichii in Greece, Ranunculus revelieri (Corsica and Provence), Marsilea batardae and Ranunculus longipes (Iberian Peninsula), Solenopsis bicolor (Algeria and Tunisia) and Artemisia molinieri (Provence). The process of speciation has been incomplete in a number of cases where various endemic subspecies (8 taxa) have been described (e.g. Isoetes velata, Polygonum romanum, Ranunculus isthmicus, R. revelieri, Solenopsis minuta). The processes whereby these pools have been colonised have clearly been complex, and a number of different lineages may be distinguished: a typically Mediterranean lineage, most frequent, (Damasonium, Elatine, Kickxia, Lotus, Lythrum, Trifolium, etc.), a midEuropean lineage including Mediterranean-Atlantic taxa (Isoetes, Cicendia, Exaculum, Illecebrum, Littorella, Juncus, etc.), and a tropical plant lineage (Alternanthera, Marsilea, Oldenlandia, Laurenbergia).

Conservation issues and levels of protection around the Mediterranean Despite our limited knowledge of the distribution of the characteristic plants of Mediterranean temporary pools, a preliminary synthesis (Tab. 2) has attempted to draw up a list of the rare species (country by country). This list is based on information in various inventories, floras and Red Lists, drawn up at the national level and supplemented by some unpublished data.

This assessment currently includes 108 taxa of specific or subspecific rank. Spain, France and Italy each have a little over 60% of the total number of species listed; next come Morocco and Algeria with about 50% of the species. These countries are therefore of the highest priority as regards conservation issues, bearing in mind that it is in the Maghreb that the most critical anthropogenic threats occur. In the eastern Mediterranean Basin we note the fairly large number of plants recorded for Greece (42 taxa, i.e. 39% of the total), the result of surveys carried out

Box 10. Important conservation issues affecting bryophytes* Mediterranean temporary pools and marshes are important biotopes for bryophytes, especially Hepaticae (liverworts). However, only Riella (Riella helicophylla [see species notes], R. affinis, R. cossoniana, R. parisii, R. notarisii, R. numidica, R. bialata, etc.) are strictly dependent on these habitats. These taxa depend fundamentally on the flooding/drying regime to complete their development cycle. Around the pools Sphaerocarpos texanus is also found, a fairly close taxonomic relative of Riella but with different ecology. Although liverworts of the genus Riccia are not strictly confined to the areas around temporary pools, this is nevertheless a favoured habitat for them. About twenty species of Riccia (see species notes), may be observed in these situations (Riccia macrocarpa, R. michelii, R. beyrichiana, R. canaliculata, R. perennis, R. crystallina, etc.). The coexistence of many species in this genus at one locality is an important factor when one is attempting to assess the natural heritage value of a site. Other Marchantiales such as Oxymitra incrassata and Corsinia coriandrina are the typical inhabitants of the bottoms and surroundings of temporary depressions that are in the process of drying out. Fossombronia species (F. angulosa, F. crozalsii, F. pusilla, F. husnotii, etc.) are equally well represented. The leafy liverworts, such as Gongylanthus ericetorum, are, generally speaking, less well represented in these habitats. The anthocerotes are fairly frequent (Anthoceros agrestis, Phaeoceros bulbiculosus, P. laevis, etc.). There are also many tiny mosses in temporary pools. The Pottiaceae, a major family in the Mediterranean region, are especially well represented by the genera Phascum, Pottia, Acaulon, Weissia, Tortula, etc. The Funariaceae (Funaria microstoma or the genus Entosthodon, including E. obtusus, E. mouretii), species of the genus Bryum (Bryum alpinum, B. barnesii, B. bicolor, B. gemmiparum, B. klinggraeffii, B. pallens, B. tenuisetum), many members of which have effective methods of vegetative reproduction*, are generally abundant. The Ephemeraceae, minute and very delicate species, may also colonise the areas around temporary pools. Archidium alternifolium (Archidiaceae) may form large colonies in some temporary pools. There are many bryophyte species in these habitats which are rare at the national scale or around the whole of the Mediterranean, but through lack of knowledge they are not generally cited in lists of species of conservation concern or of protected species. Riella helicophylla is an exception to the rule in that it is subject to various designations (see species notes), including citation in Annexe II of the Habitats Directive. Hugonnot V. & J.P. Hébrard

21

Mediterranean temporary pools

Table 2. List of the rare and generally characteristic vascular plants (flowering plants and pteridophytes) of Mediterranean temporary

V

Egypt

Lybia

Tunisia

16

34

23

17

18

20

18

31

Algeria

Israel

42

Morocco

Lebanon

11

58

58

VU EN

RR RR

E

E

CR

AC I AC

I

RR R EN VU EN R

RR

RR RR

RR

AR

VU

Brassicaceae

R?

RR CR R

DD VU

EN CR

V

CR CR

R

RRR E

R

AC RR RR RR

E ? EX?

RR

RR V

RR

R RR E? AC RR R

RR R R

?

V

V

EX?

AC

V

Berne C.

RR

V V

RR AC R RRR AC RRR

VU ? ?

? VU RR AR EN RRR

HD II et IV

I

CR CR

HD II et IV

RR R

RR

V

Berne C., HD II et IV

V V V

EW

V V V

VU VU DD

?

R

RR RR RR R? K R? AC

RR RR RR AC R AC

R AC RR

R AC

E?

RR

R RR AC

RR

R RR

AC RR

V

V ?

Haloragaceae Asteraceae Apiaceae Rubiaceae Ophioglossaceae Ophioglossaceae Ophioglossaceae Marsileaceae Marsileaceae Polygonaceae Asteraceae Asteraceae Ranunculaceae Ranunculaceae Ranunculaceae Ranunculaceae Ranunculaceae Ranunculaceae Ranunculaceae Ranunculaceae Ranunculaceae Ranunculaceae Campanulaceae Campanulaceae Campanulaceae Campanulaceae Campanulaceae Campanulaceae Campanulaceae Lamiaceae Lamiaceae Fabaceae Fabaceae Verbenaceae Campanulaceae

Syria

8

Turkey

9

Cyprus

68

Albania

66

Greece

Croatia

49

R RR E?

Poaceae Poaceae Amaranthaceae Poaceae Apiaceae Apiaceae Asteraceae Alismataceae Fabaceae Callitrichaceae Callitrichaceae Callitrichaceae Callitrichaceae Callitrichaceae Callitrichaceae Callitrichaceae Callitrichaceae Callitrichaceae Gentianaceae Gentianaceae Brassicaceae Crassulaceae Cyperaceae Alismataceae Alismataceae Elatinaceae Elatinaceae Elatinaceae Elatinaceae Apiaceae Apiaceae Apiaceae Apiaceae Gentianaceae Molluginaceae Boraginaceae Illecebraceae Isoetaceae Isoetaceae Isoetaceae Isoetaceae Isoetaceae Isoetaceae Isoetaceae Isoetaceae Isoetaceae Cyperaceae Scrophulariaceae Scrophulariaceae Haloragaceae Campanulaceae Scrophulariaceae Plantaginaceae Fabaceae Fabaceae Lythraceae Lythraceae Lythraceae Lythraceae Lythraceae Marsileaceae Marsileaceae Marsileaceae Marsileaceae Marsileaceae Lamiaceae Poaceae Brassicaceae Boraginaceae Ranunculaceae Ranunculaceae

66

Malta

UICN 1997

Italy

Char. Intern. protec.

Portugal

Families

France

Rare vascular plants of Mediterranean temporary pools

Agrostis pourretii Willd. Airopsis tenella Alternanthera sessilis (L.) R. Br. Antinoria insularis Parl. Apium crassipes (Koch) Reichenb. fil. Apium inundatum (L.) Reichenb. Fil. • Artemisia molinieri Quézel, Barbero et Loisel Baldellia ranunculoides (L.) Parl. • Benedictella benoistii Maire Callitriche brutia Petagna Callitriche lenisulca Clav. Callitriche lusitanica Schotsm. Callitriche naftolskyi Warb. & Eig Callitriche palustris L. Callitriche platycarpa Kütz Callitriche pulchra Schotsman Callitriche truncata Guss. subsp. occidentalis Callitriche truncata Guss. subsp. truncata Cardamine parviflora L. • Centaurium bianoris (Sennen) Sennen Cicendia filiformis (L.) Delarbre • Coronopus navasii Pau Crassula vaillantii (Willd.) Roth. Cyperus hamulosus M. Bich Damasonium bourgaei Coss. Damasonium polyspermum Coss. Elatine alsinastrum L. Elatine brochonii Clavaud • Elatine gussonei (Sommier) Brullo et al. Elatine macropoda Guss. • Eryngium atlanticum Batt. & Pitard Eryngium corniculatum Lam. • Eryngium galioides Lam. Eryngium pusillum L. Exaculum pusillum (Lam.) Caruel Glinus lotoides L. Heliotropium supinum L. Illecebrum verticillatum L. Isoetes duriei Bory • Isoetes heldreichii Wettst. Isoetes histrix Bory • Isoetes olympica A. Br. Isoetes setacea Lam. • Isoetes velata A. Braun subsp. intermedia (Trabut) Maire & Weiller • Isoetes velata A. Braun subsp. perralderiana Isoetes velata A. Braun subsp. tegulensis Batt. & Trabut Isoetes velata A. Braun subsp. velata Isolepis setacea (L.) R. Br. Kickxia cirrhosa (L.) Fritsch Kickxia commutata (Reichenb.) Fritsch subsp. commutata Laurenbergia tetrandra (Schoot.) Kanitz in Martius • Legousia juliani (Batt.) Briq. Limosella aquatica L. Littorella uniflora (L.) Ascherson Lotus angustissimus L. Lotus conimbricensis Brot. • Lythrum baeticum Silvester Lythrum borysthenicum (Schrank) Litv. Lythrum thesioides M. Bieb. Lythrum thymifolium L. Lythrum tribracteatum Salzm. ex Sprengel Marsilea aegyptiaca Willd. • Marsilea batardae Launert. Marsilea minuta L. Marsilea quadrifoliaL. Marsilea strigosa Willd. Mentha cervina L. Molineriella minuta (L.) Rouy • Morisia monanthos (Viv.) Ascherson Myosotis sicula Guss. Myosurus minimus L. Myosurus sessilis S. Watson Myriophyllum alterniflorum DC. • Nananthea perpusilla (Loisel.) DC. • Oenanthe lisae Moris Oldenlandia capensis L. fil. Ophioglossum azoricum C. Presl. Ophioglossum lusitanicum L. Ophioglossum polyphyllum A. Braun Pilularia globulifera L. Pilularia minuta Durieu ex A. Braun • Polygonum romanum Jacq. subsp. gallicum (Raf.) Raf. & Vill. Pulicaria sicula (L.) Moris Pulicaria vulgaris Gaertn. Ranunculus batrachioides Pomel Ranunculus isthmicus Boiss. subsp. isthmicus • Ranunculus isthmicus Boiss. subsp. tenuifolius Ranunculus lateriflorus DC. • Ranunculus longipes Lange ex Cutanda Ranunculus ophioglossifolius Vill. • Ranunculus revelieri Boreau subsp. revelieri • Ranunculus revelieri Boreau subsp. rodiei (Litard.) Tutin Ranunculus saniculifolius Viv. Ranunculus trilobus Desf. • Solenopsis balearica (E. Wimm.) Aldasoro et al. • Solenopsis bicolor (Batt.) Greuter & Burdet Solenopsis laurentia (L.) C. Presl. • Solenopsis minuta (L.) C. Presl subsp. annua Greuter, Matthäs & Risse • Solenopsis minuta (L.) C. Presl subsp. corsica Meikle Solenopsis minuta (L.) C. Presl subsp. minuta • Solenopsis minuta (L.) C. Presl subsp. nobilis (Wimm.) Meikle Teucrium aristatum Pèrez Lara Teucrium campanulatum L. Trifolium cernuum Brot. Trifolium ornithopodioides Oeder Verbena supina L. Wahlenbergia lobelioides (L. fil.) Link subsp. nutabunda (Guss) Murb.

Spain

pools (Médail, unpublished)

V

V

EN VU

Berne C.

V

VU LR

R

RR

RR

E?

R

RR RRR

R

LR

CR VU

RR

? VU

RR

RR

CC

RR RR

? VU LR

RR RR R

R

V

VU

?

RR

EX? V V ?

V V

R

R

AC

E RR EX?

VU R AR R

R

E R

R

E EN

? VU

E

RR

R R?

AR RR

AC

• Mediterranean endemics* vulnerable-threatened species according to their global distribution area, their population number and present threats Indications of the categories of threats sensu IUCN395 or rarity according to National Red Data Books and Red Lists or plant guides. International protection: Berne C.: Berne Convention or “Convention relating to the conservation of the wildlife and the natural environment in Europe” of 19 September 1979; HD: Habitats Directive of 21 May 1992118. General source of data: Med-Checklist170 and Flora Europaea392 for the European area of the Mediterranean region, supplemented by the following plant guides and publications: Spain and the Balearics: Castroviejo71 and indications of IUCN criteria based on Dominguez Lozano119 ; France: Médail et al.260 and indications of IUCN criteria based on Olivier et al.285 ; Italy: Pignatti299 and indications of IUCN criteria based on Conti et al.87 ; Malta: indications of IUCN criteria based on Lanfranco222 ; Greece: Economidou126 and Bergmeier & Raus31, indications of IUCN criteria based on Phitos et al.297 ; Cyprus: Meikle262 ; Turkey: Davis102, Davis et al.103 ; Syria-Lebanon: Mouterde276 ; Israel: rarity criteria based on Shmida et al.358 ; Egypt: Boulos45, 46 ; Libya: Brullo & Furnari66 ; Tunisia: Pottier-Alapetite307 ; Algeria: rarity criteria based on Quézel & Santa316 ; Morocco: rarity criteria based on Fennane & Ibn Tattou138 and Rhazi (unpublished.). The chorology of Damasonium is based on the work of Rich & Nicholls-Vuille329.

22

2. Biodiversity and conservation issues

Box 11. The role of charophytes* in temporary pools Charophytes are green plants which resemble macrophytes and which are attached to the substrate by rhizoids*. These pioneer* plants quickly form a dense submerged vegetation known as “charophyte meadows”. They are of considerable importance in the functioning of temporary pool ecosystems, where their dry biomass may reach 400 to 500 g/m2 (130). These carpets of plants provide shelter and egg-laying sites for invertebrates and fish. It is common to see “swarms” of ostracod eggs laid in the shelter of the whorls of the charophytes.

Roché J.

The Characeae are eaten by many invertebrates (crustaceans, amphipods and molluscs). In lakes they also provide food for fish, crayfish and some birds, for example Red-crested Pochard (Netta rufina)398 and may form up to 90% of the diet of Anatidae177. Charophytes also provide an indirect dietary resource; the thalli provide a surface covered with thousands of epiphytes which are grazed by invertebrates.

Artemisia molinieri, a species endemic to a few pools of the Centre-Var (France)

mainly over the last decade, and to a lesser degree for Turkey (34 taxa). The countries of the Near East and especially the Balkans support a fairly limited share of species, perhaps due to underrecording. Nevertheless, some are of the very highest degree of conservation importance (e.g. Callitriche naftolskyi in Israel and Syria). The importance of some of the large Mediterranean islands, notably Corsica and Sardinia, should also be stressed. On the other hand, pools have suffered from significant impacts or have locally disappeared on other islands such as Malta and Sicily, where the richest areas now appear to be confined to various satellite islands (Pantelleria, Lampedusa, Favignana, etc.) that have been less affected by humans. Based on their overall range and on information about the rarity of the various species in different countries, it is possible to produce a preliminary list of 38 of the rarest and most threatened plants of temporary pools around the Mediterranean perimeter (Tab. 2). Among these taxa, Benedictella benoistii, endemic to northwest Morocco, has not been seen for several decades. Several pteridophytes characteristic of the pools (Pilularia minuta, P. globulifera, Marsilea minuta, M. strigosa, Isoetes setacea) are also seriously threatened at the majority of their sites. In North Africa, the status of a number of taxa of tropical origin (Alternanthera sessilis, Laurenbergia tetrandra, Marsilea minuta, M. aegyptiaca and Oldenlandia capensis), which are highly localised in the form of biogeographical isolates, is currently completely unknown. Furthermore Callitriche and Elatine appear to be threatened across their range. Priority for conservation should in the first instance be given to very localised endemic plants such as Artemisia molinieri, Lythrum baeticum, Legousia juliani, Solenopsis balearica and/or Coronopus navasii. At the international level, the plants of temporary pools are still subject to very limited and clearly inadequate protection measures. Only four taxa are listed in the Habitats Directive118: Marsilea

The Characeae as a whole are found over a wide range of physicochemical conditions, from slightly acid to strongly alkaline water, with a pH range from 6 to 9.5. Their temperature tolerance ranges from the boreal zone to the equator, depending on species. Species of the genus Chara play a part in the carbonate cycle through the massive incrustations of their thalli with microcrystalline calcite and through the calcification of their gyrogonites*130, 390. They also contribute significantly to the oxygenation of the water401. Characeae are able to survive in temporary habitats thanks to their oospores* which, uniquely in the plant world, are spiralshaped. In many species the oospores become calcified during the lifetime of the plant and are then known as gyrogonites. The gyrogonites allow species to be identified in the “seedbank”, including rare species360. Charophytes are known from as long ago as the Upper Silurian (420 mya) thanks to fossil gyrogonites. Dispersal is carried out mainly by birds, which carry the gyrogonites not only in their plumage but also in their digestive track. Passage through a duck’s gut in no way affects the viability of the gyrogonites309. This is why bird migration routes from Scandinavia to southern Europe are “signposted” with a chain of lakes in which the boreal species Nitellopsis obtusa is found. During the Holocene wet phases when there were suitable lake habitats in North Africa, this chain extended as far as Sudan and Senegal, where gyrogonites characteristic of N. obtusa can be found in the fossil state213, 270, 359. Charophytes are still too frequently neglected in the management of wetland habitats although their role as a structural factor has been recognised by many ecologists. Charophyte Red Lists already exist for many European countries, Australia and Japan348, 351, 364, 416. It is now vital that France follows the example of these countries and acts to create a Charophyte Red List and takes efficient measures for the protection of these plants. Soulié-Märsche I.

23

Mediterranean temporary pools

Table 3. Characteristic plants of the temporary pools of Mediterranean France; based on Médail et al.259, modified and added to Agrostis pourretii Willd. Airopsis tenella (Cav.) Asch. & Graebner Anagallis arvensis L. subsp. parviflora (Hoffm. & Link) Arcangeli Anagallis minima (L.) E.H.L. Krause (= Centunculus minimus) Antinoria insularis Parl. Apium crassipes (Koch) Reichenb. fil. Artemisia molinieri Quézel, Barbero et Loisel Callitriche brutia Petagna Callitriche truncata Guss. subsp. occidentalis (Rouy) Br.-Bl. Callitriche truncata Guss. subsp. truncata Cardamine parviflora L. Chaetonychia cymosa (L.) Sweet Cicendia filiformis (L.) Delarbre Crassula vaillantii (Willd.) Roth. Crypsis aculeata (L.) Aiton Crypsis schoenoides (L.) Lam. Damasonium polyspermum Coss. Elatine brochonii Clavaud Elatine alsinastrum L. Elatine macropoda Guss. Eryngium barrelieri Boiss. Exacullum pusillum (Lam.) Caruel Glinus lotoides L. Gratiola officinalis L. Heliotropium supinum L. Illecebrum verticillatum L. Isoetes duriei Bory Isoetes histrix Bory Isoetes setacea Lam. Isoetes velata A. Braun subsp. velata Isolepis cernua (Vahl) Roemer & Schultes (= Scirpus savii Seb. & Mauri) Isolepis setacea (L.) R.Br. (= Scirpus setaceus L.) Juncus bufonius L. Juncus capitatus Weigel Juncus pygmaeus L.C.M. Richard Juncus tenageia L. fil. Kickxia cirrhosa (L.) Fritsch Kickxia commutata (Reichenb.) Fritsch subsp. commutata Littorella uniflora (L.) Ascherson Lotus angustissimus L. subsp. angustissimus Lotus angustissimus L. subsp. suaveolens (Pers.) O. Bolos & Vigo Lotus conimbricensis Brot. Lotus pedonculatus Cav. Lythrum borysthenicum (Schrank) Litv. (= Peplis erecta, P. hispidula) Lythrum hyssopifolia L. Lythrum thesioides M. Bieb. Lythrum thymifolium L. Lythrum tribracteatum Salzm. ex Sprengel Marsilea strigosa Willd. Mentha cervina L. Mentha pulegium L. Moenchia erecta (L.) P. Gaertner, B. Meyer & Scherb. s.l. Molineriella minuta (L.) Rouy Montia fontana L. subsp. chondrosperma (Fenzl) Walters (= M. minor C.C. Gmelin) Morisia monanthos (Viv.) Ascherson Myosotis sicula Guss. Myosurus minimus L. Myosurus sessilis S. Watson Myriophyllum alterniflorum DC Nananthea perpusilla (Loisel.) DC. Oenanthe globulosa L. Ophioglossum azoricum C. Presl. Ophioglossum lusitanicum L. Pilularia minuta Durieu ex A. Braun Polygonum romanum Jacq. subsp. gallicum (Raffa.) Raffa. & Villar Pulicaria sicula (L.) Moris Pulicaria vulgaris Gaertn. Radiola linoides Roth. Ranunculus lateriflorus DC. Ranunculus nodiflorus L. Ranunculus ophioglossifolius Vill. Ranunculus revelieri Boreau subsp. revelieri Ranunculus revelieri Boreau subsp. rodiei (Litard.) Tutin Sisymbrella aspera (L.) Spach s. l. (= Nasturtium asperum (L.) Boiss.) Solenopsis laurentia (L.) C. Presl. Solenopsis minuta (L.) C. Presl. subsp. corsica Meikle Teucrium aristatum Pèrez Lara Trifolium angulatum Waldst. & Kit. Trifolium ornithopoides Oeder Triglochin bulbosum L. subsp. laxiflorum (Guss.) Rouy Verbena supina L. Veronica acinifolia L. Veronica anagalloides Guss.

24

batardae, M. quadrifolia, M. strigosa and Riella helicophylla, and a revision of the Red Lists is also necessary (Boxes 10 and 11). Inclusion in Red Lists or official protection decrees is very inconsistent between countries, and an improved prioritisation at the Mediterranean level of the threats facing these species, based on the current criteria of the IUCN395, is clearly required. At the present time, the latest IUCN Global Red List408 only takes 11 taxa into account, and there are many major omissions. At the national level, the rare books or Red Lists available (Spain, France, Israel, Italy, Malta) highlight the vulnerability of a large number of these plants, with the exception of that for Greece297, which includes only Callitriche pulchra and Pilularia minuta (Tab. 2). Figure 4. Localisation of the important temporary pools for vas-

cular plants in Corsica, grouped into five main sectors (based on Lorenzoni & Paradis, in Médail et al.260). Ephemeral pools, with a very small surface area and present in various places below the ridges of Cap Corse, in Les Agriate and in the north of PortoVecchio, have not been indicated. Cap Corse: 1: Capandola Agriate: 2: shooting range at Casta 3: Taglia Carne (Malfalcu) Around Porto-Vecchio: 4: north of the Etang d’Arasu 5: Mura dell’Unda 6: Alzu di Gallina 7: Muratellu 8: Padulellu Bonifacio area: 9: Tre Padule and Padule Maggiore (Suartone) 10: Rondinara 11: Tre Padule de Frasseli 12: pools to the southeast of Frasselli 13: Padulu and Paraguano pool 14: Musella and east of Musella 15: Cavallo Island 16: Lavezzu Island Southwest coast: 17: Tonnara 18: Ventilegne 19: Testarella 20: Capineru 21: Chevanu 22: Arbitru 23: Tour d’Olmeto and Furnellu 24: Capu di Zivia 25: Cala di Barbaju 26: Senetosa 27: Salina 28: Canusellu

1

3

Saint Florent

•

2

•Bastia

Ajaccio

•

5 4 28 27 26 25 24

6 7

8

21 23 22 2019 11 9 10 18 12 17 13 14 15 Bonifacio 16 Lavezzi Islands

•

2. Biodiversity and conservation issues

Table 4. List of vascular plants, rare, protected or threatened, present within the 20 zones studied in Mediterranean France (based on

Médail et al.260, supplemented by the data of Lewin235, Jeanmonod203 and INFLOVAR195) Noteworthy plants of temporary pools

Protection

Provence - Côte d'Azur Agrostis pourretii Willd. Airopsis tenella (Cav.) Asch. & Graebner Antinoria insularis Parl. Apium crassipes (Koch) Reichenb. fil. Artemisia molinieri Quézel, Barbero & Loisel Callitriche truncata Guss. subsp. occidentalis (Rouy) Br.-Bl. Callitriche truncata Guss. subsp. truncata Cardamine parviflora L. Cicendia filiformis (L.) Delarbre Crassula vaillantii (Willd.) Roth. Crypsis schoenoides (L.) Lam. Damasonium polyspermum Coss. Elatine brochonii Clavaud Elatine macropoda Guss. Eryngium pusillum L. Exaculum pusillum (Lam.) Caruel Gratiola officinalis L. Heliotropium supinum L. Isoetes histrix Bory Isoetes setacea Lam. Isoetes velata A. Braun subsp. velata Kickxia cirrhosa (L.) Fritsch Kickxia commutata (Reichenb.) Fritsch subsp. commutata Littorella uniflora (L.) Ascherson Lotus conimbricensis Brot. Lythrum thesioides M. Bieb. Lythrum thymifolia L. Lythrum tribracteatum Salzm. ex Sprengel Marsilea strigosa Willd. Mentha cervina L. Molineriella minuta (L.) Rouy Morisia monanthos (Viv.) Ascherson Myosotis sicula Guss. Myosurus sessilis S. Watson Nananthea perpusilla (Loisel.) DC. Ophioglossum azoricum C. Presl. Ophioglossum lusitanicum L. Pilularia minuta Durieu ex A. Braun Polygonum romanum Jacq. subsp. gallicum (Raf.) Raf. & Vill. Pulicaria sicula (L.) Moris Pulicaria vulgaris Gaertn. Ranunculus lateriflorus DC. Ranunculus nodiflorus L. Ranunculus ophioglossifolius Vill. Ranunculus revelieri Boreau subsp. revelieri Ranunculus revelieri Boreau subsp. rodiei (Litard.) Tutin Solenopsis laurentia (L.) C. Presl. Solenopsis minuta (L.) C. Presl. subsp. corsica Meikle Teucrium aristatum Pèrez Lara Trifolium angulatum Waldst. & Kit. Trifolium ornithopodioides Oeder Triglochin bulbosum L. subsp. laxiflorum (Guss.) Rouy Verbena supina L.

PACA

x

x x

Languedoc - Roussillon

x 0?

x

Corsica x x x x

x

Corsica - Red data book

x

x

x

x x

x 0?

x x x

x x

x x

x

x x

x

Nat - livre rouge

0?

0 x

PACA PACA, LR Nat Nat - Red data book LR Nat - Red data book PACA Nat LR Nat Nat - Red data book Nat - Red data book Nat Nat Nat PACA, LR Nat - Red data book Nat - Red data book Nat - Red data book Nat - Red data book PACA - Red data book Nat Nat - Red data book LR

0?

x x

x x x

0 0 x x

x

x x

x x

x x

0?

x

x

x x 0?

x x x

x

0?

x

x

x

x

x x

x x

x 0? x x

0

x

0?

x x

0?

x x

x

x x x

x 0?

0 0 0

0 x

0 0

0

x

0?

0 0? x x 0

0

x x

0 0

0

x x

x

0

x 0?

x x

x x

0?

x

x

x x

x

0 x 0

x

x

x

0?

x x x x

x x x

x x

x

x

x 0

x

x x

X x

x

x

x

0 x x

x 0? x

x

0? 0 0

0

x

x x

0? x x

x

x

x x

x x

x

x x x x x

x x x x x

x x x

x x x

x

x

x x x

x

x

x x x x

x

x

x x

x

x x

x 0?

x

x x 0

x

x

x x 0? x x

x

x

x

x

x

x x

x x

x

x x

x x

x x

x x

x x

x

x x

x

x

x x

x x

x

0? x

x

x

x

0?

x

x

x x

x x

x

x

x

0? x

Nat - Red data book LR Nat PACA

x x x

x

x Nat - Red data book Nat - Red data book PACA, LR Nat - Red data book Lang. PACA, LR Nat. Nat - Red data book Nat - Red data book Nat Nat - Red data book Nat - Red data book PACA

0

x x

0 0 x

0 0

x

0?

0?

x

0?

Protection (Decrees of 20/01/1982 and 31/08/1995): National: protected species throughout the national territory; PACA: protected species in Provence–Alpes-Côte-d’Azur; Corsica: protected species in Corsica; Languedoc-Roussillon: protected species in Languedoc-Roussillon; Red Data Book: species included in “Red Data Book of the threatened flora of France, priority species”285. Status: X: taxon currently present at the studied site; 0?: taxon not seen for over 10 years at the studied site; 0: taxon probably disappeared from the studied site.

Conservation issues and levels of protection in Mediterranean France Of the 83 plant species characteristic of temporary pools in France (Tab. 3 et 4), 53 are considered to be threatened in all or part of their French range (Tab. 4). These are mostly protected species (44 taxa in total) whether at a national level (28 taxa) or on the Regional scale in Corsica (1 taxon), LanguedocRoussillon (9 taxa) or Provence-Alpes-Côte d’Azur (10 taxa). It is also to be noted that 20 taxa are listed in the Red Book of the threatened plants of France, priority species285, which illustrates the magnitude of the conservation issues regarding these species and their habitats in Mediterranean France. Based on data available in the literature and provided by field surveys, 20 “key areas” of the French Mediterranean have been selected for their richness in characteristic plants of temporary pools, 15 on the mainland and 5 in Corsica (see Médail et al.,260 for descriptions of the various areas) (Tab. 4, Fig. 3).

The present status of the plant communities of Mediterranean pools gives much more cause for concern in mainland France than in Corsica (Tab. 4). In Corsica (Fig. 4), the overall conservation status of these communities appears to be fairly satisfactory at present apart from the pools of the eastern plain, which have mostly been destroyed or drained, such as those with Eryngium pusillum at Vix or those with Pilularia minuta north of Aléria and near the Tour de Vignale. These examples, admittedly still in a minority, suggest that the degradation of temporary pools can take place quickly at low altitudes and on the coast. The temporary pools of southern Corsica are very rich, with 60% of French rare characteristic species recorded260. The conservation issues in the Bonifacio and Porto-Vecchio areas are particularly acute and are notable in the Mediterranean Basin context242, 291. On the mainland, three groups of pools have practically disappeared or have been profoundly altered by humans: the Saint-Estève pool (Pyrénées-Orientales) has been converted into a permanent pond11; the series of depressions of the Costière

25

Mediterranean temporary pools

Nîmoise (Gard) were drained and brought under cultivation, then completely destroyed during the 1970s; the flooding of the Grammont pool (Hérault) has hastened the disappearance of its characteristic species including Isoetes setacea230. In the AlpesMaritimes, urban pressures encroach further each day onto the Biot Massif, and Pilularia minuta has not been seen for some decades at its solitary site. In 50% of cases in Mediterranean France (Tab. 4), taxa characteristic of temporary pools are categorised as having disappeared (0) or not having been seen for over 10 years (0?) at the site in question. However, due to the adaptations of these plants to spatio-temporal environmental variations, care must always be taken before stating that they have completely disappeared from a site. The example of the recent rediscovery of Marsilea strigosa, Isoetes setacea, Lythrum thymifolia and L. thesioides near the destroyed Saint-Estève pool underlines the key role of the soil seedbank in assuring the medium- or long-term survival of these species.

c. Amphibians Cheylan M.

Introduction The life cycle of amphibians is characterised by a larval stage which makes them dependent on an aquatic habitat, with the exception of some species which are able to give birth to fully developed young (the Black Salamander, for example). This aquatic phase is the first stage of their life, and very different from the terrestrial life of the adults. The larvae of anurans (tadpoles) go through a spectacular metamorphosis resulting in significant morphological and physiological transformations: the development of pulmonary respiration, the growth of legs, resorption of the tail and the transition from herbivorous feeding to an insectivorous regime. This larval stage, which is variable in length, is a key stage for the survival of amphibians, hence the importance of breeding sites for their conservation. It is all the more important if the amphibians are only found at a limited number of sites. Among the numerous aquatic sites in the Mediterranean region, only a few can be used by amphibians. The eggs and larvae are very sensitive to disturbance and predators, which limits the choice of breeding sites. Though some species can reproduce in fast-flowing

Figure 3. Localisation of 15 determinant temporary pool areas for vascular plants, in Mediterranean continental France (based on Médail

et al.260, modified)

ITALY

Avignon Nîmes Montpellier

Nice Arles Aix-en-Provence

Cannes

Marseille

Béziers

Toulon

Mediterranean Sea Perpignan

0

100 km

SPAIN 1: Biot Massif; 2: massifs of the Estérel and the Colle du Rouet and the Plaine de Palayson; 3: Plaine des Maures; 4: pools of the Centre-Var; 5: Plaine de Crau; 6: Etang de la Capelle; 7: Costière Nîmoise; 8: Grammont pool; 9: Agde region; 10: Plateau de Pézenas; 11: Plaine de Béziers; 12: Plateau de Roque-Haute; 13: Plateau de Vendres; 14: St-Estève pool and surroundings; 15: Plateau de Rodès.

26

2. Biodiversity and conservation issues

water (Salamanders, Euproctus), most seek calm waters, usually isolated from the hydrographic network. As a result, temporary pools are preferred breeding places as they are usually isolated and contain few predators (fish, water snakes, birds). These habitats are also favourable from a thermal point of view, and rich in the phyto- and zooplankton consumed by larvae. Unlike fastflowing water, the pools also provide abundant aquatic vegetation, favourable to egg laying. For all these reasons, most species only reproduce in the Mediterranean region in pools, and usually only in temporary pools. These habitats are thus essential for the survival of this group. The breeding cycles show to what extent amphibians have adapted to these habitats, notably through the synchronism between egg laying and submersion periods, which are very irregular in the Mediterranean region (see Chapter 3d).

The threats to temporary pools are numerous (see below and Chapter 4). In this context, amphibians are excellent bio-indicators. They are sensitive to physical disturbances in the habitat (decline in breeding sites) as well as to chemical (pollutants, fertilisers, etc.) or biological (trampling by animals, introduced species, etc.) disturbances. In addition, they are bio-indicators of the terrestrial habitat surrounding the breeding site. Damage to one or more components of the system quickly leads to losses of species or populations. Our knowledge of the biology of Mediterranean species remains limited. Numerous questions remain unanswered, for example about the factors triggering breeding or the terrestrial life of the animals (dispersal distance, type of refuge used, habitat sought, etc.). Important questions can also be asked regarding the viability of populations: what is the distance needed between subpopulations in order for a species to be maintained on a given territory? What exchanges take place between pools? What is the minimum effective number* for an isolated population? Furthermore, very few conservation or restoration experiments have been conducted, other than the research on Triturus cristatus within the context of the LIFE “Temporary Pools” project (see Boxes 26 and 50) and the research carried out in the Balearics on Alytes muletensis332.

What kinds of temporary pools are used by amphibians? Reservoirs, large watercourses and brackish lagoons are rarely if ever occupied by amphibians. Apart from those, amphibians make use of very diverse sites: coastal ponds rich in macrophytes, dune slacks, dayas, watering places, natural depressions on rocky ground, wadis in the process of drying out, artificial basins, abandoned quarries, etc. The temporary nature of the sites is a key factor (see Chapter 3d) for many Mediterranean amphibians. Of the 71 species recorded

Jakob C.

The conservation issues remain poorly understood, notably in the southern and eastern Mediterranean. There are still very few national or thematic studies, apart from some recent studies19, 121, 302, 355. Attempts at more global approaches are often restricted to single European countries85, 91, 192, 225 and there are no Mediterranean action plans for the conservation of amphibians as there are for plants108 or wetlands13. Thus on the basis of the documents available, it is difficult to identify the issues from a geographical point of view, apart from for a very specific region or country.

Juvenile Triturus marmoratus in a pool with Isoetes setacea and Marsilea strigosa (Roque-Haute Nature Reserve, Hérault, France)

in the west of the Basin, 14 species are virtually totally dependent on temporary pools, and temporary pools are the preferred breeding habitat for 25 species (53% of all species, Tab. 5). Most species breeding in temporary pools prefer an open or lightly wooded habitat. The presence of livestock is therefore usually favourable for them.

Richness and diversity of communities The Mediterranean Basin has been recognised as a global biodiversity “hotspot”38, 279, 314 but its batrachian richness remains low because of the climatic conditions, which are unfavourable for this zoological group. With 78 species, this fauna occupies an average position with regard to species richness, on a par with the southwest USA. Compared with tropical regions, this richness is characterised, given an equal number of species, by a greater number of genera and families. Maximum richness peaks at around 50°N latitude156 i.e. outside the Mediterranean zone (northern France and southern Germany). In the Mediterranean Basin, the species richness of amphibians decreases from west to east, in relation to the aridity gradient: 71 species in the west v. 14 in the east78. The countries richest in species are situated in the northwest of the Basin: Spain and the Italian peninsula with 25 species, France and Portugal with 18 species, then the Balkans (11 to 16 species) and finally the Maghreb (7 to 11 species) (Tab. 5). The islands have fewer species (maximum 8 species in Sardinia, minimum 1 in the Balearics if introduced species are excluded). Considering only species dependent on temporary pools, the maximum richness occurs in the western Iberian region (22 species), followed by the Italian region (13 species),

27

Mediterranean temporary pools

Morocco

Tunisia

NT

Algeria

Portugal

VU

Balearics

Crete

Spain mainland

Greece

Albania

Serbia

Macedonia

Croatia

Bosnia-Herzegovina

Sardinia

Slovenia

Sicily

Italy mainland

Corsica

France mainland

Habitats directive

Importance of pools

UICN categories (2001)

Table 5. List of amphibians present in the north and southwest of the Mediterranean region (Cheylan & Geniez, unpublished)

11 3 0

9 0 0

7 0 0

URODELES Proteidae Salamandridae

Plethodontidae

Proteus anguinus

NU VU B1+2bc, C2a

Salamandra salamandra Salamandra corsica Salamandra algira Salamandrina terdigitata Chioglossa lusitanica Triturus cristatus Triturus carnifex Triturus karelinii Triturus marmoratus Triturus pygmaeus Triturus alpestris (incl. cyreni) Triturus vulgaris Triturus boscai Triturus helveticus Triturus italicus Euproctus asper Euproctus montanus Euproctus platycephalus Pleurodeles waltl Pleurodeles poireti

A A A NU NU VU A2c I LR/cd I I D D I I D D D NU A A CR A1ac, B1+2bcd D D

Speleomantes italicus Speleomantes ambrosii Speleomantes strinatii Speleomantes genei Speleomantes flavus Speleomantes supramontis Speleomantes imperialis

NU NU NU NU NU NU NU

LR/nt VU C2b, D2 LR/nt LR/nt

II,IV S S NT 1 II, IV II,IV IV IV IV

V

S IV IV IV IV

VU

K

LC VU VU

NT NT 4

LC LC

NT K

V I

R

NT R NT

IV II,IV II,IV 2 II,IV II,IV II,IV II,IV

R

ANURANS Discoglossidae

Discoglossus pictus (incl. auritus) Discoglossus scovazzi Discoglossus galganoi Discoglossus jeanneae Discoglossus sardus Discoglossus montalentii Alytes obstetricans Alytes dickhillenii Alytes maurus Alytes muletensis Alytes cisternasii

Bombinatoridae Bombina variegata (incl. pachypus) Pelobatidae

Pelodytidae Bufonidae

Exotic species

VU A2c, B2c+3d, C2a

IV

I

IV II, IV II,IV II,IV IV

R

CR B1+2bc

II+,IV IV II,IV

V

IV IV IV

V

Pelodytes punctatus Pelodytes ibericus

D D

V

Bufo bufo (incl. spinosus, verrucosissimus) Bufo mauritanicus Bufo viridis Bufo brongersmai Bufo calamita

I I D I D

S

Rana dalmatina Rana italica Rana graeca Rana latastei Rana iberica Rana lessonae (incl. bergeri) Rana shqiperica Rana epeirotica Rana kl. esculenta (incl. hispanica, maritima) Rana bedriagai (= R. levantina) Rana kurtmuelleri (= R. balkanica) Rana cerigensis Rana cretensis Rana kl. grafi Rana perezi Rana saharica (incl. riodeoroi) Rana ridibunda Rana catesbeiana total indigenous species: 71 species exclusive to the territory introduced species

A A A A LR/nt NU A A A A A A ? A I I I

IV IV 3 IV 3 IV IV IV IV II,IV IV IV

NT VU

NT

NT

NT

NT

NT

M

IV

LR/nt

NT

CR

I

IV

LC NT R R

I

D I D D

I I I I

I(lc)

VU B1+2cd

Pelobates fuscus Pelobates syriacus Pelobates cultripes Pelobates varaldii

Hylidae Hyla arborea Hyla intermedia (= H. italica) Hyla sarda Hyla meridionalis Ranidae

I I I I I A I A I A I

M

LC DD

NT

LC I (nt)

NT

LC

NT

NT

NT

NT

NT

V

I (vu)

S

S S S

?

I

EN

M I?

VU

NT

NT

I

18 0 0

1 1 3

I

V I I?

V

S

LC

V

I

I

I 18 0 5 (6?)

I 6 (7?) 3 1?

25 5 1

I 5 0 0

8 5 1

14 0 0

16 0 0

14 0 0

16 0 0

11 0 0

14 0 0

15 1 0

3 1 0

25 2 3

Importance of temporary pools for species: D: determinant, I:important, A: not essential, NU: not used. IUCN world categories (version 2001395): CR: seriously threatened with extinction, VU: vulnerable, LR: low risk Red Data List categories France256: E: Endangered species, V: vulnerable, R: rare, I: indeterminate status, S: surveillance necessary. Red Data List categories Spain302: DD: insufficient data, CR: critically endangered species, EN: endangered, VU: vulnerable, NT: near threatened, LC: least concern Red Data List categories Portugal141: V: vulnerable species, R: rare, I: indeterminate status, K: insufficiently known, NT: not threatened. Categories for Italy (Environment Ministry): M: threatened I: Introduced species Endemic species 1. Spanish possessions in Morocco 2. as sub species of ambrosii 3. as sub species of arborea 4. as sub species of marmoratus

28

+

priority HD species

2. Biodiversity and conservation issues

North Africa (12 species) and the Balkans (10 species). The fauna of the islands contains few species, in accordance with their surface area (Tab. 6). At a local scale (from 10s to 100s of km2), the species richness can be given for four regions: • In Provence, an inventory of 16 pools in the centre and south of the Var département (Joyeux A., pers. com.) revealed a species richness of between 3 and 6 species (average: 4.5), for a total of 7 species in the whole of the area studied. • In Languedoc, an inventory of 11 temporary pools in the Montpellier region and 16 pools in the Roque-Haute Nature Reserve near Béziers enabled the species richness to be estimated in two distinct geographic sectors. In the first sector, the number of species breeding in a given year in a pool oscillates between 3 and 7, with an average value of around 5.09, for a total of 9 species in the whole of the zone sampled72. In this area there is a single pool containing 7 species, a record number for the region. At RoqueHaute, the number of species oscillates between 2 and 5 per pool, for an overall total of 7 species. The average number of species is between 3.12 (1996) and 3.5 (1997), and around 10 pools are needed to obtain all the species present in a given year200. • In Andalusia (Spain), Diaz-Paniagua116 compiled an inventory of 15 temporary pools in the Doñana Nature Reserve. In this region, the average number of species per pool is 4.6 (min 2, max 7) and between 8 and 10 pools are needed to obtain the 10 species present in the area studied. • In Morocco, El Hamoumi127 compiled an inventory of an ensemble of temporary wet habitats (dayas, gueltas, temporary pools) in the region of Mamora and the Merja Sidi Boughaba. In this case, the average number of species per breeding site was 2.6 (min 1, max 4) and between 4 and 6 pools were needed to obtain the 6 species present in the region. Only Rana saharica was missing from this inventory, in accordance with its preference for wells in this part of Morocco. From these few figures, it can be deduced that on average 10 pools are needed to “capture” all the species present in a given region. A small number of sites are thus sufficient for all the species to be represented. Occasionally, one to two pools can contain almost all the species but these are exceptional cases, due to particularly favourable habitat conditions: a large structurally diverse pool, with no aquatic predators and a long submersion period with brief but regular dry periods. At Doñana, Diaz-Paniagua115, 116 showed that it is the largest and most perennial pools that contain the most species, which is confirmed by the data of Jakob et al.197, 198 at Roque-Haute in the Hérault and by Alcazar & Beja6 in southeast Portugal. For the latter authors, there is also a significant relationship between the length of the hydroperiod* and the number of natural-heritage species, which tallies with the observations made in the French Mediterranean region. The different submersion periods of pools often enable a larger number of species to coexist. Generally speaking, an ensemble of small pools with varied water regimes seems preferable to one single large pool. This diversity of water regimes and ecological conditions (surface area, depth, etc.) gives more stability to the system by enabling greater regularity of breeding for the various species.

region compared with the hotspots of tropical diversification situated to the south of the Sahara and in southeast Asia. • Species endemism here reaches 58.7%, which is higher than most other botanical and zoological groups (50% in vascular plants312, 44% in freshwater fishes95, 46% in butterflie188, 17% in birds38) with the exception of reptiles79 (62%). The main hotspots of endemism are found in the Iberian Peninsula with 13 endemic species out of a total of 30 (43.3%), in Corsica-Sardinia with 9 species out of 12 (75%), in the Italian peninsula with 9 species out of 25 (36%), in North Africa with 7 species out of 13 (53.8%), then in the Balkans with 6 species out of 22 (27.3%). Crete and the Balearics only have one endemic species and Sicily none. In the Near East, 3 species out of 14 are endemic, i.e. 21% endemism. If just the species linked to temporary pools are taken into consideration, the classification is only slightly modified (Tab. 6). In this case, it is the Corsica-Sardinia region which comes first (66.6%) followed by North Africa (58.3%), western Iberian region (36.3%), the Italian region (23%) and finally the Balkans (10%). • The taxonomic diversity of amphibians is also high, with 19 genera, 10 families and two orders, i.e. 4.3%, 22.2% and 66.6% respectively of the global total. The best-represented families are Discoglossidae with 73.3% of global species (11 out of 15), Pelodytidae with 66.6% of global species (2 out of 3), Salamandridae with 35.8% and Proteidae with 16.6% of global species. As regards the genera, 7 of the 19 genera present in the Mediterranean region are strictly endemic: Discoglossus, Chioglossa, Euproctus, Salamandrina, Pleurodeles, Proteus and Speleomantes, and several are mainly found here: Pelodytes, Pelobates, Alytes, Mertensiella and Triturus. Of these, many belong to ancient lineages with a high natural-heritage value. This is the case with: the genus Pleurodeles, which comprises two species belonging to a very primitive group of Salamandrids22; the genus Euproctus, comprising one species in the Pyrenees, one in Corsica and one in Sardinia; the genus Chioglossa, which is distinctly relictual, with only one species in the northwest of the Iberian Peninsula; the genus Discoglossus, endemic in the Mediterranean, with a marked species differentiation in the Iberian Peninsula and the Tyrrhenian islands; the genus Pelobates, sole representative of the family in Europe, with four species more or less exclusive to the Mediterranean region; the genus Pelodytes, sole genus in the family Pelodytidae, today comprising three species of which two are Mediterranean and one Caucasian; the genus Alytes, comprising five species distributed in the west of the Mediterranean, sometimes with very limited ranges such as the Mallorcan Midwife Toad, the Moroccan Midwife Toad and the Cisternas Midwife Toad

The Mediterranean batrachian fauna is highly distinctive, probably due to geographical complexity (numerous islands, peninsulas, mountainous zones) as well as the isolation of this biogeographical

Cheylan M.

Distinctiveness of the fauna, biogeography* and endemism Discoglossus sardus, an amphibian endemic to the French and Italian Tyrrhenian islands

29

Mediterranean temporary pools

found in the southwest of the Iberian peninsula. Several of these ancient lineages are in a phase of decline, i.e. comprising very few species, sometimes only one, often geographically localised and generally monotypic: Proteus, Salamandrina, Chioglossa, Euproctus and Pleurodeles. Others, on the other hand, are diversifying (Speleomantes, Discoglossus, Alytes), which shows that the processes of adaptive radiation do not only involve younger lineages (the genera Rana, Hyla, Triturus for example).

Main threats On the global scale, a rapid and worrying decline of certain amphibian populations has been observed since the 1980s7, 68, 180, 193. It has become manifest in very diverse regions sometimes untouched by human activity: Australia393, Costa Rica237, the former USSR216 and the Pyrenees251. The causes of this decline remain largely unexplained68. Numerous hypotheses have been put forward: climatic changes, epidemics, acidification of habitats, increase of UV-B radiation and the introduction of exotic species, and these hypotheses are undoubtedly not mutually exclusive, as indicated by most recent studies. Up until now, this global decline has only been observed locally in the Mediterranean region: in the Ebro Delta (Santos pers. com.), the Central System in Spain252, 288 and in Portugal6. On the other hand, a study in Languedoc has shown that amphibian populations have remained stable over the last 25 years98. The implementation of biological monitoring thus seems essential, as has been carried out in several regions of the world72.

Conservation issues and protection measures for the western Mediterranean Table 5 presents an up-to-date list of the amphibians present in southern Europe and North Africa. This list is based on an updated compilation, hence the appearance of taxa not listed in some guides. The position of some taxa in the classification has not yet been unanimously accepted and this list could thus be modified in the future. To the 39 species mainly (25 species) or exclusively (14 species) dependent on temporary pools, two species can be added which have recently become established in the region: Rana catesbeiana introduced in 1932 in the Mantova region of Italy and Rana ridibunda introduced into southern France in the 1980s and now in a phase of expansion.

Of these 39 species, 30 merit particular attention due to their rarity or to the threats which they face (Tab. 7). Six of them can be considered as priority species at the Mediterranean scale: • Triturus cristatus is only represented by two isolated populations in southern France, one of which is situated in a zone undergoing urbanisation63. • Pleurodeles poireti is endemic in Tunisia and eastern Algeria. It is a species with a poorly known status, but appears to be threatened in a part of its range (Samraoui, in Morand272). • Discoglossus jeanneae occupies the eastern half of the Iberian Peninsula. Its populations are fragmented and in low numbers in the main part of its range apart from in western Andalusia where the species is still abundant (Martínez-Solano and García-París, in Pleguezuelos et al.302). • Alytes maurus is an endemic Moroccan species, known at only 19 sites in the extreme north of the country (Rift mountain, Bou Naceur massif and Jbel Tazzeka)43. • Pelobates cultripes is endemic in Iberia and southern France where it occupies a fairly wide area. It is a species which is currently in decline, both in the Iberian Peninsula (Tejedo & Reques in Pleguezuelos et al.302) and southern France. In this latter region, it is known in only 100 or so sites (Cheylan and Thirion, in Duget & Melki121) and has disappeared from several localities over the last 20 years. • Pelobates varaldii is only found in Morocco, in the form of discontinuous populations situated on the Atlantic coast, from Larache in the north to Oualidia in the south99. It occupies very populated zones, in which the pressures of urbanisation have already caused the disappearance of several populations (Thévenot, pers. com.). With regard to legislation and the recognition of real conservation status, amphibians are still insufficiently taken into account despite the considerable progress made in recent years. The IUCN Global Red List396 only includes two species with a wide distribution, not threatened on the global scale (Triturus cristatus and Hyla arborea), and does not include endemic taxa with very limited distribution such as Pelobates varaldii or Pleurodeles poireti. The Habitats Directive118 includes 22 species in Annexe IV and 4 species in Annexe II: Bombina variegata, Discoglossus jeanneae, D. sardus and Triturus cristatus. During a seminar on re-establishment projects for amphibian and reptile species held at El Hierro, Canary Isles, in October 1993, a group of experts meeting under the aegis of the permanent committee of the Berne convention established a list of species in need of restoration plans85. The species included

Table 6. Species richness and levels of endemism in the main biogeographical sectors of the western Mediterranean (species solely

dependent on temporary pools) Western Iberian region Italian region Balkans Maghreb Sicily Corsica Sardinia Corsica-Sardinia Crete Balearics

30

area (km2) 561 800 141 500 221 300 597 900 25 500 8 700 23 800 32 500 8 330 4 934

number of species 22 13 10 12 4 3 3 3 2 1

numb. of endemic species 8 3 1 7 0 0 0 2 0 0

endemism (%) 36,4 23,1 10,0 58,3 0,0 0,0 0,0 66,7 0,0 0,0

2. Biodiversity and conservation issues

Pelobates cultripes Pelobates varaldii Pelodytes punctatus Pelodytes ibericus Bufo viridis Bufo calamita Triturus cristatus Triturus carnifex Triturus karelinii Triturus alpestris (incl. cyreni) Triturus vulgaris Discoglossus pictus Discoglossus scovazzi Discoglossus galganoi Discoglossus jeanneae Discoglossus sardus Alytes obstetricans Alytes maurus Alytes cisternasii Bombina variegata

(incl. pachypus)

Pelobates syriacus Bufo bufo (incl. spinosus, verrucosissimus) Bufo mauritanicus Bufo brongersmai Hyla arborea Hyla intermedia (= H. italica) Hyla sarda Hyla meridionalis Rana kl. grafi Rana perezi Rana saharica (incl. riodeoroi)

1

1 1

1

1

1

1

1

1

I

1

1

1

1 1

Endémics

Balkans

Endemics

Endemics

1

Balearics

Pelobates fuscus

1

Crete

Pleurodeles poireti

Sicily

Pleurodeles waltl

Corsica-Sardinia

Triturus italicus

1 1 1 1

Maghreb

Triturus helveticus

D D D D D D D D D D D D D D I I I I I I I I I I I I I I I I I I I I I I I I I

Endemics

Triturus boscai

Endemics

Triturus pygmaeus

Italian region

Triturus marmoratus

Western Iberian region

Pools importance

Table 7. List of amphibians which could be considered as threatened in the western Mediterranean D: Very important; I: Important

1

1 1 1 1

1

1

1 1 1 1

1

1 1

1 1 1 1

1

1 1

I 1 1 1 1

1 1

1 1

1

1 1

1

1 1

1

1

1

1

1 1

1 1 1

1 1

1 1 1

1 1

1

1

1

1 1

1 1 1

1

I I

1

22

1

1

1 1

8 13

3 10

1 12

1

7

4

3

1

2

0

for the western Mediterranean were the following: Triturus cristatus, T. italicus, T. karelinii, Alytes obstetricans (in southern Spain, actually considered as a separate species: Alytes dickhillenii), Pelobates fuscus insubricus and Bufo viridis. On a national scale, Red Lists have been established in a number of countries (France, Spain, Portugal, Italy) but only Spain302 has produced a reference work calling for objective criteria and more detailed knowledge of the status of species. Comparison of the Spanish and Portuguese lists reveals disparities which can be put down more to differences of assessment than to differences in status. Harmonisation of criteria for all the Mediterranean countries would seem to be essential.

Conservation issues and protection measures in Mediterranean France The French Mediterranean region supports 24 indigenous amphibians and three introduced species, currently spreading in the region (Tab. 8). Of these 24 species, at least 14 can be considered as vulnerable or threatened due to very reduced distribution, a decline noticed in recent decades or real threats to habitats. Four species are now particularly in danger: three closely linked to temporary pools (the Crested Newt, the Yellow-bellied Toad and Pelobates cultripes) and one less specifically linked (the Agile Frog).

• The Crested Newt was fairly common in the lower Rhône valley at the beginning of the 20th century. It is today known at only five sites, two recently discovered south of Valence (Blache, pers. com.), one in the Ardèche and two in the lower Rhône valley63. Of these five populations, only one is currently the subject of conservation measures (Valliguières in the Gard), thanks to the inclusion of the site in the Natura 2000 network (See box 26 Chapter 3f). • The Yellow-bellied Toad is a species in severe decline throughout most of its range, and particularly in the French Mediterranean region where it was abundant less than a century ago254. Today, it only survives in the central Durance Valley (20 or so sites in the Embrun-Gap sector14 and in certain parts of the high Ardèche and the Diois90. For the moment, it is not the subject of any conservation measures. • Pelobates cultripes is more widespread, with more than 70 breeding sites in Languedoc, 30 or so in Provence and some sites in the lower Ardèche and southern Drôme. It is nonetheless a threatened species, due to the specificity of its habitats and a very long larval cycle. In Provence, it disappeared from several known sites in the 1970s-1980s, in particular in the Var and the Vaucluse. Fifteen sites are the subject of conservation measures, including several included in the LIFE “Temporary Pools” project: Catchéou and Gavoty pool in the Var, Etang de Valliguières in the Gard, Roque-Haute Nature Reserve in the Hérault80. • The Agile Frog has a relict distribution in southern France. In Provence, it is only found in the crystalline massifs of the Maures, the Esterel and the Rouet and their immediate surroundings (a mainly Permian depression). In Languedoc, it is only found in the forest of Valbonne in the Gard and in the west of the Montagne Noire, in the Aude and the Tarn (Revel, Castelnaudary, Mazamet). It is primarily a woodland species, dependent on old broadleaved forests: Cork Oak, Downy Oak, and Chestnut. Its populations appear fairly stable but given their isolation, the frequency of forest fires and possible competition with the invasive species Rana ridibunda, their future is not assured. Among the species classified as vulnerable, some can be locally endangered. This is the case with Alytes obstetricans in Lower Provence (Var and Bouches-du-Rhône) and Discoglossus sardus on the Ile du Levant. With regard to the conservation issues, great disparities can be observed between the three regions, with an overall satisfactory conservation status in Corsica and a poor conservation status in Provence and Languedoc. In the latter two regions, the coastal zones are the most affected; the habitats they provide are often degraded or in the process of becoming so. The abandonment of farmland is very marked, which contributes to the loss of biodiversity and the transformation of natural areas into artificial areas. Our state of knowledge does not really enable zones with amphibian conservation issues to be prioritised from a geographical point of view. Nonetheless, some sites have emerged: the Plaine des Maures - Bois de Palayson - Plateau de Besse - Flassans complex in the Var, the Alpilles and the Camargue in the Bouchesdu-Rhône, the Causse d’Aumelas and Roque-Haute in the Hérault, the pool at Opoul and around Salses in the Pyrénées-Orientales. In Corsica, the status of amphibians can be considered as satisfactory, despite concerns for Euproctus and the Green Toad374. Aquatic habitats are overall in a good state of conservation, even if threats exist to temporary pools, notably in certain coastal sectors subject to growing urbanisation.

31

Mediterranean temporary pools

Table 8. List of amphibians which could be considered as

Initiatives committed-to or ongoing

Corsica

II,IV

Languedoc

Habitats Directive

LR

Provence

UICN categories (2001)

Pools importance

threatened in the French Mediterranean region

URODELES Salamandridae Salamandra salamandra

A

Salamandra corsica

A

Triturus cristatus

D

Triturus marmoratus

D

Triturus helveticus

D

Euproctus asper Euproctus montanus

IV

NU

IV

A

IV

NU

II, IV

Plethodontidae Speleomantes strinatii

2

ANURANS Discoglossidae Discoglossus pictus

I

IV

Discoglossus sardus

I

II, IV

Discoglossus montalentii

A

Alytes obstetricans

D

IV

I

II, IV

D

IV

VU

I

II, IV

Bombinatoridae Bombina variegata Pelobatidae Pelobates cultripes Pelodytidae Pelodytes punctatus

D

Bufonidae Bufo bufo

I

Bufo calamita

D

Bufo viridis

D

IV

Hylidae Hyla sarda

I

IV

Hyla meridionalis

I

IV

Rana dalmatina

A

IV

Rana lessonae bergeri

A

IV

3

Ranidae

Rana bedriagai

I? I

Rana kurtmuelleri

I?

Rana kl. grafi

I

Rana perezi

I

Rana ridibunda

V V

I

I

total indigenous species

15

14

6 (7)

total vulnerable species

6

5

3

total threatened species

3

2

0

not threatened species

6

7

3

Importance of temporary pool for species: D: very important, I: important, A: accessory, NU: non used not threatened vulnerable

32

threatened I:

introduced

For the moment, there are no concerted initiatives at the Mediterranean level in favour of amphibians. Nonetheless, some countries are committed to conservation initiatives, which are ambitious to a greater or lesser extent. This is the case with Spain, which has just produced a Red Book of the reptiles and amphibians of Spain302 which describes the current status of species on a national and regional scale. For each species, there is information detailing the reasons behind the attribution of its national status (based on IUCN methodology), the biological factors important for its conservation, the threats, and an inventory of the more threatened populations. One chapter summarises the current knowledge of the conservation of amphibians and reptiles, and there is a list of programmes being conducted at the national and regional level. No fewer than 30 programmes are concerned with the amphibians in this list. Among the initiatives committed to, it is interesting to note the experimental creation of pools in the Zamora region within the context of a LIFE project “Cigüeña negra en Los Arribes del Duero”4. The work also puts forward an audit of the situation for each region and a catalogue of the important areas for Spanish herpetofauna, based on a precise methodology. In France, an action plan for reptiles and amphibians was drawn up by the Ministry for the Environment in 1996. It has not yet been put into practice. In the Mediterranean region, there have been two LIFE projects concerned in part with the conservation of temporary pools and the fauna associated with them: the “Conservation of the natural habitats and plant species of priority interest in Corsica” project conducted by the Office de l’Environnement de Corse between 1994 and 1997, and the “Protection of the coastal lagoons of Languedoc-Roussillon” project conducted by the Conservatoire du Littoral et des Rivages Lacustres from 1995 to 1997. Within the context of the LIFE “Temporary Pools” project, an inventory of the temporary pools of Provence and Languedoc-Roussillon is due to start in 2004. It should enable the most important pools for amphibian conservation to be identified. Other studies have also been conducted on some species: the Crested Newt within the context of the LIFE “Temporary Pools” project, Discoglossus for which a restoration plan has been drawn up at the request of the Ministère de l’Ecologie et du Développement Durable, and Pelobates cultripes in Provence. In Italy, a number of regional or local programmes are dedicated to the protection of amphibians12, 335, 355 but there is no national coordination as in Spain. In Portugal, the Instituto de Conservação da Natureza (ICN) has initiated a Red Book of the vertebrates of Portugal which will be accompanied by an atlas of the reptiles and amphibians of Portugal. Under the impetus of the Sociedade Portuguese de Herpetologia, created in 1994, there have been numerous conservation initiatives in this country over the last ten years in favour of amphibians. In the Maghreb countries, we do not have any knowledge of any current initiatives for the conservation of amphibians.

2. Biodiversity and conservation issues

d. Macrocrustaceans

Table 9. Inventory of the macrocrustacean species in the countries of the Mediterranean Basin

Thiéry A. ANOSTRACA Artemia parthenogenetica Barigozzi, 1974 Artemia salina (L., 1758) Artemia tunisiana Bowen et Sterling, 1979 Branchinecta ferox (H. Milne Edwards, 1840) Branchinecta orientalis G. O. Sars, 1903 Branchinectella media Schmankewitsch, 1873 Branchinella spinosa (H. Milne Edwards, 1840) • Branchipus blanchardi Daday, 1908 • Branchipus cortesi Alonso & Jaume, 1991 • Branchipus intermedius Orghidan, 1947 • Branchipus serbicus Marincek & Petrov, 1991 Branchipus schaefferi Fischer, 1834 • Chirocephalus brevipalpis (Orghidan, 1953) • Chirocephalus carnuntanus (Brauer, 1877) Chirocephalus diaphanus Prévost, 1803 • Chirocephalus ruffoi Cottarelli & Mura, 1984 • Chirocephalus spinicaudatus Simon, 1886 (n) • Linderiella africana Thiéry, 1986 • Linderiella massaliensis Thiéry & Champeau, 1988 • Linderiella sp. Streptocephalus rubricaudatus (Klunzinger, 1867) Streptocephalus torvicornis (Waga, 1842) Streptocephalus torvicornis bucheti Daday, 1910 • Tanymastix affinis Daday, 1910 • Tanymastix motasi Orghidan, 1945 Tanymastix stagnalis (L., 1758) • Tanymastix stellae Cottarelli & Mura, 1983 • Tanymastigites mzabica (Gauthier, 1928) • Tanymastigites brteki Thiéry, 1986 • Tanymastigites perrieri (Daday, 1910) • Tanymastigites cyrenaica Brtek, 1972

There is a great diversity of crustaceans in temporary habitats. Microcrustaceans, with an adult size of less than 1 mm, are the main components of zooplankton, with Cladocera (Daphnia), Copepoda and Ostracoda, which are benthic organisms. The macrocrustaceans, with a size of between 1 mm and several centimetres in the case of Notostraca (Triops and Lepidurus), are represented by the Branchiopoda other than Cladocera. Details on the morphology, anatomy and biology of these branchiopods can be found, among others, in Thiéry383 and Dumont & Negrea124. The inventories and species distribution in the countries of the Mediterranean Basin are well known (Tab. 9, second volume). Fifty or so species can be counted around the Mediterranean, with a maximum of 4 to 6 species (rarely 7) coexisting at a single site382, most sites only supporting 2 or 3. The class Branchiopoda (branchiopods) contains several orders (Tab. 10): • The order Anostraca, predominant as regards number of species, with three main families: – Branchipodidae, represented by the sole genus Branchipus, B. schaefferi being the common species in the Mediterranean Basin, – Tanymastigidae, with the genera Tanymastix, (T. stagnalis with a wide distribution, T. stellae endemic to Corsica-Sardinia, T. motasi endemic to Romania) and Tanymastigites in North Africa, – Chirocephalidae, with Chirocephalus diaphanus, very common and abundant in the Mediterranean Basin, and the genus Linderiella, represented by three endemic species (Provence-France, Spain, Middle Atlas-Morocco).

NOTOSTRACA Lepidurus apus lubbocki Brauer, 1873 Lepidurus couesii Packard, 1875 Lepidurus apus apus (L., 1758) Triops cancriformis mauretanicus (Ghigi, 1921) Triops cancriformis simplex (Ghigi, 1921) Triops cancriformis cancriformis (Bosc., 1801) Triops numidicus (Grube, 1865) SPINICAUDATA • Cyzicus bucheti (Daday, 1913) • Cyzicus grubei (Simon, 1886) Cyzicus tetracerus (Krynicki, 1830) Eoleptestheria ticinensis (Balsamo-Crivelli, 1859) Imnadia yeyetta Hertzog, 1935 Leptestheria dahalacencis (Rüppel, 1837) Leptestheria mayeti Simon, 1885 Limnadia lenticularis (L., 1761) • Maghrebestheri maroccana Thiéry, 1988

• The order Notostraca is only represented by a single family, Triopsidae, with the genera Triops and Lepidurus. • Representatives of the order Spinicaudata are rarer, with sometimes very localised populations, as is the case in Provence where only two sites are known for Cyzicus tetracerus, two sites for Imnadia yeyetta and one site for Eoleptestheria ticinensis, while, for example, Chirocephalus diaphanus and Branchipus schaefferi are known on tens of sites.

LAEVICAUDATA Lynceus brachyurus Müller, 1776 (n) NB: All the species mentioned depend on temporary pools with the exception of the species of the genus Artemia, which are dependent on salt marshes

Because of their origins which go back to the Devonian383, the branchiopods are fascinating for their primitive morphology and morphological stability to the extent that they have been incorrectly described as “living fossils”. Their highly resilient eggs

• Endemic species (n) Species of northern France

Table 10. Number of branchiopod species in some Mediterranean countries (based on the data of Alonso8, Gauthier159, 160, Cotarelli &

Mura93, Samraoui & Dumont340, Thiéry379, 380, 381, Brtek & Thiéry65, Petrov & Petrov296, etc.) Anostraca Notostraca Spinicaudata Laevicaudata* Total Endemic

Portugal 3 2 2 0 7 0

Spain 11 3 4 0 18 3

France 12 2 4 1 19 2

Italy 13 4 5 0 22 5

Malta 2 1 1 0 4 0

Yugoslavia 10 2 4 0 16 4

Morocco 11 4 4 0 19 6

Algeria 11 3 3 0 17 2

Tunisia 6 2 2 0 10 0

Israel 7 2 5 1 15 0

* Laevicaudata are Palaearctic species present in the northern part of some countries of the Mediterranean Basin.

33

Mediterranean temporary pools

(see Box 32 Chapter 3b) are good markers in the monitoring of ranges. The species of the genus Linderiella, for example, illustrate continental drift. On the European, American and African continents, there are five endemic vicariant* species of temporary pools living in a Mediterranean climate (L. Africana, L. sp. in Spain, L. santarosae and L. occidentalis in California, and L. massaliensis in Provence) which all derive, by allopatric speciation*, from a parent species. Cases of endemism are possible as for the genus Tanymastigites confined to North Africa (five species listed). The Balkans and mountainous regions, because of their isolation during the Quaternary, are also hotspots of endemism65 for several genera (Branchinecta, Branchipus, Tanymastix, Chirocephalus of the spinicaudatus group). These species, which have survived various climatic crises without real damage, are currently at the mercy of anthropogenic actions. The main threats are the introduction of fish (for example, frequent introduction of Pumpkinseed Sunfish, Lepomis gibbosus, Mosquitofish, Gambusia affinis, etc.), the destruction of sites (fillingin, digging out), and modifications to the chemical composition of water which can inhibit hatching during submersion periods. In all cases, populations separated from each other by fragmentation of their distribution areas are weakened by the reduction of interchanges between them (connectivity*). From a scientific point of view, the branchiopods are the choice subjects for the study of metapopulations*, the understanding of genetic stability within populations, the diapause* phenomena of resting eggs, ecophysiological adaptations in response to anoxia*, thermo-tolerance (secretion of protective proteins: HSPs), etc.

Roché J.

For all these reasons, the branchiopods are true symbols of temporary pools. They should be the object of conservation measures and afforded protection status as is the case in California133 and Malta224.

Triops cancriformis, a flagship crustacean of temporary pools

34

e. Insects Thiéry A. The entomological fauna of the temporary pools of the Mediterranean Basin is now broadly known. Among the major groupsa regularly colonising these habitats, the following can be found: • Ephemeroptera with two genera, Cloeon and Caenis, • numerous Odonata (dragonflies), with Zygoptera (Lestes, Ischnura, Coenagrion) and Anisoptera (Sympetrum, Aeschna, Anax, Crocothemis, etc.), • numerous Heteroptera (water bugs): Notonecta, Plea, Sigara, Corixa, Micronecta and Gerris, • Coleoptera: Dytiscidae (Dytiscus, Agabus, Noterus, Coelambus), Gyrinidae (Gyrinus), Helophoridae (Helophorus, Berosus, Hydrous, Anacaena), Haliplidae (Haliplus), etc., • some Trichoptera (Limnephilus, etc.), • Diptera, mainly represented by the Chironomidae, Ceratopogonidae and Culicidae. Ephemeroptera, Odonata, Trichoptera and Diptera are only present in water in the larval form; Heteroptera and Coleoptera, on the other hand, also the use the habitat in the adult state (imagos). In all cases, the biological cycles of the insects include an aerial phase and an aquatic phase, unlike those of the crustaceans of permanent aquatic habitats (Cladocera, Copepoda, etc.), all the life stages of which occur in aquatic habitats. From the biogeographical point of view, the majority of insects inhabiting the temporary habitats of the Mediterranean region are of Palaearctic origin, including those of North Africa. Endemic species are very rare, and most species have fairly extensive ranges. The composition of the insect communities of temporary pools is very variable and to a large extent determined by the hydrology of the habitat. The number of species of insects increases with the duration of submersion (Tab. 11): • If the habitat is ephemeral, only some generalist* Diptera are found, with short life cycles, such as the chironomids and some culicids (mosquitoes). These species interact only very little with the crustacean fauna which is dependent on this habitat (Chapter 2d): the system functions with isolated entities, with no trophic* interactions. • When the submersion period is longer, colonisation by some insects can be seen (Ephemera: Cloeon, hydrophilid Coleoptera: Berosus, Helophorus, dytiscid Coleoptera: Coelambus, Agabus); usually herbivores or detritivores. These insects may lay eggs in the pool allowing the invertebrate community to become more complex. • When water remains in the pool for several months, a second wave of colonising insects, often predators, arrives: the Odonata, Heteroptera (Notonecta, Plea, Corixa, Sigara) Coleoptera (Gyrinus, Gerris, Dytiscus). In these pools with a long submersion period, the species richness increases and trophic chains diversify. A massive arrival of insects is explained by migratory flights, described, for Coleoptera, by Fernando139, Fernando & Galbraith140,

a. For the taxonomic identification of insects see Tachet et al.368 which covers all the Mediterranean Basin. For Odonata see D’Aguilar & Dommanget101 and for Coleoptera Franciscolo150 and Pirisinu301.

2. Biodiversity and conservation issues

The richness and diversity of entomological fauna also depends on the development of macrophytes, the dissolving of organic material, the development of microbial populations, etc. Though most insects colonise varied habitats, some are dependent on a habitat, a type of vegetation or a plant species. The Coleoptera of the genus Haliplus feed on the calcified branches of Characeae. Some Odonata are also dependent on macrophytes, plants with floating leaves347 or plants immersed in stagnant water255. In Provence, the terrestrial coleopteran Agrilus lacus is strictly dependent on Artemisia molinieri, and is thus endemic, as that is, to three temporary pools. Some particular adaptations enable certain insects to survive in temporary pools. Some species can burrow and subsist, in a state of reduced activity, in sediments in adult or larval form. The Coleoptera Helophorus and Berosus reach a depth of 3 to 6 cm in sediments with a water content of around 40 to 50%. In the case of larval burrowing, larvae can pupate in a dry location, for example Berosus guttalis376, or survive for several weeks until the

pool is submerged again, for example the anisopteran Sympetrum striolatum190, and the chironomid Polypedilum pharao375. Insects are an important part of aquatic biocenoses. Whether in Morocco380 or Provence372, 386, they constitute from 60 to 70% of the total number of species present over a complete hydrological cycle (for example, 118 insects out of 143 invertebrates in southeast France or 60 to 76% for pools in the arid zone of Jbilets, near Marrakech, Morocco). The Odonata of temporary habitats may only be transient (the aeshnid Anisoptera which can cross the Mediterranean) or may be dependent on temporary pools (around 20 species). These latter are adapted through their short biological cycles, with rapid larval development. Certain species also have an optional embryonic diapause341 which enables them to adapt to the unpredictability of the habitat. These are some Lestes (L. viridis, L. barbarus), Libellulidae such as Tanetrum fonscolombei (syn. Sympetrum fonscolombei), some Sympetrum (S. sanguineum and S. striolatum found at Lanau, in the poljés of the Var, etc.) or Crocothemis erythraea. Generally speaking, diversity of vegetation is one of the factors determining the number of species of Odonata of a pool120. Though the Zygoptera, because of their jerky flight, do not cover large distances, the Anisoptera, in contrast, have more homogenous distributions and cover larger areas229. In addition to the aquatic insects sensu stricto, a large number of insects living on the surface of the water, in vegetated fringing zones, etc. increases the species diversity of these habitats. The importance of these insects in the functioning of these habitats is described in Chapter 3e.

Papazian M.

Landin220, Landin & Vepsäläinen221. Numerous factors influence the migratory movements of insects: • Meteorological factors (sunshine, clouds, temperature and air humidity, winds). Colonisation experiments in artificial basins, conducted by day and by night, have shown that large Coleoptera (Agabus, Acilius, etc.) migrate on nights when there is a full moon, that the chironomid Diptera migrate regularly in overcast weather, while Notonecta (Heteroptera) prefer to migrate in sunny weather (Thiéry, original data). Incident light plays an important role in the recognition of water bodies and thus in the colonisation of temporary habitats (triggering a descent reflex after visual stimulation). Generally speaking, wind speed constrains migration. • These meteorological factors can be associated with biotic factors such as the growing density of populations when the drying out comes to an end. This density increases the frequency of contact between individuals and triggers migration flights in Sigara for example. • Migration also depends on ecophysiological factors within populations. Some species have an anatomical polymorphism, of genetic origin, which determines the development of the musculature of the wings and thus their aptitude for flight. In corixid Heteroptera Corixidae415 and Gerridae, for example, cases of atrophied musculature or wing reduction are frequent in permanent habitats. In temporary pools, on the other hand, forms with complete wing musculature have a certain selective advantage for colonisation and migration according to whether the habitat conditions are favourable or unfavourable. During periods favourable to migratory flight (appropriate air temperature), the colour of the water appears to influence the colonising species. This colour corresponds to the amount of dissolved and suspended mineral and organic material, and thus to the time elapsed since the flooding of the pool380.

Ischnura pumilio: its biology and ecology enable it to colonise temporarily flooded habitats with ease

Table 11. Diversity of Odonata (Zygoptera and Anisoptera), Heteroptera and Coleoptera in relation to the duration of submersion of the

pool (based on Thiéry375, 380; Terzian372) Ephemeral pool Provence (Esterel, France) Duration of submersion (in months) Number of species of Odonata Number of species of Heteroptera Number of species of Coleoptera

1 0 2 3

Temporary pool Jbilets Marrakech (Morocco) 4 2 9 22

Lanau pool (Crau, France) 6 8 18 47

Bonne Cougne long submersion pool (Provence, France) 8 14 17 13

35

3. Ecosystem and population functioning and dynamics a. Introduction Gauthier P. & P. Grillas The essential ecological characteristic of temporary wetlands is the alternation of flooded and dry phases. During each of these phases, various environmental factors play an important role in the structure and dynamics of these ecosystems. During the flooded, aquatic phase there is poor availability of dissolved oxygen and carbon dioxide for the plants which, to compensate for these disadvantages, have developed anatomical and physiological adaptations (serrated leaves, reduction of cuticle thickness, use of carbonates instead of CO2 for photosynthesis, etc.). During the dry phase (summer), the dryness of the soil is a very important limiting factor for the survival of organisms. It is linked to the thickness and nature of the sediment (useable water reserves for plants, damp refuges and crevices for the animals to retreat into). Several ecosystems could indeed be said to occupy the same place in turn via a succession of phases: the first submerged, with floating plants and swimming animals, followed by a progressive drying-out phase with amphibious plants, then a dry phase with terrestrial vegetation and fauna. A second important ecological characteristic of temporary pools in a Mediterranean climate is the great interannual variation in rainfall (frequency and intensity) resulting in unstable submersion conditions (see Chapter 3b). This succession of contrasting phases which varies from year to year favours the emergence of varied and specialised plant and animal communities which are particularly adapted to the instability of the habitat157. In plants, annual species are favoured as well as perennial species with anatomical structures enabling them to withstand the dry phase260: bulbs of geophytes* (Isoetes setacea, etc.) and the fleshy roots of hemicryptophytes* (Mentha pulegium, etc.). Other environmental factors such as the level of calcium and nutrients* (nitrogen, phosphorous) are fundamental to the functioning of these temporary habitats. Many plants do not tolerate the presence of calcium, the concentration of which determines the establishment of major vegetation types. For example, habitats poor in limestone and more generally in dissolved elements are favourable to formations of Isoetes. Formations of Heleochloion (Heliotropium supinum, Crypsis schoenoides, etc.), on the other hand, are often encountered on limestone-rich substrates. Similarly, crustaceans need calcium to build their carapace. Eutrophication of natural (the accumulation of plant debris) or anthropogenic (input of fertiliser) origin can upset the balance of communities and lead to their banalisation, i.e. the replacement of the characteristic species by more productive, nonspecialised species (reeds, Scirpus, etc.). The eutrophication of water, combined with the phenomena of filling-in by fine or large soil particles (aggradation*), also favours habitat closure by woody species. This process leads not only to an increase in competition for light among plants but can also modify the duration of flooding

36

(via evapotranspiration) and the temperature of the pools, which affects the flora and fauna. Other phenomena such as sedimentation or, inversely, erosion modify the hydrological regime of pools and temporary streams. Another essential factor for the plant and animal populations dependent on temporary pools is their discontinuity. Their dispersal at the scale of the Mediterranean Basin and their scattered distribution within the same region create very isolated habitats. The species occupying these habitats thus appear in the landscape in the form of fragmented populations within a matrix of natural (dry grasslands, maquis or forests) or anthropogenic (fields, vineyards, etc.) habitats. The subjugation of species to environmental constraints varies in relation to their life strategies and their mobility. Certain species complete their entire life cycle in these habitats (plants and crustaceans, for example). Others must of necessity complete a phase of their life there (amphibians, for example). More opportunistic species are not dependent on temporary habitats but profit from temporarily favourable conditions to complete a part of their cycle there (dragonflies for example). Converging life strategies have sometimes evolved in plants or animal species of temporary habitats, including a great adaptability in the life cycle in response to modifications in the habitat18. Thus, for example, when water levels are reduced in the spring and the water temperature increases, development is accelerated in some invertebrates or amphibians (advanced metamorphosis) and plants (the early flowering characteristic of species known as ephemerophytes*). Annual plants and crustaceans have recourse to drought-resistant reproductive organs, seeds or oospores* for the former and eggs or cysts for the latter. These organs constitute “banks” in the sediment enabling them to respond to unpredictable factors in the habitat by ensuring a stock that germinates or hatches, not simultaneously but over a number of years. In amphibians, the adult lifespan means that they need not attempt to breed in years when hydrological conditions are unfavourable.

3. Ecosystem and population functioning and dynamics

b. Hydro-climatic characteristics Chauvelon P. & P. Heurteaux

The volume of water in a pool varies, partly in relation to the inflow of rainwater (direct or indirect) and underground water, and partly in relation to losses by evaporation, overflow or infiltration. The rains falling in the catchment area follow three routes: they evaporate, flow over the surface or infiltrate the soil. The proportion which follows each of these routes depends on the nature of the substrate, the topography and the plant cover. Losses into the atmosphere (in the form of water vapour) are due either to vaporisation from wet substrates (open water, soil and canopy dampened by the rain) or plant transpiration. Together, these two phenomena are known as evapotranspiration. Its importance is in relation to the density and nature of the plant cover of the catchment area. Run-off and infiltration depend on the permeability of the substrate and the slope. For example, run-off is greater on sloping compact rock, whereas infiltration is greater on a porous rock with shallow slopes. In the natural state, the seasonal and interannual variations in the volume of water stocked in a pool result from temporal variations in the ratio/balance of inflows (direct rains, surface run-off, inflow of underground water) and outflows (infiltration, overflow and evapotranspiration). This natural state can be perturbed by humans (irrigation, drainage, domestic uses, for example).

Catard A.

In temporary pools, as in all wetland biotopes, water is the most essential, most formative element for the functioning of ecosystems. Temporary pools are characterised by fluctuations in water levels (Fig. 5) which determine ecological factors such as the duration of flooding, the dates of flooding and drying out, and depth.

The two extreme ecophases (flooded and dry) of a temporary Mediterranean pool (Plaine des Maures, Var, France)

Depending on the geological and geomorphological context, a great diversity of hydrological regimes is encountered (Fig. 6). To identify to what major type of hydrological regime a given pool

Stock = [rainfall (direct + run-off)] – [evaporation of the open water + transpiration] ± underground water ± anthropogenic actions

Figure 5. Variation in water levels in the temporary marshes of Cerisières Sud (Camargue) and in a marsh in the Marrakech region (based on Grillas & Roché175, added to)

La Cerisière sud marsh Camargue, France 1991-1992

1992-1993

1993-1994

1994-1995

Wetland near Marrakech Morocco 1980-1981 1981-1982 1982-1983 1983-1984 1984-1985

1995-1996 60

70

Water level (cm)

Water level (cm)

80 60 50 40 30 20

50 40 30 20 10

10 0 S N J M M J S N J M M J

S N J M M J

Months

S N J M M J

S N J M M J

0

S N J M M J S N J M M J S N J M M J S N J M M J S N J M M J

Months

37

Mediterranean temporary pools

conforms to, the different hydroclimatic processes involved in this regime must be characterised and quantified. It is a difficult undertaking, each case being unique not only because of the physical parameters characterising the pool and its environment but also because of the practical problems and budgetary constraints with which the manager is confronted. Hydrometric equipment is expensive and the cost of hydrological and hydrogeological studies is always relatively high, thus too often difficult to finance. The nature of the data to collect is very varied:

The geographical context A reliable and updateable description of the physical and geographical characteristics of the system being studied must be made. The following is a non-exhaustive list: topography, geology, pedology and land use. Often, in the particular context of wetland areas, knowledge of certain characteristics of the socio-economic system can prove to be essential: agricultural practices in relation to water management, inventory and methods of managing the hydraulic infrastructures.

Figure 6. Typology and hydrological functioning of temporary pools

rivulet Surface run-off dominant

Overflow of rivulets on an impermeable rock

Hydrological basin catchment different from the surface water catchment area

Small cupules on impermeable rock

Surface reservoirs in a karst system

38

Boundary of the surface water catchment Run-off Water input from groundwater Water loss towards groundwater Permeable substrate Impermeable bedrock Marl Limestone Impermeable rock

3. Ecosystem and population functioning and dynamics

Hydroclimatic regime As the basic issue in hydrology in the broadest sense, i.e. including hydrogeology, consists in knowing the distribution and quantifying the terms of the hydrological balance, as much climatological data as possible, which must be as accurate as possible, needs to be gathered. It is essential to know: • the temporal distribution of rainfall because of its incidence on the submersion of the aquatic habitat studied and significant consequences for its biological communities, • the climatic factors determining the evaporating power of the atmosphere such as the saturation deficit, the air temperature, solar energy radiated (or the duration of insolation) and the wind speed. Evaporation of open water and plant transpiration increase with the evaporating power of the atmosphere. The evaporation of open water is even higher if the thermal inertia of the water body is low (pools in drying-out phase). In addition, plant transpiration depends on the degree of humidity of the substrate and on the species and its stage of development.

pool does not require intimate knowledge of the relationship between underground water and surface water. Usually all that is needed for a “health check-up” of these to be made, is to regularly follow the progression of easily measurable parameters (water cycle, physicochemistry). Knowing the influence of underground water is nonetheless essential in some cases, notably in relation to the physical planning of a water body, or to assess the consequences of human activities on the catchment area. In this case, it is advisable to call upon the services of a research consultancy or specialist university laboratory. An initial approach can be made using relatively simple methods and will enable the necessity of starting further research to be assessed. A network of piezometers (see Chapter 6b) will provide information on the dynamics of underground water. However, their installation can prove to be difficult because of the nature of the terrain and the risks of vandalism. In certain cases, simply the variations in the level and/or the electrical conductivity of the surface water will clearly reveal the involvement of underground water in the water cycle of a pool (Box 12).

Underground water Important factors for the biology Underground water occupies the gaps in porous rocks. It includes the capillary water of the aeration zone of the ground which is the reservoir drawn upon by vegetation and, deeper down, the groundwater. The interface between the saturated zone and the unsaturated zone forms the piezometric surface. In a permeable or semi-permeable habitat, the surface water and underground water are interconnected and are involved in interchanges. Depending on the magnitude of inputs due to infiltrations of rainwater and of losses by evapotranspiration from the ground, the position of the piezometric surface varies in relation to the bottom of the pool. The pool will tend to supply the groundwater if the piezometric surface is situated under the bottom of the pool. If it is situated above the level of the open water, the groundwater will tend to supply the pool until the levels are balanced. For intermediate levels between the bottom and the water of the pool, the pool will supply the groundwater to a greater or lesser extent depending on the permeability of the land. Underground water cannot be seen. To study its dynamics, procedures and measuring equipment need to be put in place which are often sophisticated and expensive and only available to specialists. Fortunately, satisfactory management of a temporary

For a full understanding of the biological phenomena in pools, a great number of variables are likely to be important. They should be prioritised according to local situations. • When the topography is known, the volume of water is assessed by the regular measurement of the level and thus gives information about the dates of flooding and of drying out (duration of submersion) which are the most important factors for the living organisms. • The hydric state of the sediments which have gradually emerged is a factor upon which the survival and development of individuals (fauna and flora) after drying out depends. • The chemical composition of the water is always an important factor for fauna and flora. In addition to the usual physicochemical characteristics (temperature, pH, dissolved oxygen, electrical conductivity), the ionic composition of the water can affect the presence or abundance of certain species. In this respect, the lithology of the catchment area and the bottom of the pool (granite, schist, limestone, etc.) is a good indicator which can be confirmed by an analysis of the ionic balance by a specialist laboratory.

39

Mediterranean temporary pools

Box 12. An example of involvement of underground water

As the bottom of the two pools was impermeable, the activity of rain and evaporation alone was not enough to explain the difference in behaviour of the two pools during the spring. Furthermore, a hand auger bored into the marl at the bottom of the “Large pool” remained empty of water whilst another auger on the edge of the “Pool of the newts” filled with water up to the level of the pool.

in the seasonal cycle of a temporary water body: The Etang de Valliguières (Gard) The problems of water supply to the pool were dealt with in 4 successive phases: Preliminary study of existing documents: topographical and geological maps, aerial photos, reports of hydrogeological survey The depression of Valliguières is located in the centre of a broad karstified limestone plateau (Cretaceous period). It is bordered by high, fairly steeply sloping rock faces, faulted at their base. The presence of water in the depression is attested to by the existence of a large spring (which provides water for the village), of seepages marked on the IGN topographical map, and by the brook of Valliguières. The Etang de Valliguières occupies a low area of around 2 ha at the foot of the rock face to the east of the depression.

A working hypothesis The seasonal hydrodynamics of the Etang de Valliguières is not directly governed by the action of rain and evaporation on the level of the water body itself, but indirectly by means of the underground water of the limestone plateau which overhangs it. The water body is supplied by seeping from the karstic aquifer which penetrates the marl stratum by force through fissures at the foot of the rock face. Surveys on the ground (2000-2002) confirmed this hypothesis. • Monitoring of water levels (Fig. 7) Comparison of the actual change in water level with what would have resulted just from the balance of rainfall contributions and losses by evaporation showed a very clear discrepancy between the two. The levels calculated were generally higher than those measured in the period when there was a drop in the water level of the water body and lower in the period of flooding. The water level range* can exceed 5 m. • Monitoring of the electrical conductivity of the water Generally speaking, the conductivity of the water is higher in a period of flood (as a result of the input of the more mineralised water of the karstic aquifer) than in the period when there is a drop in level (no karstic input). The conductivity in the high water period is comparable to that of the spring supplying the village (0.7 – 0.8 mS.cm-1 at 20°C). • The pool-karst complex functions according to the principle of communicating basins (Fig. 8).

Preliminary field observations, late April 2000 The Etang de Valliguières is an endorheic* temporary water body which neither receives from nor supplies a stream. The limestone bottom of the water body is covered with a layer of fairly pebbly impermeable marl of variable thickness. Two old watering places, dug out by humans, are the last holes to hold water before the summer drought when it occurs. One (called below “Pool of the newts”) is built up against the rock face, the other (known as the “Large pool”) is further away. Information from the local inhabitants indicates that the water regime of the Etang de Valliguières tallies with that of the rains. It remains flooded in very wet years and dries out earlier or later in the spring in dry years. However, field observations, added to the features shown on the maps (spring, etc.), has led to another hypothesis of being put forward other than simply the opposing effects of rain and evaporation. In late April 2000, there was around 25 cm of water in the “Pool of the newts” whereas the “Large pool” had already dried out.

Heurteaux P. & P. Chauvelon

Figure 8. Interpretation of the seasonal dynamics of subterranean waters and water bodies (based on Heurteaux186)

Situation end of July 2000

h

D

Grande mare

D

Situation March 2003

Mare aux tritons dry

Grande mare

Mare aux tritons

Situation end of April 2000

h

h

Karst

Pond

Karst

■ Barremian Limestone ■ Water of karstic origin ■ Marl ■ Water arising from saturated marl D drilling ■ Pond floodwater

40

Pond

Karst

Pond

h Loss of hydraulic pressure caused by friction forces which counteract the rise of water in the layer of marl at the bottom of the pool

3. Ecosystem and population functioning and dynamics

Box 13. An example of complex functioning: the Bonne

Cougne pool (Var) The temporary Bonne Cougne pool has a water supply which gives it a distinctive hydrological regime. This results in both floristic1, 361 and faunistic204, 386 richness. A bimonthly analysis of the physicochemical quality of the water throughout a hydrological cycle has enabled the origin of the water and its changes over time to be determined130. Four phases can be distinguished (Fig. 9): Phase 1: after the drying-out period corresponding to the dry summer season, the biotope is flooded by surface run-off water. Water chemestry is characterised by a low degree of mineralisation (C20 <250 µS.cm-1) and a calcium bicarbonate facies. Phase 2: around 2 months later, the karstic aquifer begins to flow and contributes to the pool’s supply; its water is clearly more mineralised (C20 600 to 750 µS.cm-1) with a raised sulphate level. The beginning of the mixing of the waters can be seen.

Phase 4: the supply is reduced and dries up, and the pool closes (water no longer overflows). Lowering of the water level occurs only by evaporation, the lake bottom being totally impermeable. Mineralisation of the water increases naturally by evaporation. However, a distinctive feature is noted with regard to certain ions, such as the strong reduction in calcium and sulphate levels, the result of intense biological activity linked to the growth of Characeae (the precipitation of calcium carbonates was described by Levy & Strauss233). In the Bonne Cougne pool, the populations of Chara vulgaris, C. contraria and C. connivens form dense beds, with a biomass able to reach 300 to 550 g of dry matter per m2. Note that in addition to Characeae, Ostracoda (mainly Cypris bispinosa and Eucypris virens), crustaceans with calcified valves, contribute to the removal of calcium from the water. The conjunction of successive abiotic factors (surface run-off collecting the water from the topographic basin, then input from the underground water of the karst) and biological control (growth in the Characeae precipitating the carbonates) give this Mediterranean temporary ecosystem a unique regime.

Phase 3: less water overflows. The mixing of the two types of water becomes more marked.

Emblanch C. & A. Thiéry

Figure 9. Diagram of the mixing of the waters at Bonne-Cougne

Phase 1 Run-off Overflow

Flooding: December 2001 Phase 2 Run-off

Overflow

Karst water

Figure 7. Monitoring of water levels at the Valliguières pool

January-February 2002

■ 2000 ■ 2001 ■ 2002

■

Measured

■

Calculated

3

Phase 3 Run-off

Water depth (m)

2,5 2

Overflow

Karst water

1,5

March-April 2002

1 0,5

Phase 4

0

-1

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan

-0,5

May 2002 at the drying out

41

Mediterranean temporary pools

c. Vegetation

Zonation

Gauthier P., P. Grillas, V. Hugonnot & J.P. Hébrard The hydrological regime of the pools, with a range of variables such as water level, duration of flooding, dates of filling with water and of drying out, is the essential factor determining the distribution and characteristics of the vegetation. Other factors are discussed using a typological approach (characteristics of the substrate, Chapter 2a) and in the chapter dealing with the effects of human activities (nutrients, pollution, grazing: Chapter 4).

Water levels and vegetation structure In a given pool the spatial and temporal distribution of the vegetation is primarily determined by the water-depth gradients and the duration of flooding. Over a hydrological cycle the vegetation of temporary pools will be successively dominated by different types of plants: aquatic species during the flooded phase, followed by amphibious plants as the pool is drying out and finally terrestrial plants during the dry phase (Box 14). This succession is subject to variations between years: in very wet years aquatic plants will develop more, to the detriment of terrestrial or opportunist species. Similarly, the spatial distribution of the vegetation, in the form of belts, is also determined to a large extent by hydrological gradients.

The topographical gradients in the pools correspond to gradients in the duration and depth of flooding242. The vegetation in the pools is organised principally along these gradients (Box 14).

Box 14. Vegetation zonation in a Moroccan pool In Moroccan pools three zones (three belts) are often recognised (Fig. 10): • A central zone, where communities of aquatic annuals (Nitella translucens, Callitriche brutia, etc.) are replaced, in spring, by communities of amphibious annuals or perennials (Illecebrum verticillatum, Isoetes velata, etc.), and then in summer by communities of hygrophilous* terrestrial annuals (Heliotropium supinum, Pulicaria arabica, etc.). • An intermediate zone, where perennial species (Scirpus maritimus, Eleocharis palustris, etc.) form a mosaic with annuals (Lotus hispidus, Lythrum borysthenicum, etc.). • An outer zone which dries out more quickly, supporting mesohygrophilous* vegetation. It includes characteristic annual amphibious species (Juncus capitatus, J. pygmaeus, Pilularia minuta, Elatine brochonii, etc.), or geophytes* (Isoetes histrix, etc.), more generalist* species (Polypogon monspeliensis, etc.) and sometimes terrestrial woody plants (Cistus spp, Cynara humilis, Asphodelus microcarpus, etc.). Rhazi L. based on Rhazi et al.326 ; Rhazi et al.327

Figure 10. Zonation of the vegetation in the Benslimane pool Outer belt

Intermediate belt

▼ ▼ ▼ ▼ ▼▼ ▼ ●● ● ●●● ● ◆ ◆ ◆ ◆◆ ◆ ● ● ● ● ✚ ✚ ◆ ◆

Intermediate belt

Outer belt

▼ ▼▼ ● ● ● ● ◆ ◆ ◆ ◆ ◆◆ ● ● ● ● ● ● ● ● ● ✚ ✚ ✚ ✚ ✚ ✚ ✚ ✚ ✚ ✚ ✚ ◆ ◆◆◆ ◆ ◆ ▼ ▼ ▼ ▼▼ ▼▼▼▼▼ ▼ ▼ ▼▼ ▼▼▼▼▼ ▼ ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ◆ ▼

● ◆ ● ✚ ◆

▼ Plantago coronopus ● Hypericum tomemtosum ◆ Pulicaria arabica

42

Central belt

●

● Isoetes velata ◆ Lythrum biflorum ✚ Scirpus maritimus

▼ Glyceria fluitans ● Myriophyllum alterniflorum ◆ Callitriche brutia

3. Ecosystem and population functioning and dynamics

Each zone is colonised predominantly by species showing specific ecological characteristics: those in the central zone must be able to tolerate a long period of immersion, and those in the outer zone must withstand severe drying out. In the intermediate zone, the stresses caused by flooding and drought are not very intense but interspecific competition is often more intense. The belds of vegetation corresponding to the zones are generally characterised by decreasing species richness from the outer belt towards the centre of the pool (Fig. 11).

■ Seeds stocks ■ Vegetation 40

Number of species

35 30 25 20

This zonation is more or less marked at different sites, depending on the topographical gradients. It rarely conforms to a rigid pattern and varies in relation not only to the topographic and hydrological characteristics of the site but also to unpredictable perturbations (Fig. 12). In addition, the zonation is locally modified by the colonial nature of certain species (mats of perennial rushes for example).

15 10 5 0 Central

Intermediate

Outer

The limits of the zones and their species composition vary between years. They may be displaced towards the centre or the edge of the pool depending on whether the year is very dry or very wet. The relative abundance of perennials and annuals in the belts also varies in accordance with flooding levels: a succession of dry

Figure 11. Species richness of the vegetation and seed stocks in

the three vegetation belts of a daya in Morocco

Map: A. Catard (CEEP), M. Pichaud, A Sandoz & N. Yavercovski (Station biologique de la Tour du Valat)

Figure 12. Zonation of the vegetation in the Rodié pool (Var, France)

Vegetation Meso-hygrophilous grassland (terrestrial grasses dominant) Wet grassland Hygrophytic community with perennial rushes (Juncus conglomeratus) Amphibious community with Ranunculus rodiei Aquatic community with Callitriche (Callitriche brutia) Shrubby vegetation Perennial grassland

0

1.5

3m

43

Mediterranean temporary pools

years will see a steady increase in terrestrial species and perennials, especially in the outer belt of vegetation (Box 15). The interannual variations in the vegetation depend to a large extent on the seedbank. These temporal variations can be revealed by comparing the surface vegetation with the seedbank323. The difference in the relative abundance of species between the seedbank and the vegetation may be caused by a number of factors including the biological characteristics of the species (life history traits*), the processes involved in the accumulation of the seedbank (see below), and the ecological functioning of the pools. Investment in seed production is greater among species with a brief life cycle (annuals) than among those with a long cycle. The size and vigour of the seedlings are directly dependent on the size of the seeds. Depending on the species, the resources allocated to reproduction will be invested either in few, large seeds or in small but very abundant seeds. Thus in the temporary marshes of the Coto Doñana there is a negative exponential relationship between the density of seeds and their individual weight174. Environmental conditions, such as hydrology or competition, may suppress the germination of seeds for variable lengths of time.

Box 15. Interannual changes in the species composition of

the outer zone of the Benslimane pool The species composition of the vegetation was monitored in a Moroccan daya over 7 years (1997-2003). The vegetation changed with rainfall amounts, more rapidly in the outer belt than in the centre of the pool. Between two exceptionally wet years (1997 and 2003) terrestrial perennials (mainly scrub: Cistus salviifolius and C. monspeliensis) recolonised the outer vegetation beld (Fig. 13). They amounted to 27% of the flora in 1997 following exceptional flooding, 73% in 2000 and 2002 during the dry years and fell again to 28% in 2003 after another very wet winter. Rhazi L. based on Rhazi et al.

326

and unpublished data

Figure 13. Percentage of cover of perennials in the outer zone of the Benslimane pool between 1997 and 2003 in relation to cumulated rainfall (number on the bars)

80

300

Cover of perennials (%)

70 60

262

296

323

50 40 30

689

371

668

20 10

The variability of the environmental conditions favour annual species with short cycles, adapted to one or the other phase of the habitat (dry or wet), or to the transition period (amphibious species). Annuals account for about 80% of the characteristic species of temporary wetlands260 (Box 16). Annuals invest a large proportion of their resources in the production of seeds and spores (sexual reproduction), allowing them to withstand the unfavourable period. In addition, they show a certain degree of flexibility in the completion of their biological cycle. Their flowering may be advanced or delayed depending on whether rainfall comes early or late25. Despite the dominance of annuals, perennials can also live in temporary pools if they are able to find their preferred habitat. Among these, Isoetes species (second volume) possess adaptations which give them great flexibility in responding to the irregularity of the alternating dry and wet phases. These are of a physiological nature, such as the ability to carry out photosynthesis in both dry and wet conditions, or the high degree of tolerance of their corms to desiccation. The life cycle may also be shortened as, for example, in Isoetes velata, which, in the extreme conditions of the cupular pools of the Colle du Rouet (Var, France), undergoes an annual cycle303. These populations are only viable because the species is able to produce spores from its first year of life; such species are known as facultative annuals. Perennial plants that are less specialised and more tolerant of both aquatic and terrestrial phases are also found in the pools. They may correspond to amphibious species in conditions of protracted flooding (Scirpus maritimus, Eleocharis palustris) when

Box 16. The hydrological regime and the composition of

the vegetation The date of flooding results from a combination of several variables such as temperature, insolation and day length. In field experiments Grillas & Battedou172 showed that the date of flooding is a decisive factor for the development of communities of aquatic annuals and that it determines their species composition (Fig. 14). Early flooding (in September) leads to the establishment of species-rich communities. Conversely, late flooding (in March) results in a reduction in the number of species and in dominance by opportunist species (Zannichellia spp.). In testing the effects of three flooding dates (February, March and April) on Californian vernal pools, Bliss & Zedler37 recorded a decrease of 52% in species richness for late flooding, in April, compared with early flooding, in February. With early flooding the vegetation is rich in the characteristic species of temporary pools. In contrast, during late flooding the vegetation becomes more commonplace through an increase in more generalist species (Lythrum hyssopifolium, Crassula aquatica, etc.). These authors considered that the suite of characteristic temporary-pool species would be protected from “out-of-season” germination by an inhibitory mechanism linked to temperature increases. Gauthier P. & P. Grillas

0 1997

44

Survival strategies associated with hydrological fluctuations

1998

1999

2000

2001

2002

2003

3. Ecosystem and population functioning and dynamics

Box 17. Key factors for the development of Charophytes* In temporary pools, the Characeae are regulated by the dynamics of the flooding/drying phases. Their vegetative structures cannot tolerate any drying out and in dry conditions they can only survive in the form of perennating organs (oospores* and gyrogonites*). Their biological cycle, from germination to the production of perennating organs, generally lasts from five to seven months. A period of three months under water is the absolute minimum required for their development, even among early species. The oospores do not break dormancy* until 21-28 days after flooding400, and if the period of submersion is too short, the plants will not be able to develop to the sexual reproductive stage. The duration of development is crucial and excludes these plants from ephemeral habitats which are only flooded for a few weeks. The date of flooding, and its correlate, temperature, have a strong influence on the type of species which are able to germinate. Only autumn or early winter flooding allows the development of the vernal species which are of the highest value in terms of natural heritage, such as for example Nitella opaca, Tolypella spp., Sphaerochara and Chara imperfecta. These species are all the more valuable as life forms in the pools since they appear at a time of year when aquatic phanerogams are still completely absent. These taxa develop at low temperatures (less than 10°C) and yellow and decompose above 18.5°C (361). Their rarity is probably due to the fact that good conditions do not occur every year. At the LIFE sites in the Var Département, the 2000/01 cycle was optimal for these plants, whereas they did not reappear during the two following winters. Delayed flooding resulted in strong competition with higher plants and gave rise to an increase in opportunistic species such as Chara vulgaris and C. globularis. This impoverished and generalist* flora occurs in 80% of surveyed pools in Languedoc-Roussillon (Soulié-Märsche, pers. obs.).

gyrogonites which can then withstand drought conditions lasting for several consecutive years. The surface area and topography of a site influence the diversity of Characeae. Particularly light-demanding species will in general only grow at depths of under 2 m. An environment where depth increases progressively (0-2 or even 4 m) will give rise to a gradient of Characeae species according to depth, as well as to a seasonal succession as the depth decreases due to evaporation. The Bonne Cougne pool (Var) has an exceptional degree of biodiversity thanks to its wide range of constituent microhabitats130. Ten species of Charophytes, of which five are extremely rare, appeared in turn here during the 2000/01 cycle361. The Protection of Characeae, and especially rare species, at temporary pools requires above all the continuation of alternating periods of flooding and drying out. A temporary pool transformed into a permanent habitat will undergo rapid changes in its range of species and will be occupied by commonplace species, such as Chara vulgaris which is by far the most widespread in Europe. Many Characeae are also capable of vegetative reproduction* by nodal bulbils, and adopt a strategy of spreading when they occur in a permanent habitat, which results in monospecific stands of lesser interest for biodiversity. A second threat factor, not only for rare species but also for Characeae in general, is pollution in the broad sense and overenrichment with nutrients*. The Characeae can only tolerate low levels of sulphates, nitrates and phosphates in the water. In pools surrounded by arable land in Languedoc-Roussillon, the leaching of fertilisers and herbicides must be regarded as the reason for the disappearance of many populations over the course of recent decades. Soulié-Märsche I.

Light penetration and temperature are the key factors essential for the production of seeds and the formation of oospores and gyrogonites, which are especially necessary in a temporary environment. Temporary-pool species invest heavily in the formation of

Figure 14. Species composition of the vegetation in relation to the date of flooding (based on Grillas171)

September 24

November 26

■ Zannichellia pedunculata

■ Chara aspera

■ Zannichellia obtusifolia

■ Chara sp.

March 11

■ Ranunculus sp. ■ Tolypella sp.

■ Callitriche sp.

45

Mediterranean temporary pools

small seeds, with mechanisms to delay germination, has been selected to facilitate the development of this seedbank (see Chapter 3f.)

Roché J.

Among aquatic annuals, the ability to produce seeds rapidly and in large numbers is vital for replenishing the bank of seeds or spores. Callitriche truncata germinates, grows and reproduces in under 30 days, Ranunculus peltatus requires more time to reproduce but can complete its reproductive cycle after the environment has dried out thanks to its amphibious growth forms407. The Characeae require long periods of immersion to reproduce (Box 17). They do not complete their reproductive cycle every year but compensate for this with a massive production of oospores during favourable years, associated with a low annual germination rate (maintenance of the stock).

Annual and amphibious, Ranunculus baudotii completes its reproductive cycle in the dry phase

incomplete drying out permits the survival of rhizomes and corms. Opportunist terrestrial perennial species also temporarily colonise temporary pools during dry years, in the dried-out zones. These include for example grasses such as Dactylis hispanica, Holcus lanatus or Agropyrum campestre in Les Maures. Woody plants present in the adjoining ecosystems are also found here, such as Cistus. These species undergo drastic fluctuations in abundance: they thrive during a series of dry years and are wiped out when flooding takes place. Finally, some terrestrial species are well able to tolerate winter flooding and are frequently found in temporary pools although they are not specific to this habitat (for example Dittrichia viscosa and Cynodon dactylon).

The seedbank As well as the organs of vegetative propagation of perennial plants (bulbs, bulbils, rhizomes, turions, dormant buds, etc.), the sediment contains the seeds or oospores* resulting from the sexual reproduction. By producing large offspring, vegetative reproductive organs confer a competitive advantage (production) compared with seeds in their early stages of development. These organs are much less common in temporary habitats because of their lower resistance to drying out. The life expectancy of seeds is very variable from one plant species to another. Those which survive for less than one year (transitory stocks) do not accumulate over time and their numbers present in the seedbank fluctuate very rapidly. Other species have long-lived seeds which tend to build up, in great numbers, in the sediment. Under the very variable environmental conditions in temporary pools, species and populations of plants have evolved towards the production of seeds forming stocks which persist in the soil for more than one season. This long-lived seedbank is of vital importance when the populations are subject to frequent reproductive failure or when environmental conditions are unfavourable for germination. Various strategies, including the production of a large number of long-lived, weakly dispersing

46

The number of seeds produced by each species is correlated with its biomass41, 174. Also, the biomass accumulated by aquatic annual plants is itself correlated with the length of the growing season, determined by the dates of flooding and drying out172. There are few specialised dispersal mechanisms among the plants of temporary pools: it is as if there is less danger in remaining where the preceding generation has succeeded in reproducing than in risking a dispersal which is very unpredictable in a rare and discontinuous environment. Klinkhamer et al.209 has shown that the more likely species are to accumulate in a seedbank, the less well adapted they are to dispersal.

Box 18. Longevity of the seedbank Seedbanks increase the resilience of the vegetation of temporary pools, i.e. their capacity to rebuild themselves following a perturbation60. Several studies of temporary pools have demonstrated the sporadic appearance (every three, five or ten years), sometimes in large numbers, of species such as Elatine brochonii or Damasonium stellatum, for example326. This depends on the dormancy* and longevity of the seeds. Longevity is very variable between species: sporocarps of Marsilea strigosa remained viable after being kept in a herbarium for a hundred years84, whereas those of Isoetes setacea had lost their viability after about ten years in similar storage conditions (Michaux-Ferrière, pers. com.). In addition, it is probable that storage conditions affect this longevity and that it will be shorter in nature than in a herbarium. In Australia, the viability of seedbanks of 21 species from six different pools was assessed: after 11 years only one sample still gave rise to germinations and only two species (Juncus articulatus and Myriophillum variifolium) continued to germinate61. The life expectancy of the seeds of most species from Australian pools is at least 3 or 4 years, but the average or maximum duration remains unknown60. In the course of projects to restore two temporary pools in southern France (Péguière in the Var and Grammont in the Hérault), preliminary analysis of seed stocks showed that the characteristic species were no longer present (or were no longer viable) after about 15 years (Grillas, unpublished) and 30 years173 respectively. Gauthier P. & P. Grillas

3. Ecosystem and population functioning and dynamics

Box 19. Key factors in the functioning and dynamics of bryophyte* populations The most specialised suites of bryophytes are closely linked with the alternating wet period/dry period regime. Most bryophyte species of temporary pools are more or less temporary pioneers* with specialised strategies. The fugitive annual speciesa, annual shuttle speciesb as well as colonistsc are largely predominant here. They are often ephemeral species (sometimes living only for a few weeks), generally producing spores in large quantities. These spores allow them to survive in a dormant form during the dry period. These species may also possess vegetative perennating organs. This is the case among many Bryaceae which produce one or several types of propagules* (tuberiform* propagules on the rhizoids*, gemmiform * propagules in the leaf axils, etc.) and among some liverworts such as Phaeoceros bulbiculosus which have stalked bulbils on the underside of the thallus. The perennial species, truly stress-tolerant, are much rarer and strictly confined to the outer zones of temporary pools where the shade from taller plants is greater and the soil a little deeper. The usual morphological characters of xerophytic (drought-tolerant) species, such as the presence of scales, papillae or hairs, are not sufficient to explain the impressive resistance of the bryophytes, particularly liverworts, to the severe conditions of the dry season. Additional complex mechanisms, of a physiological nature, are involved. Anabiosis (ability to regenerate living tissue by rehydration of tissue which has been subjected to extreme desiccation) among a considerable number of bryophytes is probably the essential factor. Some species considered to be annuals can in fact exhibit mechanisms of this type in certain conditions. The thalloid liverworts and in particular the genus Riccia, as well as the Pottiaceae, have many reviving species.

Among temporary-pool species, dormancy* mechanisms limit the percentage of germination in a given year41, reducing the risk of population extinctions365. The breaking of dormancy is partly controlled by environmental factors such as light, the degree of water saturation of the sediment, and temperature, but also by physiological processes. In Elatine brochonii, Rhazi et al.324 have demonstrated two factors controlling germination: water saturation of the sediment and light. Few data exist regarding the percentage germination rates of seeds from one generation over the course of a single hydrological cycle or flooding event. In Australia, Brock62 recorded very low germination rates (2.5%) during the first year after re-filling with water while Bonis et al.42 reported much higher germination rates, varying between 30% for Charophytes and 50% for Zannichellia. Further, these authors noted that species capable of rapid germination (non-dormant) as soon as the seeds are produced will enter into dormancy if they do not quickly experience conditions favourable for their germination. Some species (for example Callitriche truncata) may possess, at the same time, a stock of young

Owing to the drastic environmental constraints, bryophyte populations are very unstable in time and space and are subject to wide variations in numbers from one year to another. The importance of the bryophyte layer in the equilibrium of the “temporary pool” habitat is often underestimated. Mats of Potiaceae, such as those of Pleurochaete squarrosa, a competitive perennial species frequently found around the edges of pools, or the compact crusts formed by many thalloid liverworts, impede severe drying-out of the substrate during critical periods and so to some extent favour Isoetion groupings. Other competitive perennial bryophytes may, on the other hand, promote evaporation in the wettest basins by bringing a greater surface area of water into contact with the surrounding air (capillary action). Due to the significant amount of accumulated biomass which it constitutes, the bryophyte layer plays a considerable role in the organic enrichment of the quasi-skeletal soils of many temporary pools. During the unfavourable season, liverwort crusts may also play a role in the protection of the sediment and its associated micro-organisms from external stresses (radiation, wind, erosion etc.). Hugonnot V. & J.P. Hébrard

a. Fugitive annual species are ephemeral species with heavy investment in sexual reproduction (many sporophytes), no asexual reproduction, and small long-lived spores. b. Annual shuttle species are short-lived (but sometimes more than one year), with heavy investment in sexual reproduction (many sporophytes), no asexual reproduction, and large spores (hence poor dispersal) with medium longevity. c. Colonists are short-lived species with heavy investment in both sexual and asexual reproduction and small long-lived spores.

seeds with high rates of germination and an older stock which germinate gradually. Information regarding the longevity of seeds is scarce and sometimes contradictory (Box 18). At a given site, differences may often be seen between the seedbank and the surface vegetation. The presence in the seedbank of species absent from the vegetation may indicate that the environmental conditions are not allowing these species to break dormancy, that germination is being followed by failure, or that some species are being eliminated by competition with the communities that are already established. On the other hand, the presence in the vegetation of species absent from the seedbank may reflect a transitory seedbank, recent colonisation (opportunistic), or solely vegetative reproduction* by some species. The number of viable seeds in the bank, rather than counts of the number of shoots germinating in a given year (eminently variable from one year to another) is the best method for estimating population size.

47

Mediterranean temporary pools

d. Amphibians

Box 20. Plasticity of reproduction of species in relation to

dates of submersion Jakob C. & M. Cheylan

In the face of the climatic vagaries of the Mediterranean region, different species have differing capacities to adapt. Some are flexible, in general those of Mediterranean origins such as the Western Spadefoot, Parsley Frog and Painted Frog, while some are rigid, in general species of mid-European origins such as the Common Toad and the Agile Frog333. The first group are able to initiate egg laying several times per year, in response to heavy rain; the second group only lay once per year, in general at the end of winter (February-March). Each species therefore has a different reproductive phenology. Between-year variation in the date of flooding allows every species to breed in one year out of two, on average, at a given site. Such a biannual or multi-year cycle is well known for amphibians around the Mediterranean117, 181.

Nature of the habitat, physical and biotic factors Mediterranean temporary pools are very attractive habitats for most amphibian species due to several key factors: absence of predators (notably fish), absence of currents or sudden changes in the water level, and high spring temperatures resulting from their shallow depth. The key factors in the breeding habitat of amphibians have been the subject of many studies in the Mediterranean region (see for example Pavignano292). The duration of flooding is a particularly important factor as it determines the time available for larval development, which itself influences breeding success109, 194. Species such as the Marbled Newt, the Iberian Green Frog and the Western Spadefoot require a long period of flooding to complete their larval cycle (2 to 4 months). In contrast, the larval development of the Natterjack Toad or the Painted Frog is extremely rapid (minimum 30 days, see also Box 20). The depth of the pool strongly influences the length of the flooded period198. It often provides an indication of the potential for the presence of a given species, but this is not always the

Jakob C.

Cheylan M.

case for example in karst pools where fluctuations in water level can be very rapid. The date of flooding also plays an important role for the range and number of species present at a site. Early flooding favours species which breed early (Common Toad, Agile Frog, Parsley Frog, etc.) but does not affect late species (Stripeless Tree Frog, Green Frog). In addition, some species take advantage of autumn flooding to breed (mainly Western Spadefoot, Parsley Frog and Painted Frog) while others do not (Common Toad, Agile Frog, Stripeless Tree Frog, newts, etc.). The presence of aquatic vegetation will de decisive for some species292 such as newts and the Stripeless Tree Frog, in particular for attaching their eggs113. On the other hand, it will be of little importance for others (Parsley Frogs, Western Spadefoots, Painted Frogs) and even unfavourable for species such as the Natterjack Toad which prefers poorly vegetated pools. Fringing vegetation will be preferred by species such as Common Tree Frog, the Common Toad, Agile Frog and newts, immaterial to Painted Frogs and Parsley Frogs, and rather unfavourable to the Western Spadefoot or the Natterjack Toad. Shading of the pools is a favourable factor for species such as newts116, 350 but unfavourable for others such as the Natterjack Toad which prefers sunlit pools with a higher water temperature28. However, the Marbled Newt breeds also in slightly shaded pools, provided the depth of the pool allows a favourable water temperature. Nil or very low salinity is required by most amphibians. Hardly any species apart from the Western Spadefoot, Painted Frog and Natterjack Toad will tolerate slightly saline water. Almost all species, except for the Common Toad and Green Frogs, are sensitive to the presence of predators, especially fish predators of eggs and tadpoles, which are generally absent from endorheic* temporary pools (Scoccianti355 for review).

Triturus marmoratus rolls up its eggs in the leaves of submerged plants

48

Due to the close interdependence of these various factors it is difficult to determine their relative importance. In addition it is desirable to take other factors into account, such as the history of the pool, its substrate, its geographic position and its landscape context (degree of isolation in relation to other pools).

3. Ecosystem and population functioning and dynamics

Instability of the physical environment and the requirements of the species for their annual cycles The hydroperiod* is of great importance for the reproduction and survival of species over time. It largely determines breeding success and, hence, which species are present at a given site. Among Mediterranean batrachian communities, species are more or less adaptable as regards the date and duration of flooding (see Box 20). Some species use the pools as soon as they fill with water, in autumn, for feeding (Marbled Newt, Great Crested Newt) or for breeding (Western Spadefoot); others only at the end of winter (Common Toad, Agile Frog) and, lastly, others at the end of spring (Stripeless Tree Frog, Green Frogs). To these three categories may be added the opportunist species such as the Parsley Frog and the Painted Frog, which breed as soon as it rains, except in the middle of winter or the middle of summer. The wide inter-year variability in the date of flooding of Mediterranean endorheic pools may result in an absence of breeding in a given year for autumn or late-winter species (Box 21 and Tab. 1 Chapter 2a). Breeding success may therefore vary between years, a markedly different situation from that observed outside the Mediterranean region where amphibian breeding is, more often than not, annual. In general, this does not place the long-term

Box 21. Variability in rainfall (1997-2000) and breeding

among amphibians in the pools of Roque-Haute (Hérault, France) In 1999, belated flooding of the 198 pools at the Roque-Haute Nature Reserve (in May instead of October-November) resulted in practically a reversed situation among the amphibian community compared with other years198. That year, the species which colonised most pools in 1997, 1998 and 2000 were unable to breed. Conversely, the species which usually occupied a small number of pools were able to breed more widely (Tab. 12). Early species such as the Marbled Newt and the Palmate Newt, as well as the late species, Green Frog, were unable to match their laying date to the delayed flooding date. On the other hand flexible species such as the Natterjack Toad bred much more successfully that year.

Box 22. Duration and et flexibility of larval development In the Mediterranean region, the duration of larval development strongly influences breeding success. The larval cycles of species found here may be long (newts, Western Spadefoot, Midwife Toads), short (Natterjack Toad, Painted Frogs) or intermediate (Parsley Frog, Stripeless Tree Frog, Green Frogs). Since the time for which the pool is filled depends on rainfall, the drying-out of the breeding site may take place earlier in a year of low rainfall, which will cause breeding failure among species with long cycles or late breeding. In response to these hazards, amphibians are able, to a certain extent (each species having its own characteristic degree of response), to adjust the length of their larval development period to the duration of flooding110. In favourable years large young will be produced, and in unfavourable years smaller young. The lowering of the water level also has the effect of raising the water temperature, which allows larvae to accelerate their development. All these mechanisms combine to ensure that amphibians are well adapted to the unpredictable character of the Mediterranean climate. Jakob C.

survival of the population in any danger due to the long-lived nature of most of the species. The duration of the flooding period may also vary between years, with a considerable effect on the breeding success of the species (Box 22). A species that is well-adapted to Mediterranean pools will be able to complete or accelerate its development up to metamorphosis to avoid early drying out, whereas a species with a long larval cycle will not be able to lay eggs or will be doomed to fail in its breeding that year. Finally, occasional flooding is of great importance for weakly competitive species, such as the Natterjack Toad, which particularly seeks out pools that are depauperate in invertebrate predators and in other amphibian species.

Jakob C.

Table 12. Number of pools containing newt larvae and tadpoles between 1997 and 2000 at the Roque-Haute Nature Reserve site.

English name

1997

1998

Bufo calamita

1999

2000

Natterjack Toad

2

0

24

2

Hyla meridionalis

Stripeless Tree Frog

42

29

39

35

Pelobates cultripes

Western Spadefoot

16

1

4

0

Pelodytes punctatus

Parsley Frog

23

17

10

0

Rana perezi

Iberian Green Frog

9

10

0

1

Triturus helveticus

Palmate Newt

40

39

0

27

Triturus marmoratus

Marbled Newt

37

33

0

34

Cheylan M.

Year Scientific name

A dried-out clutch of Pelodytes punctatus eggs in a prematurely dried-up pool

49

Mediterranean temporary pools

e. Invertebrates

Spatial and temporal segregation The pools form small, self-contained habitats which give rise without doubt to manifestations of competition273. This competition is partly reduced by two mechanisms: temporal segregation and spatial segregation. Temporal segregation is strongly marked for breeding dates (presence of adults), less marked as regards larvae. A study carried out in Spain showed that there is a significant difference between the breeding period of different species but also within single species333, larger and more competitive males being the first to occupy the pool in order to mate. In southern France it is rare to observe more than two or three species of Anura breeding simultaneously at one site, contacts between species thus being limited. The combinations most often observed involve the Western Spadefoot and the Parsley Frog in autumn, the Common Toad, the Western Spadefoot and the Parsley Frog at the end of winter, or the Western Spadefoot and the Natterjack Toad in spring. Sometimes this overlap results in interspecific matings, for example between a male Common Toad and a female Western Spadefoot, but these cases are uncommon. Spatial segregation reinforces the isolation of the breeding adults, particularly in the case of a network of pools (Box 23). In the case of single pools used by several species (up to six species of Anura in southern France), spatial segregation is usually observed during egg laying. At the Fertalières pool (Hérault), laying by Western Spadefoots and Common Toads is always located at the same sections of bank from one year to another, with fairly well-marked separation of the two species. In the same way, tadpoles of Natterjack Toads, Parsley Frogs and Western Spadefoots will not use exactly the same vegetation zones within a pool: the first two species will be confined to the pool margin, in shallower areas, and the third to the middle of the pool, in the deepest parts.

Box 23. Spatial and temporal segregation in pools at

Doñana Diaz-Paniagua114, 115, 116 was able to observe the larval periods of 10 species of amphibians over six years in a network of 16 temporary pools in the Doñana National Park (southwest Spain). The species which laid eggs earliest in the season, i.e. in autumn, were Discoglossus galganoi and Pelobates cultripes. Over the course of the study, these two species showed the widest variation in the date on which laying began, depending on annual variations in the flooding of the pools. The spatial segregation of the species depended mainly on the depth of the pool. Three groups were identified: a group which breeds in the most ephemeral pools, thereby avoiding the other species (Bufo calamita and Discoglossus galganoi), a group breeding in temporary pools which remain flooded for a fairly long time (Triturus marmoratus, T. boscai and Hyla meridionalis), and a group using pools which are flooded for a long time, even permanently (Pelodytes punctatus, Pelobates cultripes, Bufo bufo, Rana perezi and Pleurodeles waltl). Jakob C.

50

Thiéry A. Many studies have been concerned with the richness of macrocrustacean communities in temporary habitats, in several countries subject to various different climatic influences, in Europe9, 52, 282, 410, Australia26, 218, the USA168 and Africa49, 106, 147, 148, 189, 250. On the other hand few studies have been carried out into their functional aspects. Hydrology nevertheless appears as one of the key factors: it determines the presence, composition and structure of the biocenoses (flora, fauna etc.), and regulates the aquatic invertebrate communities.

Habitat structure Three principal hydrological parameters may be distinguished: the duration of flooding, water quality and the time (season) at which flooding takes place. The duration of flooding is determined by climate (amounts of rainfall, etc.), soil (type, permeability etc.), the depth of the pool, and the presence of and distance from groundwater. It is directly involved in community structuring as a result of the residentmigrant duality among the fauna, as defined by Giudicelli & Thiéry166 (Chapter 2d). According to data collected at temporary pools from a range of Mediterranean Basin countries (France, Morocco, Algeria, etc.), colonisation develops375, 377, 380 in accordance with four more or less distinct phases: A. A pioneer stage with low species richness, dominance of resident species with dormant stages and a few migrant species (fewer than five), B. A stage of increasing richness through arrivals of migrant species (Heteroptera, Coleoptera, Diptera, etc.), C. An equilibrium stage (progression of life cycles, reproduction etc.), D. A phase of senescence, where emigration and the disappearance of some resident species with short cycles (Anostraca, Cladocera, Rotifera, etc.) may be observed. Based on this model, the duration of flooding will determine whether or not these successive phases can develop. This dynamic model is still theoretical and needs to be tailored according to the range of different situations: • In the case of ephemeral habitats (flooded for less than three weeks, Fig. 15a), the faunistic richness is poor. The invertebrate fauna is represented only by some crustaceans with short cycles (cyclopoid copepods) a few worms, and generalist* Diptera (Chironomidae, Culicidae etc.) which come to lay eggs as soon as they detect any water. Some Coleoptera, such as Agabus nebulosus, may rapidly colonise the new habitat and prey heavily upon the young microfauna206. In these habitats the species diversity is low, due to the proliferation of a few species (vacant ecological niches, nutritional resources in excess). • In temporary pools (flooded for one to three months, Fig. 15b): the pioneer species are present, including in particular some anostracan macrocrustaceans (Branchipus, Lindiriella, etc.) which are able to reproduce here owing to the longer period of flooding. This is followed by the second phase with the arrival of migratory insects. This period is characterised by a richness which increases with time. Diversity increases due to the numerical re-balancing of the different species following the establishment of trophic*

3. Ecosystem and population functioning and dynamics

a) 7

1 2 3 4 5 6 7

5 4 3 6

- Oligochaete annelid - Nematode - Anostracan - Cladoceran - Cyclopoid (female with eggs) - Chironomid larva - Coleopteran (Agabus nebulosus) Migrants Resting eggs

1 2

11

18

10

14

13

12

15 17

19 8

16

20

9 7

b) 1 - Annelid 2 - Ostracod 3 - Caenis larva (Ephemera) 4 - Anisopteran larva (Odonata) 5 - Corixid 6 - Notostracan (Triops) 7 - Aquatic mite 8 - Trichopteran larva 9 - Chironomid larva 10 - Notonectid (Heteroptera)

6 4

5 1

11 - Gyrinus (Coleoptera) 12 - Gerris (Heteroptera) 13 - Anostracan 14 - Hydrophilid

2 15 16 17 18

3 19 - Calanoid 20 - Harpacticoid Migrants Resting eggs

- Dytiscid Coleopteran - Coleopteran larva - Clœon larva (Ephemera) - Cladoceran

Figure 15. Structure of invertebrate populations in temporary pools in relation to the duration of flooding, a) ephemeral pool, b) temporary pool

Figure 16. Succession of populations of cladocerans Daphnia, Simo-

relationships (food chains). The optimum point attained by the curve depends on the date of drying out. • In pools with a longer duration of flooding (three to eight months) richness continues to increase and all four phases may be observed (e.g. at Bonne Cougne). Over 100 species may sometimes be noted in the biotope, albeit with time-lags due to varying dates of arrival and different lifespans. Over the course of time, a succession of populations may be observed211, 218, 363, 375, 377, 380, 410 (Fig. 16). Within the biotope segregation is also spatial, due to the varying ecological requirements of the different species

Numbers.L-1

cephalus and Chrydorida illustrating the trophic* non-competition within a single pool (based on Laugier227) 14 12 10 8 6 4 2 0

Chydoridae Simocephalus Daphnia

0

1,5

3,5

5,1

6,8

8,8

10,5

12

Time (days)

51

Mediterranean temporary pools

(planktonic, benthic etc.). In a temporary pool, competing species are rare owing to the diversity of microhabitats and of feeding methods (carnivores, filter feeders, grazers, detritivores, etc.). This low level of competition results both from the time lag affecting different growth stages and from habitat preferences (Fig. 16). For example, if two anostracans coexist at a time t, one will be at the breeding adult stage (Branchipus schaefferi or Tanymastix stagnalis) while the second will be at the juvenile stage (slowgrowing Chirocephalus diaphanus). These two species exploit different food resources382 according to their anatomical differences (distances between the bristles on their foliaceous appendages*).

Geographical factors Light conditions (pools in open country v. pools surrounded by woodland, etc.) and accessibility for migratory insects and birds (see Box 29, Chapter 3f) play an important role in species composition and diversity. Interchanges of fauna (connectivity*) depends also on the distance between the pool and other aquatic biotopes, temporary or permanent10 (network of canals, rivers, lakes, ponds etc.). Temporary pools function rather like islands125, 380 with, in particular, species richness linked with the surface area of the pool (Fig. 17). As with island habitats, the processes of speciation are observed with greater frequency than for continuous habitats, with the appearance of endemic* species27 such as Linderiella, Tanymastigites, Tanymastix, Branchipus, etc.

Water quality Physiological requirements of the aquatic invertebrate fauna (excretion and respiration) partly determine their potential presence in a pool. Osmotic regulation is dependent on the mineral content of the pool (salinity, hardness, etc.), which varies between sites but also over the course of an annual cycle. Most freshwater* invertebrates do not survive in water with a conductivity greater than 1.5-2 mS.cm-1. Osmotic processes also influence the hatching of the resting eggs of branchiopod and copepod crustaceans. Hence any pollution (nitrates, phosphates, chlorides, etc.) endangers the survival of these species. Temperature and dissolved oxygen content are limiting factors for survival (see Boxes 24 and 25). Figure 17. Evolution in the number of invertebrate species in rela-

tion to the diameter of the pool (based on Giudicelli & Thiéry166) 100 Total invertebrates richness

90 80

Because temporary pools are shallow and have only sparse plant cover, conditions within them may on occasion be incompatible with aquatic life. Temperature acts directly on the physiology of invertebrate organisms (poikilotherms*) but also indirectly through its effects on the solubility of oxygen. During warm periods, when the water temperature in the pools may exceed 30°C in the daytime, the crustaceans Triops, for example, are close to their lethal limit, corresponding to the temperature threshold for the precipitation of protein. Sudden disappearances of whole populations may occur in a few hours when the water temperature exceeds the threshold of 32-33°C (Thiéry, original data). If the rate of development accelerates and fecundity increases, this is compensated for by a reduced size of individuals at maturity and by reduced longevity380. The temporary pools of arid areas are particularly characterised by the turbidity of their water. In turbid temporary pools in Israel414, New Zealand26 and the USA132, the existence of microstratification, with a decrease in temperature of 8 to 10°C at a depth of 20 cm (± 2 cm), had long remained unexplained. Thiéry380 has accounted for this stratification in the dayas of western Morocco. In summary, particulate organic material adsorbed onto suspended clay traps solar radiation and, depending on pH, remains in suspension due to increased viscosity of the upper layer of water (epilimnion). The 20-cm deep water layer which has absorbed heat during the daylight remains at the surface during the night, without mixing with the deeper layer. This deeper layer therefore maintains its night-time temperature, i.e. 8 to 10°C lower than the surface. This deep zone (hypolimnion) provides a thermal refuge for crustaceans, which congregate there during the daytime. As drying out steadily proceeds, this microthermocline disappears and the water column becomes thermally homogenous. In response to the marked increase in temperature, crustaceans will produce thermo-protective proteins, “Heat Shock Proteins” (HSPs) which allow them to survive for a few hours at more than 36°C (1 hr at 40°C for Artemia). This corresponds to a metabolic response to heat stress as shown by the studies of Artemia by Miller & McLennan266 and of Lepidurus by Jean et al.202. Increasing water temperature also plays a role in the activity of insects, by triggering waves of flight and migration among the Corixidae for example (Sigara, etc.). Conversely, warm water at 20 to 25°C will be sought out by insects at the limit of their biogeographical range, for example the case of species of “Ethiopian” origin such as the anisopteran odonate Crocothemis erythraea122, 123, the heteropteran Anisops sardea, and the coleopteran Eretes sticticus, wrongly considered to be endemic to Provence. Thiéry A

70 60 50 40 30 20 10 0 0

20

40

Diameter of the pool (m)

52

Box 24. Temporary pools: overheated habitats?

60

80

3. Ecosystem and population functioning and dynamics

Macrophytes The final factor of importance for the invertebrate macrofauna is the presence of submerged macrophytes. These act as microhabitat refugia, dividing up the water column and creating a more heterogeneous habitat which favours increased biodiversity399. As observed by Aguesse2, rice fields are suitable for Ischnura elegans, I. pumilio, Crocothemis erythraea and Sympetrum fonscolombei. In general, the diversity of the vegetation and of the hydrophytes* is a decisive factor influencing the odonate richness of a pool120. Emergent plants provide large surfaces colonised by a sessile* microfauna which will be a nutritional resource for grazing invertebrates (Micronecta, Sigara, etc.). For their part, the Characeae play an important role in trapping sediments and helping to

Box 25. Dissolved oxygen and temporary habitats In temporary habitats, the dissolved oxygen content of the water is one of the principal factors limiting the survival of the invertebrate fauna. While most animals are not affected by supersaturation above 150%, subsaturation levels of less than 20%, even for a limited period (sometimes for a few hours during the night), constitute lethal thresholds. In temporary pools, oxygen levels vary in time and in relation to the presence of submerged plants380 (Fig. 18). The submerged vegetation (Ranunculus, filamentous algae Spirogyra, etc.) tends to produce high diurnal levels of O2 in the water (photosynthesis) and low values at night (plant respiration). Aquatic plants with emergent leaves (Eleocharis, Carex, Isoetes, Glyceria, etc.) only have a slight effect. In addition, given the physical laws relating to the solubility of gases, the available oxygen decreases as the water temperature increases. When their habitat becomes oxygen-poor, the aquatic invertebrates respond in various ways: • by stages of life with lower metabolic rates to limit their need for oxygen, • by modifying their biological activities and behaviour (locomotion, etc.), • by synthesising respiratory pigments that are better able to bond with oxygen. This is the case for some crustaceans, insects and molluscs. Branchiopod crustaceans (Triops for example) are capable of synthesising extra-cellular haemoglobin149. In the anostracans Artemia there are three types of haemoglobins, capable of bonding reversibly with oxygen, which give them their red colouration in anoxic conditions107, 268. Pulmonate gastropod molluscs such as Planorbis, as well as the larvae of the chironomid dipterans Chironomus of the plumosus and thumni group, also have this ability413. As well as producing haemoglobins, crustaceans are able to adapt their biological activity by increasing the rate at which

clarify the water70, 342, 404, which has variable effects depending on the crustacean species. Cladocerans, for example, benefit from an increase in water clarity. Characeae also metabolise calcium and carbonates for use in the construction of their vegetative structure and so play a part in variations in water quality (see Box 13, Chapter 2a). While the dynamic phases A and B described above are only slightly vegetated (inhibited germination, slow growth, etc.), macrophytes constitute a decisive factor in the development of animal communities during phases C and D.

Development of temporary pools in the medium and long term Over time, at the decade scale, the temporary pool does not remain stable, but undergoes changes in its morphology (silting up, etc.) which lead to changes in the structure of its biological community.

their swimming appendages beat (forced ventilation through increased volume of water bathing the gills). They modify their behaviour by reducing their consumption of dissolved oxygen134 as well as by vertical migrations among the anostracans271, turning upside-down in the case of Triops (which makes use of the most oxygenated fringe of water at the air/water interface) and accumulation in the deepest and hence coolest part of the pool among notostracans. One study has shown that Triops and Leptesteria have very low lethal thresholds, close to 10% of saturation, levels which are only rarely encountered in the natural environment380. Martin C. & A. Thiéry

Figure 18. Evolution during the course of a day in the oxygen dis-

solved and in the pH in open water and in a vegetation bed (Moroccan pool) (based on Thiéry380) 16 15 14 13 Dissolved oxygen (mg.L-1)

During major algal blooms in the warm season (spring and summer), dissolved oxygen deficits at night may become lethal for crustaceans380.

12 11 10 9 8 7 6 7h ■

9h

Ranunculus

11h ■

13h Isoetes

15h ■

17h

19h

Open water

53

Mediterranean temporary pools

f. Population dynamics and genetics P. Gauthier & P. Grillas

Introduction Temporary pools are discontinuously distributed. In the same way as islands, they are separated by very different habitats. For

species strictly dependent on these pools, the analogy with islands is relevant; populations are isolated, often fluctuating, and with a poor capacity for dispersal. On the other hand, for less specialised species, the pools may constitute secondary, more or less long-lasting habitats. The pools are therefore populated both by species which strictly depend on this habitat and by others which make use of it in an opportunistic way. It is mainly the biology of populations of specialist temporary wetland species which is considered here: those which do not have a refuge or a population source outside temporary pool

Box 26. Monitoring a population: the case of the Great

Crested Newt at the Valliguières site in the Gard (southern France)

Methods used: A Capture-Mark-Recapture (CMR) protocol was initiated in January 2000, based on one visit every 15 days during the period when newts are present at the site (approximately November to May, with wide annual variations in the period of presence). Newts were captured at night with a pond net and individually identified using the black markings on their undersides (individual photo-identification). Thirty-four visits to the site resulted in 645 captures comprising 216 different individuals. Results: The population size was estimated as 199 individuals in 2001 (177-237) and 119 in 2002 (110-133) with a total of 213 individuals over the two years, confirming the hypothesis of a small population (about 100 breeding females). The size distribution confirmed the absence of juveniles in the population in 2001. Estimates of demographic parameters (adult survival rate, recruitment* rate) do not permit precise modelling of the future of the population. A further year of monitoring will be necessary. However, the results already show that, with an adult survival rate estimated to be between 59% and 88% per year, the probability of extinction of the population is very high. It would only be able to maintain itself if the adult survival rate were high (88%/yr) and if at least 56 individuals were recruited every three years approximately, which is a high value but no doubt feasible in practice. In the absence of any intervention in the habitat (maintenance of a two- or even three-yearly flooding cycle) a recruitment of about 30% at each successful breeding will be necessary to maintain the population. With annual breeding, the recruitment rate necessary to stabilise the population is no more than 15%.

Nighttime capture and individual recognition of Triturus cristatus at the Etang de Valliguières

Given the hypothesis of successful breeding every two years, the population has a 95% chance of sustaining itself for longer than 100 years if adult survival is constant at 88% and if, at a minimum, 32 individuals are recruited into the population every two years (Fig. 19). In view of these findings, the LIFE “Temporary Pools” project has identified several management actions which will favour the maintenance and survival of the newt population: digging out the pool to extend the flooded period and to allow the larvae to successfully metamorphose more frequently, the creation of additional pools to boost numbers of newts and to reduce the risks of extinction, management of the vegetation cover to facilitate the movements of the newts during their terrestrial phase and placing piles of stones close to the banks to protect emerging juvenile amphibians from wild boar. Cheylan M., K. Lombardini & A. Besnard Figure 19. Probability of extinction of an isolated Great Crested Newt population subjected to drying out with varying regularity (based on Besnard32) Initial number: 200 individuals Extinction probability at 50 years

Problems: This pool is flooded sporadically and in response to heavy rains which supply the subterranean water of karstic origin (Box 12, Chapter 3b). In only five out of the past eleven years has the flooding lasted long enough (drying out in July-August) to allow successful breeding. In 2001, the population consisted entirely of adults, giving rise to fears of a rapid decline. The questions which then arose were therefore the following: What is the population size? Is it stable or decreasing? Is breeding once every two or even three years sufficient for the long-term survival of the population? Is it possible to increase the population size and/or its breeding success to reduce the risk of extinction?

Gendre T.

Context: The Great Crested Newt population of the Etang de Valliguières (Gard) constitutes one of the last remaining populations in southern France. Accordingly, this pond has been included in the Natura 2000 network of sites in accordance with the Habitats Directive118. Since January 2000, this population has been subject to monitoring within the framework of LIFE “Temporary Pools”.

Initial number: 50 individuals 1 0,8 0,6 0,4 0,2 0 Every year

Every second year

Every third year

Every fourth year

Frequency of years with early drying out = reproduction failure

54

3. Ecosystem and population functioning and dynamics

habitats or those which are obliged to complete a part of their life cycle here. Knowledge of the biology of these populations and an evaluation of their genetic diversity are indispensable for their management and long-term conservation. It is generally accepted that the capacity of a population to adapt is linked to its genetic diversity. Conversely and paradoxically, a close local adaptation to extreme conditions may result in a decrease in genetic diversity. In order to evaluate the genetic diversity of the populations of a species, several key parameters need to be taken into consideration: the history of the populations, their size, their degree of isolation, the type of reproduction (cross- or self-fertilisation), the characteristics of gene flow and the existence of local adaptations. Prioritisation of populations in relation to their level of interest may prove necessary, to direct the choices of managers towards one population or another when not all, for example, can be subject to conservation measures. In this context, conservation biologists in the 1980s devised the concept of the Evolutionary Significant Unit or ESU: a population unit which merits specific management and high conservation priority, on the basis of a level of adaptive variation determined from ecological and/or genetic data94.

Populations often small and isolated The probability of extinction is greater in small populations, and particularly in a fluctuating environment such as in temporary pools. In these habitats populations are often completely or partly destroyed, for example by early flooding or drying out (the case of the Great Crested Newt, Box 26), which takes place before they have been able to complete their breeding cycle. In small populations, raised levels of inbreeding (genetic drift) may lead to the accumulation of unfavourable mutations which could possibly lead to extinction. This is generally accompanied by a decline in the capacity for adaptation (selective value) of individuals. Small population sizes therefore constitute a risk for species due to the risk of chance extinction linked to severe environmental fluctuations and to the reduction of the capacity to adapt as a result of inbreeding. Some of the biological characteristics of species such as the type of reproduction (cross/self-fertilisation), dispersal (of pollen and seeds) or size of the seedbank for plants, may accentuate or reduce this risk.

Box 27. The paradox of Artemisia molinieri Artemisia molinieri is a rare species, endemic to three temporary pools in the Var and classified as in danger of extinction261, 285. The two main populations of this wormwood are confined to the temporary lakes of Gavoty (Besse-sur-Issole) and Redon (Flassans-sur-Issole), included in the LIFE “Temporary Pools” project. Torrel et al.389 carried out an ecological and genetic study of the two main populations of Artemisia molinieri with the aim of evaluating the threats faced by the species and of formulating conservation measures. The results were as follows: • At the two sites Artemisia molinieri is very abundant (several thousand individuals) and is the dominant species. • Genetic diversity is unexpectedly high for a plant with such a limited geographical distribution. In addition there is no indication of any genetic imbalance (drift). • The two populations, 4 km apart, are genetically very similar, which indicates that there is gene flow (interchange of pollen or seeds) between them, or that they have only recently become isolated. • Levels of pollen viability (10% at Redon and 30% at Gavoty) and of seed germination (4% and 14% respectively) are low in both populations. The low fertility of the Redon population may be partly linked to infection of the inflorescences by a fungus and to environmental conditions (high concentration of nutrients*, irregular flooding, anthropogenic effects, grazing, etc.). In these conditions, Artemisia molinieri propagates itself mainly vegetatively, by means of its vigorous stolon system. The low sexual reproductive rate appears to be sufficient to maintain dense populations and a wide genetic diversity. Torrel et al.389 concluded that the conservation measures should principally involve maintaining the condition of the two lakes (legally protected status and/or acquisition by a public body) combined with continued monitoring of the populations. In 2000, half of Lake Redon was ploughed, destroying part of the Artemisia molinieri population and allowing the appearance of species of high natural-heritage value, such as Lythrum tribracteatum, Damasonium polyspermum and Heliotropium supinum1. This lake is extensively grazed by 200 sheep. Finally, Artemisia molinieri is paradoxical in that it is a rare species with the habit of a dominant, exclusive species: the future of the other species beneath the covering of Artemisia molinieri is uncertain. Given its high degree of endemism, Artemisia molinieri presents a conservation issue of high priority compared with equally protected but much less rare species with which it shares its habitat. Gauthier P., D. Rombaut & P. Grillas

The isolation and small size of the populations impose strong constraints on their dynamics. For individuals, the issues are to pass on descendants capable of maintaining the population and to disperse them among several sites to avoid the risks of accidental local extinction. Sexual reproduction incurs costs286 due to the necessity of searching for partners and due to the fact that only one copy of the genes is passed on. In compensation, it reduces the inbreeding depression*, thereby increasing the “quality” of the descendants and their chances of being successful. Many animal and plant

Roché J.

Consequences of isolation for reproduction and dispersal

Artemisia molinieri, an endemic but dominant species at Lac Redon (Var, France)

55

Mediterranean temporary pools

Box 28. Parthenogenesis: an efficient means of populating the habitat 1. When flooding commences, the resting eggs of Cladocera buried in the sediment hatch and each gives birth to two amictic females (diploid but incapable of mating). 2. These females give birth by parthenogenesis to young (ovoviviparity) or to eggs capable of hatching immediately. These eggs hatch to produce amictic females and so on. This type of reproduction has the advantage of producing a large number of individuals at the lowest cost (3 to 45 per female depending on species and environmental conditions). 3. When the environmental conditions become more severe (increase in solute concentration, temperature etc.) the amictic females produce mictic females (diploid and capable of mating), as well as males (often of smaller size than the females).

56

■ Species from the other habitats ■ Species from temporary pools 100 Percentage (%)

species of temporary pools are able to multiply without using cross reproduction: some invertebrates are parthenogenetic (Box 28) and self-fertilisation is common among plants. In temporary pools in the San Diego area (USA) for example, 12 species out of 20 are autogamic*417. At the Roque-Haute Nature Reserve, the populations of Scirpus maritimus (auto-incompatible) produce no or few seeds due to their isolation and to the lack of pollen originating from neighbouring pools75. The specialist plant species of temporary pools tend to disperse their pollen and fruits less effectively than the generalists* (see below). With reduced rates of gene flow, there should be a greater degree of differentiation between populations than for the generalist species. The poor dispersal (a few centimetres or tens of centimetres) may result in the appearance of genetic differences within a single pool. Indeed, Linhart236 demonstrated the existence of adaptive genetic differentiation between populations of Veronica peregrina separated by two to five metres in temporary pools: plants in the centre of the pool were adapted to strong intraspecific competition in a wet, predictable environment, while those at the edges were adapted to a high level of interspecific competition in a drier, more unstable environment. Dispersal leads to the colonisation of new sites and prevents the extinction of species or of genes. Eggs and seeds allow the dispersal of individuals while the mobility of pollen or gametes ensures the dispersal of genes. In the short term, in particular in island habitats, the capacity for dispersal may be selected against: the probability of success for a plant may be greatest in the same place where previous generations have grown. Populations colonising new isolated habitats may very rapidly lose the characteristics favouring their dispersal. A reduction in dispersive capacity was observed among several species of Asteraceae on small islands after only about ten years following their introduction69, 83. Low numbers facilitate these adaptations. This reduction in dispersal mechanisms has also been observed among the plants of temporary pools417 (Fig. 20). At the scale of the Mediterranean, the colonisation of very widespread sites by similar suites of plants and animals nevertheless suggests that long-distance dispersal does take place, via birds, the wind, etc. Spores, seeds and invertebrate eggs may be carried, sometimes over great distances, in the soil stuck to birds’ feet, or may pass undamaged through their digestive systems143, 308.

80 60 40 20 0 Species without dispersal mechanism for seeds

Species with seeds retention mechanism

Figure 20. Percentage of species with no dispersal mechanism and with mechanisms for the retention of seeds in the plants of temporary pools and other habitats in California (based on Zedler417)

This is likely to facilitate the colonisation of new sites and the flow of genes between populations. In arid or semi-arid environments where temporary pools are the preferred stopover sites for waterbirds208, the dispersal distance will depend on the duration and the length of their flights. Over shorter distances, other vertebrates such as cattle380, wild boar, rats48 or rabbits418 are also agents for the dispersal of seeds or macrocrustacean eggs. The role of amphibians should be studied40, 380. Champeau & Thiéry74 observed the transport of crustacean eggs by Saharan winds from North Africa to southern Europe. They explained the existence of a south-north gradient in the distributional area of some species as resulting from a gradient in fallout rates related to the mass of the eggs. The heavy eggs of Triops numidicus fall out, for example, in Sicily and Majorca while smaller eggs, such as those of calanoid copepods, fall out further north, towards Corsica (Fig. 21). The seeds of Elatine brochonii are so small that they may be assumed to be carried by strong winds.

4. Fertilised by a male, the mictic female lays a dormant egg which requires a maturation phase (sufficiently long period of drought) before hatching. These eggs persist for a few months to several years, buried in the sediment while the environmental conditions remain unfavourable, before hatching Parthenogenesis is a common phenomenon in permanent (stable) habitats where some populations (cladocerans, rotifers) can develop in the complete absence of males and dormant eggs. On the other hand, when the conditions become more severe, the sex ratio (ratio of the number of males to the number of females) is close to unity and the survival of the species depends mainly on the production of resistant stages through sexual reproduction. Gauthier P. & A. Thiéry based on Peters & Bernardi295

3. Ecosystem and population functioning and dynamics

Maxi ø 100 µm Maximum distance of fallout of calanoid copepods cysts

Maxi ø 600 µm Maximum distance of fallout of Triop numidicus cysts

High altitude saharian winds 600 - 1500 m

0

500 km

Calanoid copepods

Triop numidicus

Figure 21. Distribution map for the fallout of crustacean resting eggs on a size gradient (Modified, based on Champeau & Thiéry74)

Figure 22. Cycle of Cladocerans/Daphnidae

Is carried out x times

2 - Increase in the number of amictic females (2n)

3 - Appearance of small males (2n) and mictic females (2n)

Deterioration in environmental conditions: light, [ions] , [02] , T° , populations density

2 - Increase by already hatched eggs or ovoviviparity

4 - Cross fertilisations = resting eggs (sexual) Water level

1 - Hatching of amictic females

■ Water ■ Sediments

[ ] Concentration 02 Oxygen T° Temperature Decrease Increase

57

Mediterranean temporary pools

change (acting as a brake on evolution) and limits the risk of a rapid reduction in diversity64. In temporary aquatic habitats, the banks minimise the consequences of fluctuating population sizes and allow the maintenance of their genetic diversity. The genetic diversity of the existing vegetation does not represent a random sample of that of the seedbank128. It results from selection which may originate, for example, from the elimination of consanguineous individuals (counter-selection) or from differing germination rates depending on genotype* (environmental germination filter).

Box 29. Dispersal by birds In the temporary pools of the Doñana National Park (southwest Spain), Figuerola143 studied the transport of seeds, spores and eggs by birds. He observed a significant level of external transport, on the plumage and feet, of six bird species: two ducks, two wading species and two rallids. Seeds adhere more readily to the plumage and eggs to the feet. Even some seeds lacking dispersive adaptations (Ruppia) were transported. Internal transport also played an important role, with about 65% of bird droppings collected containing undigested, viable propagules*, belonging to seven plant genera as well as crustaceans and bryozoans. Waterbirds were still consuming and transporting a large number of propagules in mid-winter, five months after the peak of seed production144. During premigratory fasting, birds increase the retention time of the propagules (16 hours), thereby increasing their dispersal distance. Waterbirds are probably the main dispersal agents for eggs and seeds within, to and from the temporary pools of Doñana169.

Management implications Estimating the size of populations is of fundamental importance during the implementation of management measures. It is often considered that a threshold level of 100 actually breeding individuals is necessary in a population243, i.e. 300 to 1000 potentially breeding individuals. Below this threshold, populations run a serious risk of extinction after 50 to 100 generations as a result

P. Gauthier & P. Grillas Box 30. Population genetics of Marsilea strigosa at Roque-Haute Marsilea strigosa is a rare species, endemic to certain temporary pools of the Mediterranean Basin. Its genetic variability has been analysed at the scale of the whole of the Mediterranean and at the scale of the very fragmented metapopulation* at the Roque-Haute Nature Reserve (Hérault, France). The studies show that Marsilea strigosa is self-fertile. At the Mediterranean scale, marked differentiation between populations implies very limited or no gene flow. More surprisingly, gene flow appears also to be very limited between the various pools at Roque-Haute, despite their close proximity (a few tens of metres in general). The superficial similarity of the pools to one another conceals a marked degree of genetic variability in the Marsilea strigosa populations: some of them only contain one genotype* whereas others include all the genotypes recorded at Roque-Haute.

The seedbank, population dynamics and genetics In the very variable environmental conditions of temporary pools, some species of plants and crustaceans have evolved to produce organs which persist for more than one season in the soil (Chapter 3, Box 32) to form banks of seeds, spores or eggs. These banks allow populations to persist even when there are repeated reproductive failures over several consecutive years. In Morocco, for example, the years when Elatine brochonii appears in the dayas (Fig. 23) are the years with most rainfall, the seeds remaining dormant during the other years326. The bank of seeds or eggs increases the effective size of populations and their genetic diversity. By increasing genetic diversity and by mixing together in a given year individuals from several preceding generations, the bank reduces the rate of evolutionary

based on Vitalis et al.406

Figure 23. Interannual variation in the abundance of Elatine brochonii in two dayas in Morocco

9 8 7 6 5 4 3 2 1 0 1997

58

Large pool of Mamora

Mean abundance

Mean abundance

Daya of Benslimane

1998

1999

2000

2001

2002

2003

9 8 7 6 5 4 3 2 1 0 1997

1998

1999

2000

2001

2002

2003

3. Ecosystem and population functioning and dynamics

Box 31. Rare or threatened species There are several ways of being rare (Tab. 13). For very specific habitats such as temporary pools, the rarity of species will be more especially linked to the rarity of their habitat (rarity in terms of distribution rather than numbers). Isoetes setacea, for example, is found only at a few scattered sites, but often in large numbers328. However, rare species with small numbers of individuals may also be found in temporary pools (for example Marsilea at Roque-Haute) which, in addition to the scarcity of potential sites, have to face demographic and genetic problems

associated with the limited number of individuals. Rare or threatened species often have low or zero levels of genetic variability, generally resulting from the passage of populations through genetic bottlenecks which limit the intra-population diversity and from the absence of gene flow between the residual populations. It is generally considered that a specialised species, highly adapted to a particular habitat, will be more vulnerable than a generalist* species. However, the increasing rarity of this favourable habitat (isolation) will select for genes which convey a decreased capacity for dispersal, which in turn has a good chance of favouring adaptations appropriate to the site. Gauthier P.

Table 13. Types of rarities in some plants present in temporary pools (based on Rabinowitz et al. 317) Non-specific habitat Size of populations Locally high

Everywhere low

Species with a wide distribution range

Very specific habitat Species with a small distribution range

Common Ranunculus ophioglossifolius Knickxia commutata

Marsilea batardae Morisia monanthos

of the increased probability of the occurrence of deleterious mutations. The protection of populations with numbers lower than these thresholds cannot be guaranteed, and management activities should concentrate on increasing their numbers. The size criterion is often decisive in deciding whether or not a population requires reinforcement. This assessment will be facilitated if the following are known: the degree of geographical isolation, the history of the population, the mode of reproduction of the species being studied, the dispersal of propagules* or pollen, the evolutionary history of the species and its populations (increasing or declining), and the existence of a seedbank. Knowledge of the genetic diversity of the population may also prove to be important. In the long term, a low level of genetic variation (drift) may decrease the potential for adaptation by the population to environmental changes. However, populations having a low level of local genetic diversity may be important in maintaining the overall variation of a species, particularly if they reflect local adaptations. Depending on the specific case, various management principles should be applied for the reinforcement of temporary pool populations. In the case of residual populations, reinforcement based on individuals originating at the same site (after ex-situ breeding) or at

Species with a wide distribution range

Species with a small distribution range

Illecebrum verticillatum Isoetes velata Callitriche brutia

Artemisia molinieri Ranunculus rodiei Apium crassipes

Pilularia minuta Damasonium bourgaei Marsilea strigosa

Teucrium aristatum Laurenbergia tetranda

very close sites should be favoured, to retain local adaptations and especially to avoid failures associated with the poor degree of adaptation of introduced populations. Reinforcement using more distant populations may nevertheless prove necessary if the local populations are too genetically impoverished or cannot be produced ex-situ (numbers too reduced, uncontrolled cultivation or livestock rearing). In the case of metapopulations* (for example newts, see Box 33), interchanges may be more readily considered, especially among sites within the metapopulation. During reintroduction projects carried out following local extinctions, the source populations should be chosen with care, especially in relation to parameters of habitat, geographical proximity and ecology. In terms of the overall conservation of species, the marked degree of isolation of the populations must be taken into consideration. The greatest possible number of populations will need to be preserved to ensure the survival of the widest possible range of genetic and phenotypic diversity of the different species. While some populations must inevitably disappear, it would seem essential to protect those which are in good functional condition, i.e. of a sufficiently large size, breeding regularly and, in the case of plants, having a bank of viable seeds.

59

Mediterranean temporary pools

Box 32. Predicting the unpredictable: drought-resisting

strategies in invertebrates For an aquatic species, life in a temporary pool entails responding or adapting to the disappearance of its natural habitat. Most insects emigrate to leave a biotope which has become inhospitable or to colonise a new biotope. However, a significant proportion of aquatic invertebrates have developed adaptive strategies, among which the production of resistant forms (ecophases*) is one of the most remarkable. These organisms are classified as residents, as opposed to migrants. Many resident taxonomic groups are able to colonise temporary pools, such as sponges (Spongilla) Cnidaria (hydroids), Platyhelminthes (Rhabdocoela of the genus Mesostoma), nematodes, the Oligochaete annelids Naididae and Tubificidae, rotifers, the bryozoans Plumatillidae, and among the crustaceans, Branchiopoda (Cladocera), Ostracoda, and cyclopoid, calanoid and harpacticoid copepods.

Type 1 resistant forms fulfil several functions: • the provision of an egg bank similar to the seedbank, allowing rapid colonisation of the habitat as soon as water appears; crustaceans are the first to colonise the pool and are in this respect true pioneers*, • dissemination by wind (anemochory*) and by animals (zoochory). The eggs of cladoceran and anostracan branchiopods have specific structures and morphologies (Fig. 25), enabling species to be identified278, 287 even when the habitat has dried out (Chapter 6f). Thiéry A. Figure 25. Morphology under a scanning electronic microscope of the cysts of seven species of macrocrustaceans in the Provence region

Various modes of resistance may be distinguished: Type 1: Dormant diapause* eggs are found in branchiopod, ostracod and copepod crustaceans, ephippia in cladocerans, statoblasts in bryozoans and gemmules in sponges. (Fig. 24). Type 2: Dehydration of adults or larvae may be observed in nematodes (Fig 24) and bdeloid rotifers. Larval or adult stages may also survive with reduced metabolic rates in the sediments; this is true of the larvae of Odonata (Sympetrum striolatum: five weeks in the sediment190), chironomid Diptera (Polypedilum pharao375), and Coleoptera which will pupate in dry conditions, such as Berosus375. The reactivation of these quiescent* organisms is directly stimulated by the rehydration of the sediments. Type 3: Quiescent* (also called dormant) larval stages among calanoid copepods resume their development immediately water levels begin to rise.

2

1

3 100 µm

6 4

200 µm

100 µm

7

5 1. Branchinella spinosa

3. 4. 5. 6. 7.

The Caban marsh

2. Linderiella massaliensis Endemic to 4 pools of Provence

Branchipus shaefferi Chirocephalus diaphanus Tanymastix stagnalis Imnadia yeyetta Lepidurus apus

Figure 24. Invertebrate resting eggs

0

100 µm

Spongiae

60

Bryozoan

0

0

100 µm

200 µm

Branchiopod Triops

0

0

500 µm

100 µm

Daphnia (cladocera crustacean)

Nematode

3. Ecosystem and population functioning and dynamics

Box 33. Inter-pool movements by newts

Jakob C.

In the network of pools at the Roque-Haute Nature Reserve, Jakob196 individually marked 470 Marbled Newts (Triturus marmoratus) using electronic tags, allowing their movements to be tracked from 1998 to 2000 (Fig. 26 and 27). In a single year, newts moved an average of 27 m and a maximum of 163 m to reach another flooded pool. Between years, the mean distance moved was 33 m and the maximum 168 m. A study in the Rhône valley (Lyon) at pools separated by increasing distances264 showed that the migration distance between populations of Alpine Newts (Triturus alpestre), Palmate Newts (T. helveticus) and Great Crested Newts (T. cristatus) is relatively short. Complete isolation could be observed among populations separated by more than 350 m. Jakob C. Monitoring by radio-tracking the movements of Triturus marmoratus at Roque-Haute

1

19 1

1

52 1 4

4

1

36

12

1

1 3 20

1

Figure 26.

Number of newts which moved to another pool

Number of newts marked at the first capture campaign

Movements of Great Crested Newts marked and recaptured during a period of flooding (1998) at RoqueHaute

61

Mediterranean temporary pools

Figure 27. Interannual movements of Great Crested Newts marked and recaptured at Roque-Haute (between 1998 and 1999, between 1999 and 2000, and between 1998 and 2000)

0m

88 m

62 m 0m 43 m

sol

14 m 17 m

0m 30 m

0m

40 m

0m

168 m 0

35 m Movements in m

62

4. Threats to Mediterranean temporary pools Gauthier P., P. Grillas & M. Cheylan Temporary pools often have a scattered distribution and because of their small surface area are potentially easy to destroy. However, from a historical perspective, human action on pools has been contradictory: on the one hand, multiple anthropogenic pressures degrade or destroy pools; on the other hand, many pools are of artificial origin, created for various purposes, including watering holes for livestock373 (Box 34). Today, despite the absence of precise data, it is clear that the destruction and degradation of Mediterranean temporary pools occurs more frequently than their creation. The hydrological characteristics (duration, depth, dates) and low productivity (few nutrients*, summer drought) of temporary pools are the most important factors for the conservation of the species and characteristic communities they contain (See Chapter 3). When they affect these factors, human activities have an impact on the conservation of the species which they host. A distinction should be made between damage leading to the direct destruction of pools (urbanisation, infilling, etc.) and degradations or perturbations (for example partial drainage, pollution) which, though less irreparable, still modify their ecological functioning. The introduction of invasive species, the closing-up of the habitat and natural aggradation* also disrupt the delicate balance between these habitats and the species they contain. Although most of the threats faced by temporary pools are common to the whole of the Mediterranean region, a contrast can be observed between the countries of the North and those of the South. As they were useful for an agricultural economy based on extensive exploitation, the pools are of limited interest today in most European regions, where they have been abandoned or destroyed284, 373. In the countries of the South, however, they retain their usefulness in the current economic context. Their importance, however, risks being reduced as a result of economic development.

Box 34. Temporary pools in southern France: a balance

that is sometimes positive in terms of quantity but always negative in terms of quality There is no current research enabling the decline of temporary habitats to be measured. Also, though in some sectors of southern France such as the Massif des Maures (Var) or the Causse d’Aumelas (Hérault) there are certainly more creations than disappearances, these are not of equivalent quality. In the Massif des Maures and Plaine des Maures, pool creation has two main functions: small water cisterns for the Défense des Forêts Contre les Incendies (DFCI) and pools used for hunting purposes. Some support good populations of amphibians, especially pioneer* species (Natterjack Toad, Common Toad, Parsley Frog) as well as rare species (Spadefoot). On the other hand, they are of little interest from the botanical point of view, as they are often dug into soil and are therefore muddy. On the Causse d’Aumelas, many pools used for hunting purposes, which are also attractive to some amphibians, have been created over the last 20 years without any destruction of pre-existing pools being observed (Lavognes type, see Chapter 2a). In Languedoc, Chaline72, who in 2001 continued the inventories of pools conducted in 1974 by Gabrion153, observed that six pools out of the 94 studied had disappeared. At the same time, far more pools had been created. Among those, Chaline distinguished: • Pools used as watering places, usually covered and thus not very interesting for fauna and flora (essentially on the Causses). • Pools used for hunting purposes, small, frequently concretelined, generally fairly deep and more or less unvegetated. • The hill reservoirs used by the DFCI, supplied by rivulets, generally deep and fairly large in size. These new types of pools attract some pioneer amphibians of unstable habitats (Natterjack Toad, Parsley Frog) or generalist* amphibians (Common Toad, Palmate Newt, Stripeless Tree Frog) but are globally less rich than the traditional pools of this region. Cheylan M.

Over the past 50 years, there has been a vast increase in urbanisation around the Mediterranean, related to demographic growth and the development of tourism. Temporary wetland areas in periurban habitats are faced with the threat of infilling during housing or road development. In Languedoc-Roussillon, the majority of local declines and extinctions of rare plants have been caused by the direct destruction of habitats (urbanisation) and the intensification of land use228. Near Agde, the Rigaud pools disappeared during the construction of a housing estate260 and those at NotreDame de l’Agenouillade (Agde, Hérault) are surrounded by urbanisation. The pools of the Plateau de Vendres (Hérault) and Rodié (Var) have been degraded or partially destroyed by road infrastructure. In Malta as in Morocco, the disappearance of pools following urbanisation is frequent near towns21, 222, 322. The increasing rarity of sites has significant consequences for populations, notably of amphibians, by reducing the extent of interchange between populations and thus their long-term survival

Roché J.

Destruction of sites

On the Plaine des Maures, the construction of a golf course has destroyed numerous temporary rivulets with Isoetes duriei

63

Mediterranean temporary pools

(Chapter 3d). In some cases, the disintegration of the landscape can lead to the total extinction of all species. This is the case, for example, in the Ebro Delta in Spain where, following extreme artificial modification of the landscape, all amphibians have now disappeared, even the most resilient species such as the Iberian Green Frog (Santos, pers. com.). In contrast, the Camargue Delta has lost none of its original species, thanks to the preservation of important natural areas.

In the Mediterranean region, public-health interests have justified the draining or infilling of pools, which as “sources of disease” are feared by humans. Similarly, pools have been dried out in Morocco263 and Malta182 to combat mosquitoes (Anopheles labranchiaei), vectors of malaria. Temporary wetland areas are also filled in or drained to increase arable areas. Intensification of agriculture was the main cause for the disappearance of pools in Spain between 1955 and 1980 (Medina, pers. com.) and in the Costières Nîmoises (France) during the same period310. Pumping from the water table for agriculture and the supply of drinking water to urban areas, for example in the Donãna National Park in southwest Spain357, Malta182 and northeast Algeria105, leads to the early drying-out of these habitats, thus imperilling their characteristic communities of plant and animal species.

Box 35. Roads: impassable barriers The construction of linear infrastructure (roads, motorways, railway lines, etc.) inevitably causes the destruction of numerous forests, meadows and wetland areas. Roads cause heavy mortality among amphibians. This has been assessed at between 34 and 61% whilst crossing a road with traffic of 3200 vehicles per day, and from 89 to 98% on a motorway (traffic greater than 20,000 vehicles per day)184. After a stormy night, 456 Palmate Newts, 314 Stripeless Tree Frogs, two Natterjack Toads and two Marsh Frogs were found squashed on 60 metres of a road with little traffic, near Montpellier79. A major ongoing study, begun in Catalonia in 2001 should enable this mortality to be measured throughout the whole of a region239. Impassable for many amphibian species36, 231, roads are barriers which reduce or remove the opportunities for interchange between the populations situated on either side of them353. This isolation makes the populations more vulnerable to the risk of extinction, whether this is due to genetic or demographic causes or random environmental accidents412. Over the last 15 years, two of the four populations of Western Spadefoots known in the Var département have thus been wiped out with no hope of recolonisation, given the distances separating these sites from the nearest populations. In Germany, populations of Common Frogs (Rana temporaria) have shown genetic impoverishment following the creation of a motorway320. Gauthier P. & M. Cheylan

64

Tan Ham L.

Hydrological perturbations

Banalisation of the vegetation at the Grammont pool (Hérault, France) following its permanent flooding

The extraction of raw materials for construction results in an increase in the duration of flooding and turbidity of pools in Morocco, accompanied by their impoverishment in rare species325. The creation of reservoirs for irrigation or fire protection (DFCI), by overdeepening or banking up, causes permanent flooding of temporary habitats. Several pools which host rare crustaceans (Branchipus cortesi) have thus been overdeepened in Portugal and have lost their temporary ecological nature244. The SaintEstève pool in the Pyrénées-Orientales and the Grammont pool near Montpellier have also been transformed into permanent pools following hydrological modifications in their catchment area11, 230, 284. These hydrological changes lead to a reduction in floristic richness, notably of bryophytes* (Hugonnot & Hébrard, pers. com.) and to the disappearance of rare species and their replacement by a more invasive aquatic flora based on helophytes* (Typha latifolia, Scirpus maritimus, etc.). However, an increase in the duration of flooding of the pools can prove to be favourable to the aquatic fauna (amphibians, insects, crustaceans) by enabling it to complete its breeding cycle.

Perturbations by fire Fire is a major disruptive factor in the Mediterranean region. Its impacts, though little studied, are probably variable: direct on the fauna, flora and seedbank, and indirect on the hydrology, sedimentation and exotic species, for example. In the case of temporary pools and streams, fire has positive effects in the sense that the destruction of woody species and the opening-up of the landscape favour Mediterranean species. It also has negative effects on populations and on the habitat (infilling by ash and silt, etc.) which can affect all of the species present. The plant biomass, the date of the fire and the dampness of the ground are factors likely to affect the temperature of a fire and its consequences for the species and their perennating organs. Perennials possessing rhizomes or underground bulbs are resistant to the passage of fire. Thus Artemisia molinieri does not seem to be affected by the winter burning of its dry stems. Similarly, large rushes or Scirpus produce new leaves in the weeks following a fire. The passage of fire probably has a more significant destructive impact on superficial seedbanks and perennials lacking underground perennating organs (Cistus, for example).

4. Threats to mediterranean temporary pools

In Catalonia, a study in the Garraf Natural Park has shown a reduction in the species richness and abundance of amphibian larvae in pools affected by fire with significant differences between species: the Stripeless Tree Frog (Hyla meridionalis) was the most affected, while the Parsley Frog and Iberian Green Frog were only slightly affected82. Tree-dwelling species are more sensitive to fire than the species of open habitats, which are less affected, and even favoured in the mid term. In the Serra de Grândola (Portugal), one year after a fire, the amphibian community was significantly altered with a notable reduction in the number of urodeles Triturus marmoratus and Salamandra salamandra92. In the Maures, immediately after a fire, one of the rare species still present is the Marsh Frog (Rana ridibunda), an invasive species with a high reproductive capacity (Cheylan, pers. com.). However, the time scale is too short to assess the mid-term impact of fires on amphibians. To overcome these shortcomings, a study is planned on the pools of the Natura 2000 site “Bois de Palayson-Colle-du-Rouet” following the fires of the summer of 2003. Fires can also modify the hydrological functioning of temporary pools and streams (increase in the flooding regime, evapotranspiration, etc.) through increased erosion of the catchment area and the input of sediments resulting from this (for example in the Maures80, 260, 311). In small streams with shallow beds, a temporarily high flow can remove most of the sediment. On the other hand, in larger streams the sediments persist for a long time in deep basins, thus modifying their hydrological characteristics (capacity to support the European Pond Terrapin, for example). In pools, sediment accumulation increases with the size of the catchment area. Indirectly linked to fires, forestry operations for reforestation and the development of fire defences, by altering the topography of the ground, can compromise the functioning of the hydraulic network of temporary pools and streams (for example, the hydrological network of the Bois de Palayson or the Plaine des Maures260).

Invasion by competitive plants (woody plants, helophytes*, etc.) The cessation of agricultural practices, particularly the extensive grazing of livestock, results in the “closing-up of the habitat”, i.e. the colonisation of herbaceous habitats (grasslands, meadows) by woody species. A simple increase in the density of herbaceous cover constitutes a threat for less competitive annual plants (Box 49, Chapter 5c) and for amphibians dependent on open landscapes: Western Spadefoot (Pelobates cultripes), Natterjack Toad (Bufo calamita) or Parsley Frog (Pelodytes punctatus). The bryophytes of temporary pools only survive for a very short period when they are subjected to shade or competition with colonising grasses (Hugonnot & Hébrard, pers. com.). On the other hand, irregularly grazed habitats are often very rich in bryophytes. Flooding (height and duration) limits the expansion of woody species into temporary pools. However, species tolerant to flooding grow on the border and in the shallow areas of the pools. The

Roché J.

By opening up the habitat, fire favours the establishment of exotic pioneer species162. The destruction of the belt of woody species surrounding pools could explain the spread of Dittrichia viscosa in the pools of Tre Padule de Suartone in southern Corsica241, 242. Modifications to nutrient dynamics and the level of released toxic compounds (phenols, tannins) have not been studied ; nonetheless, they also constitute potential threats for species.

At Roque-Haute (Hérault, France), the growth of woody plants, following the cessation of grazing, has had a negative impact on populations of Isoetes setacea

spread of woody species in and around temporary pools generally results in the cessation of grazing by livestock. This causes a reduction in solar radiation and in temperature, which can slow down the growth of herbaceous plants (Box 46, Chapter 5c). In addition, shade, reduction in wind speed and water temperature reduce evapotranspiration in winter and thus tend to increase the duration of flooding. Conversely, the presence of certain species which are major consumers of water can lead to a great increase in evapotranspiration during the growth season and accelerate the drying out. Pools are thus dried out by the planting of Eucalyptus, as is the case in Portugal for paper production244, 300, or in Morocco for timber or firewood, or in order to “clean up” these zones, which are often considered as unhealthy (Rhazi L., pers. com.).

Input of nutrients The direct input of nutrients into pools is probably rare in France even though the margins of some pools are cultivated. Some Moroccan dayas, on the other hand, are still used for washing by local populations who introduce phosphate-rich washing powders (Rhazi et al., 2001). The accumulation of livestock faeces within pools or their immediate periphery is also a potential source of nutrients, the impact of which remains to be evaluated. When temporary pools take the form of islets in the middle of large cereal fields or vineyards, agriculture represents a threat through its indirect inputs of fertilizer via run-off water or underground water. The accumulation of nutrients from agriculture has been observed in the clayey substrate of Moroccan dayas325. A number of laboratory experiments have shown that amphibian larvae feed less, move less quickly and exhibit imbalances, malformations and an increased mortality rate when low levels of nitrates and nitrites are added to the water249, 409 (Box 36). In Spain, three species of amphibians have been revealed to be very sensitive to ammonium nitrate: Common Tree Frog, Painted Frog and the Common Toad287. In the Common Tree Frog, a mortality rate of 30% has been observed for concentrations of 50 mgL-1 (legal concentration permitted for human consumption). The other species, though less sensitive, nonetheless show slower growth as well as developmental anomalies.

65

Mediterranean temporary pools

Box 36. Amphibians and chemicals The eggs and larvae of amphibians are particularly exposed to toxic effects in aquatic habitats but the adults, in aestivation or hibernation, can also be contaminated. Depending on the species, the stage of development and the level of contamination of the habitat, amphibians assimilate toxic agents through different routes: the skin, inhalation and/or direct or indirect ingestion (consumption of the target insects of the pesticides). Even though the concentrations of pesticides in the environment rarely reach the lethal doses determined in the laboratory, sub-lethal effects can have serious consequences particularly for the larvae (malformations, disrupted feeding or movement, delayed growth, etc.) leading, sooner or later, to their disappearance (Fig. 28). In amphibians, pesticides can interact with the endocrine system. The temperature, UV-B radiations and pH are known to amplify their harmful effects. Also, it seems that the presence in the environment of several chemicals may have a cumulative effect.

When pesticides must be used in an agricultural area, it is particularly important to avoid breeding periods (phases of migrations to and from breeding sites, the presence of eggs and larvae in the water, dispersal phase of juveniles) and migration (movements of adults between summer and winter sites), and to exercise caution in applying the substances to avoid unnecessary contamination of surrounding areas, including pools. Improving agricultural techniques and limiting the risks of contamination by filtering the discharge water before it can reach water bodies are two fundamental strategies to limit contamination. Creating buffer zones on the margins of cultivated areas is one of the most effective means of reducing contamination. Gauthier P. & M. Cheylan based on Scoccianti355 et Blaustein & Kiesecker35

Use of agrochemicals (pesticides and fertilizers)

Exposure of amphibians to lethal doses

Effect on other species (insects, etc.)

Exposure of amphibians to sublethal doses

Assimilation through the trophic chain

Malformations Death

Decreased food supply Alteration in activity

Decreased feeding intake

Decreased predator avoidance ability Longer period of time when the larvae remain in the contaminated site

Delay in growth and development

Predation

Longer period of time when the larvae are vulnerable

Decreased intra and inter specific competition ability

Further delay in development Delay in metamorphosis with possible repercussions on the survival rate of newly emerged juveniles

66

Death caused by drying up of breeding site before the completion of development

Figure 28. Possible effects of agricultural chemical substances on amphibian populations

4. Threats to mediterranean temporary pools

Enrichment by phosphorus and potassium can also cause eutrophication of pools, induce algal blooms and favour competitive plant species to the detriment of rare and characteristic species. Béja and Alcazar29 suggest that the proliferation of Reedmace (Typha sp.) in pools in Portugal results from an increased concentration of nutrients. Pollution can also be of urban origin: in central Spain146 and in Morocco (Rhazi, Thiéry, pers. com.), the channelling of urban waste water into temporary wetland areas has been observed. The Opoul pool (Pyrénées-Orientales, France) was used, in the past, as an outlet for a domestic-water purification site210, 284, although we do not know if these inputs have had detrimental consequences for the batrachians or the flora.

Toxic pollutants and dumps With the purpose of combating malaria, insecticide products are poured directly into pools (in Morocco263). Indirect inputs can result from various human activities in the catchment area, notably the pesticides used in agriculture. Roads are sources of various types of pollution, whether as a result of accidents involving vehicles transporting toxic products, by road leachates with a high hydrocarbon content or by products used for road maintenance (herbicides, salts, lime, etc.). In the case of karstic wetland areas, the origin of the contamination can be much further away than the superficial catchment area would suggest (Chapter 3b). The degree of contamination of a site varies above all according to the quantity of chemical products per unit surface area, as well as the size of the surface treated and the persistence of the substances. It is not unusual for the concentrations of toxic substances in small isolated pools (closed systems) situated near agricultural zones to be higher than in larger wetland areas where water renewal is greater. Throughout the Mediterranean, temporary pools are used as dumps for waste and rubble. This dumping leads to a decline in the characteristic bryophytes and causes the appearance of nitrophilous land-based communities with Barbula unguiculata, Funaria hygrometrica, etc., which are very commonplace ruderal species (Hugonnot & Hébrard, pers. com.). The accumulation of pesticides in run-off water represents a high risk for amphibians (Box 36) and aquatic invertebrates166 (Box 37). In some cases, it seems that amphibians have good capacities of resistance to polluting agents. The establishment of amphibian populations in motorway stormwater tanks (Scher, pers. com.), and the persistence of a diverse population in the Opoul pool in the Pyrénées-Orientales, which receives water from a vineyard which undergoes frequent chemical treatments284, seem to indicate this.

Physical disturbance of the sediment Physical disturbance of the habitat (burrowing of wild boar in the sediment, trampling by livestock, the passage of vehicles, input of sediments to the catchment area, digging, etc.) can have, depending on the situation, positive or negative effects on the conservation of the flora and fauna of temporary pools. Physical perturbations can contribute to the reduction of the plant cover and thus, indirectly, favour annual or not very competitive species. When these perturbations become too frequent, particularly during the growing

Box 37. Pesticides and dragonflies The quality of surface water has been greatly degraded for several years now, and dragonflies now seem less numerous; some species even appear to have disappeared101. Recent studies58 show that a number of pesticides chronically contaminate rainwater, particularly Atrazine (herbicide), DEA (deethylatrazine), Alachlor (herbicide), Lindane (γ-HCH) (insecticide) and its isomer β-HCH. Pesticide levels in water can sometimes exceed several tens of mg per hectare (in Atrazine and Alachlor). Though few studies exist in the Mediterranean region, data is available in the surrounding region showing the great sensitivity of dragonflies to pesticides during their aquatic life, i.e. at the larval stages. Methoprene, an insect growth regulator used to combat mosquitoes, causes a reduction in Odonata populations56, 362. Similarly, carbamates affect seven genera of Zygoptera and Anisoptera164. After seven days of application of Diflubenzuron, Zgomba et al.420 observed a 72% mortality rate in Odonata in Yugoslavia. Applications of Bacillus thurigensis, BT serotype H-14, cause similar reactions. The same results have been observed on populations of chironomid Diptera305. Organophosphates cause the death of dragonfly larvae in less than two hours. Fenthion, Bromophos and Lindane are highly toxic to Zygoptera (Lestes sponsa, Ischnura elegans, Coenagrion puella) for which a mortality rate of 40% was recorded in populations in less than 48 hours212. High concentrations of Rotenone eliminate Aeschnidae. Generally speaking, in contaminated water the density of Odonata is reduced by 30% compared with natural habitats370. In Germany, in the Hamburg region, only two species, Coenagrion puella and C. pulchellum, had survived out of the 14 recorded 25 years earlier183. With regard to ricefields, pesticides have been the subject of recent studies: Schnapauff et al.349 show in Greece a negative effect of Propanil (N-(3,4-dichlorophenyl)-propionamide) associated with Parathion (an organophosphate) on the populations of Ischnura elegans. In the Camargue, Suhling et al.366 observed that Sympetrum fonscolombii and Orthetrum cancellatum are clearly affected by treatments which combine Icazon and Alphamethrine (a pyrethroid). Suhling (com. per.) puts forward the hypothesis that Sympetrum depressiusculum, which will soon be added to the IUCN Global Red List and whose larvae used to develop in the ricefields of the Camargue in the 19603 disappeared following the use of insecticides. In the Camargue, Fipronil, the only insecticide currently authorised, is also suspected of causing a reduction in numbers and changes in population structure in half of the species present in ricefields155 (Crocothemis erythraea, Orthetrum cancellatum and O. albistylum). Odonata larvae are good indicators of water quality369, 253. Long-term monitoring of Odonata populations is thus of great importance for habitat management. However, as dragonflies are known for their great capacities for flight, an inventory based on the occurrence of adults is not relevant. The provenance of adults should be verified by the study of the larvae and exuviae, which give proof of successful breeding in the biotope. Thiéry A.

67

Mediterranean temporary pools

On the southern shores of the Mediterranean, the large population increase of recent decades has led to an increase in livestock numbers causing, in Morocco and Algeria, considerable damage to pools and neighbouring natural habitats81, 263, 339. Despite the extensive rearing methods used here, the animals concentrate around the pools. The intense trampling of the livestock breaks down the soils323 which become very unstable, increasing turbidity and reducing the light available for plants. In the pools of the forest of Mamora (Rabat, Morocco), the turbidity caused by the passage of livestock seems to explain the poor development of aquatic and amphibious vegetation during the submerged phase.

Roché J.

season of plants, they can reduce the size of populations, fragment them and prevent plants from completing their cycle and reproducing. Generally speaking, analysis of the impact of perturbations should be made by considering the type of perturbation and the potential impacts on both sensitive populations and competitive species. The creation of ruts by the repeated passage of vehicles, particularly of all-terrain vehicles (cars, motor bikes), can alter the hydrological functioning of pools. Thus, for example, in the Padulellu pool near Porto Vecchio (Corsica), following the repeated passage of 4x4s, run-off increased in the catchment area, resulting in the site of Elatine brochonii being covered with gravel241. At other sites, localised trampling leads to excessive subsidence of the substrate and causes a decline in most species of bryophytes (Hugonnot & Hébrard, pers. com.) and of characteristic angiosperms*. Thus in the Chevanu pool (southern Corsica) which serves as a car park in the summer, the numbers of the annual Lythrum borysthenicum dropped by around 90% between 1991 and 2003 (Paradis & Pozzo di Borgo, unpublished).

Impact of ploughing and grass-cutting on Artemisia molinieri at Lac Redon (Var, France)

Sedimentation Temporary pools are shallow habitats, which make them potentially very sensitive to infilling by sedimentary deposits. These deposits are partly the result of natural processes, the speed of which are a function of the nature of the substrate, the intensity of rainwater run-off (gradient, permeability), the extent of the catchment area and the balance between the processes of deposition and erosion. These processes can be accelerated by human activities (see above, this Chapter). Sedimentation can be predominantly mineral or organic. In the second case, organic material can arise from the pool itself in situations of high productivity (litter from helophytes, trees, etc.), from the periphery, or from the catchment area. Infilling contributes to the reduction in the number of rare species and the establishment of competitive herbaceous species (Scirpus maritimus, Phragmites australis, Paspalum ssp., Dittrichia viscosa, Typha, etc.) and/or woody species, through the reduction of the stress linked to flooding and an increase in the productivity of the habitat. The establishment of these productive plants also contributes to the drying-out of temporary pools357 through the accumulation of organic material and an increase in evapotranspiration. In North Africa, in some cases the processes of infilling of the dayas will be slowed down by the effect of whirlwinds which, during the dry phase, lift and carry off the sedimentary particles accumulated at the bottom of the basin263, 323, 380. Alluvial deposits constitute a particular threat for bryophytes: when a temporary pool is tending to fill in and lose its alternating

68

regime, the 15 to 30 species characteristic of the submersion/ drying-out cycle disappear and leave room for a succession of commonplace species, which are not very numerous and are nonspecialised, forming dense cover. In these conditions, one encounters Amblystegium riparium and Drepanocladus aduncus, which form a carpet of entangled stems, or Bryum pseudotriquetrum for example. These species generally accompany the large helophytes (Typha or Scirpus) (Hugonnot & Hébrard, pers. com.). The deposit of a litter of tough leaves, of Cistus for example, can be a serious obstacle for smaller herbaceous plants, notably the terricolous bryophytes (Hugonnot & Hébrard, pers. com.) or Isoetes328 which become covered up.

The impact of invasive species Colonisation of pools by competitive, often ruderal, exotic plants can engender competition with the characteristic species of temporary pools. Poirion & Barbero303 reported the colonisation of numerous pools and cupules of the Esterel and the Biot massif (Var) by a very virulent South African plant, Freesia alba. In the Maures, Paspalum dilatatum, Panicum capillare and Euphorbia prostrata, the two first species being mainly propagated along the road network, colonise areas of sedimentary accumulation at the bottom of streams and pools (Medail, pers. com.). These species contribute to the loss of habitat and should thus be monitored even if, given their primarily summer or autumn growth season, their

4. Threats to mediterranean temporary pools

impact on the other species of temporary pools probably remains low. In Corsica, there is another South African species, Cotula coronopifolia, which seriously affects most low-altitude wetland areas280, notably the temporary pool of La Tour d’Olmeto (Paradis, pers. com.). The permanent flooding of temporary pools and the installation of low volume dams on temporary streams are generally followed by the introduction of fish, often exotic, which constitute a major threat for amphibians4, 51, 98, 154, 258, 272. For example, in Provence during the 1960s, the pond at Saint Rémy in the Alpilles supported several natural-heritage species for the region (Triturus helveticus, Alytes obstetricans, Pelobates cultripes, Pelodytes punctatus), which have today totally disappeared because of the introduction of fish (Peyre, pers. com.). A similar observation has been made in the region of Cantabria, the Province of La Coruña (Spain), in Algeria and in Languedoc, where the number of amphibians in sites with fish is much lower than that observed in sites without fish. Mosquitofish (Gambusia affinis), introduced into France, Spain and Algeria in the 1970s to combat mosquitoes96, 136, 340, are regularly found in temporary pools where they have a negative impact on certain species of zooplankton (Daphnia spp). In the temporary marshes of the Camargue, the accidental introduction of Three-spined Stickleback (Gasterosteus aculeatus) through irrigation canals has caused the gradual extinction of the largest and most visible (coloured) zooplankton species which are characteristic of these habitats304. The explosion of populations of Louisiana Crayfish (Procambarus clarkii) has had direct negative effects on the vegetation of temporary pools and indirectly on the animal species colonising these habitats by reducing their food resources and impairing their refuge

sites (see, for example, in the Doñana National Park179). In the Paul do Boquilobo Nature Reserve (Portugal), 13 species of amphibians could be observed up to the beginning of the 1990s100, 319. Eleven years after the establishment of the Louisiana Crayfish, only four species could be found, with numbers clearly lower than those observed during the first inventory in 1993. Only Bufo calamita, dependent on very ephemeral pools, not colonised by the crayfish, has increased locally. The impact of the Louisiana Crayfish is sometimes exacerbated by the introduction of exotic fish with significant effects on populations of amphibians such as in the Province of La Coruña (Spain)154 and in the Alentejo Natural Park in southwest Portugal29. In general, these predators attack the eggs and larvae of the most sensitive amphibian species. Some species, however, show resistance to these predators, either through the toxicity of their larvae (Bufo bufo), or by avoidance behaviour (Rana sp., some urodeles). In addition, most batrachians detect the presence of fish by chemical recognition191, which enables them to avoid the sites colonised by the fish. This avoidance, however, results in a loss of breeding sites, which accelerates the decline of the species.

Impact of domestic and game fauna Wild and domestic herbivores have dual and contradictory effects: they can compromise the survival, growth and reproduction of plants yet they also reduce competition and create sites favourable to the regeneration of weakly competitive species (see above, this Chapter “Invasion by woody species”). Negative effects

Box 38. Damasonium alisma and ploughing Devictor112 compared the seedbanks of Damasonium alisma in pools situated on fallow land with those of pools situated in cultivated areas. Despite a density of plants three to five times higher in the cultivated areas than in the fallow areas, the average number of seeds in the soil bank was the same in both areas (an average of about 300 seeds per 250 g sample). In the fallow land, the seeds were found mainly on the surface, while in the cultivated areas they had a more homogenous distribution through the soil profile. The germination rates of the seeds from the fallow land were 70% and 45% respectively for surface and deep horizons, and in the cultivated zone 40% and 80% for surface and deep horizons.

Pozzo di Borgo M. L.

Ploughing can explain this contrasting distribution. In the cultivated part, the seeds produced in the summer, with high germination capacity, are buried by ploughing in the autumn and the seeds found on the surface are of variable ages with a lower germination rate. In the zone on fallow land, the seeds remain on the surface and germinate in the following spring. Ploughing thus has contradictory effects on the seedbanks of Damasonium: positive because through the opening-up of the habitat, it favours the appearance of this heliophilous species, and negative because it buries the seeds which progressively lose their germinating ability. based on Devictor112 Invasion of the Padulu pool (Corsica) by Dittrichia viscosa

69

Mediterranean temporary pools

germination of Crau Germander (Teucrium aristatum) is also closely linked to the effects of livestock (Chapter 5d, Box 49). The increase in wild boar populations (Sus scrofa) is accompanied by increased pressure on habitat, particularly in wetland areas5. Maillard247 was concerned with the Roque-Haute Nature Reserve, where the pool sediments are occasionally turned over by wild boar, perhaps seeking Isoetes bulbs (Rhazi, pers. com.). These disturbances, however, create favourable sites for plant germination and probably play a positive role if their frequency is not too great. On the other hand, wild boar represent a threat for amphibians by disturbing their refuges around pools, as has been observed at Valliguières for example240 (Chapter 3f, Box 26).

Grillas P.

of spring grazing on the flowering and fruiting of some species of temporary pools (Ranunculus sardous, Orchis laxiflora, Agrostis pourretii, etc.) have, for example, been observed in Corsica in the Padulu depression291. Such negative impacts are common in the overgrazed areas of the Maghreb. In Morocco, overgrazing leads not only to degradation of the plant cover, but is also thought to be responsible for the disappearance of rare species313. On the other hand, in the north of the Mediterranean, grazing contributes to the maintenance of certain threatened species: this is notably the case with the Western Spadefoot, a very localised amphibian in southern France, which is closely linked with the action of livestock, as well as the Parsley Frog and the Natterjack Toad. The

In Morocco, overgrazing of the dayas constitutes a threat for the flora (Mamora, Morocco)

70

5. Management and restoration methods a. From site assessment to management plan Perennou C., P. Gauthier & P. Grillas

Site assessment, a prior requirement for any management What is management? “To manage a natural habitat is to act (or not act) to preserve, or increase, its natural-heritage value; this may involve the perpetuation of traditional activities, the use of modern techniques or simply the monitoring of natural change, in order to maintain or to modify an ecological equilibrium according to specific conservation objectives” 331.

Why is management of Mediterranean temporary pools necessary? Various human activities and natural processes act directly or indirectly on the pools and may modify their functioning and affect the species which they support (see Chapter 4). Active management may be necessary to mitigate or correct processes that have a negative effect on the functioning or the biological richness of the pools. Site restoration becomes necessary when the processes of degradation are too advanced.

A framework: the management plan Before taking action (or deciding not to act) at temporary pools, a preliminary phase of discussion and of organising management activities is necessary. More and more frequently, this takes the form of a management plan, which is now a well-known tool. It consists of: • An approach which aims to set out, jointly, proposals for activities which will be useful in the conservation of the site and which are recognised and accepted by all the parties involved: owners, site users, official bodies, organisations. • A document which sets down the results of this approach. The management plan does not consist only of this one document, even if it is formally approved by all the parties involved: if so, it would most often never be implemented by the local parties, who would not feel themselves to be involved, whereas its entire purpose is to be used for the daily management of the site. Management plans may take a number of name and form depending on the context. In France, the Nature Reserves, the lands of the Conservatoire du Littoral or the regional conservatories of sites are served by management plans sensu stricto331. The Objectives Documents for the French Natura 2000 sites are management plans in which owners and site users play an important role397, just as the Water Management and Development Schemes are the equivalent of management plans for small river catchments. The range of titles should not, however, obscure the remarkable consistency of the major logical stages of these management plans, which corresponds to a sequence of questions (see below, this Chapter). More widely in Europe and in the Mediterranean Basin, the same methodological approach is also followed or recommended135. Here the concept of the management

Box 39. Management plans for temporary pool sites in

France The Voluntary Nature Reserve of the Tour du Valat, followed by the Roque-Haute Nature Reserve, were the first two sites in France, rich in temporary pools, to create management plans, in the 1980s and 1990s respectively. Within the framework of the LIFE “Temporary Pools” project, three sites have also developed their own management plans: Notre-Dame de l’Agenouillade, Valliguières and Padulu. The Tre Padule de Suartone having been declared a Nature Reserve in 2000, a management plan for this site should be produced shortly. Finally, a number of sites391 appearing on the list put forward by France to complete the Natura 2000 network have initiated their Objectives Documents. These documents are in the process of being drawn up for 19 sites. Perennou C.

plan will be used in a very general sense including, without specific mention, all the various forms which it may take.

Site assessment and management plan Site assessment is always a key phase for establishing initial hypotheses about the possible ecological changes that are taking place, in order to devise management and monitoring measures to be undertaken in order to safeguard, rehabilitate or recreate a habitat. The general approach of management plans is described here as applied to temporary pools, including the assessment phase.

The stages of the management plan The structure of a management plan (Tab. 14) corresponds to a sequence of questions and answers. Site assessment corresponds to stages 1, 2, 3 and 5. The various stages are detailed below, with the emphasis on aspects specific to temporary pools; more general aspects may be consulted in RNF331.

1. Context The area involved should firstly be defined, making the distinction between a central zone, (the pool or stream) and a zone of influence corresponding to the functional space356. This is “the area close to the wetland, directly dependent on and having functional links with the wetland, within which certain activities may have a direct, strong and rapid influence on the habitat and may seriously affect its continuing survival”. The zone of influence is defined according to technical criteria: supply from underground or surface water, inputs of pollutants, source zone for sediments, home ranges of mobile species, etc.356 Its dimensions are therefore variable depending on the size, type and geographical situation of the pool, the factors involved and the home ranges of the species which it is wished to conserve. It may be very large in respect of some parameters. For example, the quality and quantity of water in pools in karstic areas (Valliguières pool) depends on the groundwater throughout the whole region; they may be affected by very distant sources of pollution or hydrological perturbations.

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Mediterranean temporary pools

Table 14. The major logical stages of the management plan

What is the general working context 1. GENERAL CONTEXT OF THE SITE What does the site consist of? 2. DESCRIPTION AND ANALYSIS OF THE SITE What is its value? 3. EVALUATION OF NATURAL AND SOCIAL HERITAGE AND OF ECONOMIC VALUES What future is desired? 4. IDEAL LONG-TERM OBJECTIVES What are the constraints and assets 5. FACTORS INFLUENCING MANAGEMENT (Positive and negative) What are the decisions? 6. OPERATIONAL OBJECTIVES How are they to be implemented? 7. PROJECTS/PROGRAMMES OPERATIONS AND TASKS By what means are they to be commenced? 8. IMPLEMENTATION WORKING PLANS, ORGANISATION, BUDGET Is it appropriate/effective? 9. MONITORING - EVALUATION ANNUAL SUMMARY OF TASKS CARRIED OUT AND OBJECTIVES ACHIEVED. REVISION OF THE PLAN modified from Perennou et al.294

events (fires, etc.) which have taken place there. Examination of the land register or archives may reveal details of changes in uses and modes of management at a site through a change of owner or of legal status. Photographic information: Dated aerial (or land-based) photographs may give valuable information about changes that have affected the site and its zone of influence (catchment area). Aerial photographs are, for example, very useful for studying changes in land use, the advance or retreat of a woodland or urbanisation. Aerial photographs are available for the whole of France dating back to 1950, in black and white and more recently in colour, for example from the IGN (www.ign.fr) or the Inventaire Forestier National (www.ifn.fr). Land-based photographs, if their location is precisely known, may provide valuable information about the general structure of the vegetation or about land use. Oral accounts: an inquiry (written or oral questionnaire) among site users or nearby residents will provide information about current perceptions of the site (values) and about past and present uses. These accounts may for example allow the date of cessation of certain practices (stock rearing, etc.), or the establishment of others (large-scale agriculture, etc.), to be established. This type of information should, however, be treated with caution and checked against other sources. Ecological appraisal This phase entails the defining of initial conditions (or “zero” position) of the site, by: • compiling a list of animal and plant species present at the site (and in some cases also in the zone of influence) ideally by mapping them (example: Fig. 29), • identifying and describing the key environmental variables involved in the functioning of the site, including the zone of influence, • identifying current and future threats (especially but not exclusively anthropogenic).

3. Site evaluation Along a stream, the zone of influence may be very long (the whole area upstream of a given point) and more or less wide depending on the catchment area. In addition, in the very middle of the stream the upstream-downstream connectivity* is very strong, with redistribution of sediments and of propagules* (eggs, seeds etc.) by the current during floods.

This evaluation prioritises the importance of the species/habitats present at a site by means of reference lists: lists of protected species (at the global, european, national or regional level), Red Books (at the same levels), Annexes to the Habitat Directives118, etc. Species appearing on the Global Red List (www.redlist.org), or in Annexe II of the Habitats Directive, are a priori of major interest

2. The descriptive approach This involves both the examination of existing data and the acquisition of new data.

Written records: Some sites have been the subject of research work or assessments that have given rise to publications, some of which may be old (for example the Grammont pool, Hérault, France). Unpublished data (reports, student dissertations, accounts of field trips, etc.) may also be very rich in detailed information and may be sought from universities and scientific societies. Newspaper articles may provide information concerning the site, its uses, or

72

Moreno P.

Collection of existing data Based on searches of the literature and of personal accounts, this preliminary phase enables the definition not only of current conditions but possibly also pre-existing, “reference” conditions. Various sources may be used:

Marsilea strigosa, a flagship species of temporary pools (annexes I of the Berne Convention, II and IV of the Habitats Directive)

5. Management and restoration methods

Figure 29. Example of the presentation of information on the natural-heritage value of a site (extract from the management plan for

Notre-Dame de l’Agenouillade, Fuselier152)

Grazing

General Presentation of the NotreDame de l’Agenouillade Life Site Former vineyards

Site boundary Site entrances

EU Habitats Directive habitats Mediterranean temporary pools*

Chem in de

Mediterranean swards with Brachypodium retusum** *Priority habitat – Natura 2000 Code: 3170 - ** Remarkable habitat

Vegetation types Copses with Elm dominant Mixed copses: Buckthorn, Azerole, Ash, Elm, Tamarisk Giant Reed Dry calcicole swards Mediterranean humid grasslands Pond vegetation community Abandoned farmland Plant communities of ruderal areas

Natural heritage flora Damasonium polyspernum Lythrum tribacteatum

Natural heritage fauna Bufo calamita* Hyla meridionalis* Triturus marmoratus* Triturus helveticus* Myotis myotis** *eggs, larvae and juveniles ** indices of major presence for these species

Car park

Notr e-Da me à Sain t-M artin

Residential area

Physical planning

Former military buildings Ruins Urbanised areas Former mini golf course Main paths Wells Restaurant “Le Lapin de Baluffe” Water purification station Roads

0

10

20 100 m

Impasse des Prun ettes

Residential area

40 m 2

Main threats

Fly tip Invasive species Senecio inaequidens Pools colonised by woody species Pools colonised by tall helophytes

Mapping 2001: J. Fuselier (ADENA) Field surveys: 2001 (J. Fuselier) – 2000 (O. Houles)

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Mediterranean temporary pools

Table 15. Plants of natural-heritage value present in the Roque-Haute Nature Reserve

I. HABITATS Mediterranean temporary pools (code 3170) II. SPECIES Adonis annua Aristolochia clusii Bufonia tenuifolia Bupleurum semicompositum Chenopodium urbicum Crassula vaillanti Damasonium polyspermum • Elatine macropoda Gagea granatelli • Heliotropium supinum Isoëtes duriaei Isoëtes setacea Kickxia commutata Lotus conimbricensis Lythrum borysthenicum Lythrum thymifolia • Lythrum tribracteatum Marsilea strigosa Mentha cervina Myosotis sicula Nonea echioides Ophioglossum azoricum Orobanche laevis Picris pauciflora Pilularia minuta Polygonum romanum ssp. gallicum • Pulicaria sicula Pulicaria vulgaris Ranunculus lateriflorus Ranunculus ophioglossifolius Romulea columnae Romulea ramiflora Taeniatherum caput-medusae Tamarix africana • Trifolium ornithopodioides Valerianella microcarpa Velezia rigida Veronica acinifolia

EUROPEAN Ber HD Ann. I Prior.

Pr

REGIONAL

T2 x T2 x T2 T2

x

T2

x

x x x x x x

x

x

x x x

T2 V T2 T2

x x

V V V V x

x x x

T2 V T2 T2 V T2 T2 T2 V T2

x

T2 T2 T2

x

x

x

x x

x

compared with a species that is rare or protected simply at the local level (example, Tab. 15). The evaluation will also be able to draw on the expertise of recognised specialists, particularly for groups that are poorly represented on the lists (insects and crustaceans for example). For example, at the Roque-Haute Nature Reserve (Tab. 15), two species of plants, as well as the “Mediterranean Temporary Pools” habitat (Annexe I Priority of the Habitats Directive), are of European importance. Thirteen species are of national interest (national protection and/or Red Data Book), with 16 additional species proposed for Volume 2 of the Red Data Book. A further 12 species are of regional interest. It should be noted that there are no lists for use in evaluating the interest of habitats at a national or regional level. The identification of Habitat 3170 in France may be facilitated by the use of the Habitat Registers158 which give details of the subcategories of each habitat, their characteristic suites of plants (enabling them to be identified), and their ecological requirements (see also Box 8, Chapter 2a).

74

NATIONAL RDB

x T2 T2 T2

Green: protected temporary-pool species Other species: protected species of habitats other than temporary pools • species formerly included but whose current presence is considered to be doubtful Status: Ber = Berne Convention HD = Habitats Directive National: Pr = Officially protected status x = protected RDB = National Red Data Book T 2: candidate species for volume 2 of the Red data Book V = Vulnerable Regional: Officially protected status x = protected

4. Directions (or long-term objectives) The presence of the “Mediterranean Temporary Pools” habitat, and of species with high natural heritage status, will often justify including their conservation in the long-term objectives of the management plan. More generally, the conservation or restoration of optimal hydrological and/or ecological regimes at a site will generally determine the directions of management. Examination of the assets and constraints associated with the site is necessary before long-term management objectives can be defined.

5. Factors which may influence management (assets and constraints) and their indicators The descriptive phase (cf. § 2. above) has allowed the factors to be identified, within or outside the site, that have or may have an effect on its functioning or its natural heritage value. The present stage has the aim of drawing up a systematic list of these factors and of evaluating the magnitude (current or potential) of their effects. The potential causes of dysfunction at a pool are very numerous and it is not possible to list them all (see Chapter 4). However, a

5. Management and restoration methods

systematic evaluation of the significance of the most common disruptive factors is necessary. This may be carried out by use of impact indicators which assess the status of populations and communities, and indicators of the functioning of the physical environment which will often provide information regarding the causes and mechanisms of the dysfunction. Impact indicators Dysfunction of a temporary pool may be suspected when: • the population size of one or a number of species (animal or plant) is decreasing, • communities or characteristic species are disappearing and/or being replaced by others (spread of tall helophytes* and trees, increase in algae, etc.), • species typical of different ecological conditions coexist with the characteristic temporary-pool species. The hypothesis of dysfunction may derive from a historical study which establishes that conditions have changed over time, and/ or from a comparison with similar habitats (richness in species or in groups of species, abundance of particular species, etc.). It is imperative that this analysis takes into account normal population fluctuations, especially those resulting from weather conditions. Interpretation of the data will be facilitated by use of references: previous data from the same site and under the same climatic conditions, or observations from other relevant sites (fluctuations are not necessarily synchronous between sites). Comparison between the current conditions and old data must be carried out with caution and must take into account any possible differences in methods and objectives.

pH or primary production (effects), or by indicator species: for example the proliferation of certain species of algae or of helophytes to the detriment of plants typical of oligotrophic* conditions, or the disappearance of animal species which are sensitive to the oxygen content of the water (certain insects, etc.). Inputs of toxic substances (herbicides, insecticides or accidental pollution) will often be more difficult to establish. Even though some species (bryophytes* and invertebrates for example) are recognised as being accumulators of some substances, their quantification remains difficult. When the hypothesis of toxic pollution is being considered, it is vital to consult experts to obtain verification. Sedimentation and erosion are natural processes, whose rate varies in relation to the type of substrate, the slope and the condition of the vegetation (Chapter 4). The rate of sedimentation may increase when the vegetation cover in the catchment area decreases (clearing, fire, erosion due to human activity, etc.). The hydrological regime and the animal and plant communities will be progressively affected. More competitive, less water-demanding plants will become established. Monitoring the depth of the water and/or the depth of the sediment may help with the diagnosis. Organic sedimentation is often less significant than the mineral component due to the low productivity of the pools which results from their nutrient*-poor status and from limiting hydrological conditions. However, this organic element may become predominant when inputs of litter from the catchment area are large or when productive species establish themselves in the pool (woody plants, helophytes) (see Chapters 4 and 5c).

The decline of one species may be linked not only with the disappearance of its habitat but also with other factors such as the appearance of a new predator or problems of reproduction (seed or egg predation, infertility, inbreeding, etc.), which do not necessarily have any connection with the habitat. The assessment of a species may therefore lead to more thorough studies of its biology.

Functional indicators The number of potential indicators is very high when the wide range of causes of the degradation of ecosystems are considered. While some indicators are applicable to many cases (water level for example), the search for indicators that are best suited to a local situation will take place through a functional analysis orientated towards the most probable causes of ecological change. For example, the hydrological regime may suddenly be disrupted by human activities (drainage, siltation of a pool, continuous artificial supply of water, etc.): the ecological changes will then be immediate and the causes easy to establish visually. When the hydrological modifications are less severe, such as reduction or prolongation of the flooding period (due to pumping, climatic change, modifications in the zone of influence, etc.) it will only be possible to reveal them through long-term monitoring. The effect of an input of nutrients (eutrophication) will be identified by measurements of nutrients (cause), or of dissolved oxygen,

Pozzo di Borgo, M.-L. (OEC)

When dysfunction has been confirmed or seems probable, its causes must be investigated. Hypotheses, generally many at first, are generated. In the case of a temporary pool, disruptions of the “classic” key factors involved in its functioning are looked for: hydrological regime, water quality (eutrophication or pollution), sedimentation, closing-up of the habitat (cf. Chapter 4).

In summer, the use of the Chevanu pool (southern Corsica) as a car park causes compaction and ruts which are visible during the flooded phase

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Mediterranean temporary pools

Usage indicators Changes of use bring with them modifications of the ecosystems which affect the physical environment as well as the populations (Chapter 4). These changes of use need to be identified using simple indicators such as, for example: • cessation of grazing (indicated by closing-up of the habitat, indicator species, the characteristic shapes of browsed shrubs, low walls, etc.), • cultivation of pools or their surroundings (ploughing, low walls, drains, etc.), • digging (extraction of material, shape of the pool, slopes, etc.), • dumping of various materials, • use for parking (soil compaction, destruction of vegetation, ruts, etc.).

6. Operational objectives

A very wide range of management operations can be implemented, in response to the diversity of ecosystems and of threats. These may involve, for example, simple surveillance of the condition of key ecological characteristics of the site (notably hydrology), detailed ecological management or even restoration of the pools, actions affecting the catchment area, awareness raising among site users, environmental education, specific activities involving a species, and/or the acquisition of the site or setting up a management contract. Two particular examples are given here: • The restoration of pools The highest priority of the management objectives will be to control or correct unfavourable ecological changes. The operations will consist of eliminating the causes of degradation (siltation or pollution, for example) and then re-establishing favourable conditions for the characteristic Mediterranean temporary-pool species. Actions involving the water, the soil, the vegetation, and the provision of information to site users will often be required, and they will be accompanied, if necessary, by the re-introduction or reinforcement of populations of the species. • Creation This involves, in this case, the construction of a functioning site where none currently exists. The creation of a Mediterranean temporary pool requires a thorough initial study of the ecological functioning of the site33, 215, 411, 419. It is essential that some of the physical characteristics (substrate, hydrology, etc.) are suitable, while others increase the chances of success of the habitat creation (proximity of other temporary pools, etc.) (“Assets and constraints” paragraph, this Chapter).

Grillas P.

The operational objectives of the management of Mediterranean temporary pools will be the site-specific application of the directions (§ 4 above), once the constraints and assets have been taken into account (§ 5). Some objectives will be centred on biodiversity conservation issues (particular species or communities, physical characteristics, etc.), others on activities and uses at the pool or in the surrounding area (grazing, crop growing, forest, built-up areas, etc.), and still others on the integration of the site within the social sphere. For example, the Valliguières161 management plan sets out, among others, the following objectives: • to augment the size and viability of the Great Crested Newt population by improving its breeding success and its adult survival, • to improve the potential of the site as reptile habitat, • to involve the local commune and its residents in activities related to the management and understanding of the site.

7/8. Operations

Studying the seed bank (core sampling of the sediment), a tool in the restoration feasibility study (Péguière pool, Var, France)

76

5. Management and restoration methods

Outside a management plan: brief or detailed assessment? In some cases a site assessment is necessary without being included, at least in the first stage, in a management plan (for example, appraisal in the framework of contractual management such as Natura 2000). This assessment may be more or less thorough depending on the particular case. Brief assessment, based on ecological inventories, enables any possible dysfunction to be identified with the aid of comparisons (bibliographies or reference sites), and hypotheses regarding their causes to be generated. This rapid assessment corresponds to phases 1 to 3 and 5 of the management plan. The individual carrying it out must have a thorough understanding of the ecology of this type of ecosystem (temporary pools or streams), and preferably of the site itself. External experts may be consulted regarding topics requiring more highly specialised knowledge, relating to species (for example the identification of certain groups, population biology) or to complex processes (hydrology, hydrogeology, etc.). As well as this basic knowledge, an expert will be familiar with examples with which comparisons may be made, allowing dysfunctions to be identified. Detailed assessment furthers the analysis by focusing it on the results of the brief assessment. It is the combination of “Initial assessment” + “Detailed assessment” that generates the hypotheses which form the basis for decisions regarding management measures and monitoring (see Chapter 6 and Tomas-Vives388). Detailed assessment is in general undertaken in the two following cases: • validation (or refutation) of the hypotheses formulated regarding the previously identified ecological changes, • evaluation of the resilience of the ecosystem, i.e. its capacity to return to normal functioning when the cause(s) of the dysfunction have been corrected. The study will seek to examine for example the possibilities for the restoration of populations in the absence of direct intervention (introduction, population reinforcement). Most successful assessments, leading to effective management measures and to appropriate monitoring, are based from the outset on accurate recording of the species present and of environmental factors.

Box 41. A detailed assessment: the Péguière pool (Plaine

des Maures, Var) The Péguière pool site was well known until only about ten years ago for its flora, characteristic of a low-elevation Isoetion formation (Médail, pers. com.), with species such as Ranunculus revelieri. At present there are a number of indications of infilling: • no open water phase (surface water), • very deep soil, • vegetation typical of temporary pools no longer appears except in a fragmented way, in small depressions. Botanical surveys (quadrat transects) currently reveal a commonplace grassland flora with Paspalum dilatatum, Anthoxanthum odoratum, Festuca gr. ovina, Holcus lanatus, Avena barbata, etc. A study of the topography and the hydrological regime has shown that water levels are determined by the groundwater, which follows the (non-horizontal) profile of the underlying rocky substrate. The probable cause of the infilling of the pool is strong erosion within its catchment area, which is exacerbated by the degradation of the vegetation by fire and the repeated passage and parking of vehicles (cars, motorcycles). Now that the catchment area has been protected from vehicle traffic the vegetation should rapidly recolonise and the rate of erosion should slow down. Restoration (dredging) of the pool may therefore be envisaged. Since the current vegetation (zero state) is very poor, it seemed advisable to evaluate the potential of the seedbank for restoring the former floristic richness of the site. Regular core sampling of the soil was therefore carried out over the whole surface of the pool. These core samples were then divided into four depth layers (each 2.5 cm) to locate any viable seed stocks. Germination tests on the soil samples revealed low levels of seeds for the species being looked for (the Isoetion). The restoration of the flora of the site cannot therefore be based on its own seedbank. It will have to rely on spontaneous recolonisation from nearby sites (the network of rivulets in the catchment area) or on reintroduction of seed. Gauthier P. & P. Grillas

Box 40. A brief assessment: the Rodié pool (Plaine des

Maures, Var) It was at this flagship pool in the Plaine des Maures that the Rodié Buttercup (Ranunculus revelieri subsp rodiei) was discovered and described for the first time. At present, rapid assessment based on the distribution of the vegetation leads to the hypothesis that rushes (Juncus conglomeratus) are invading the pool. The rapid assessment does not permit the verification of this hypothesis of ecological change. A likely cause is the alteration of the hydrological regime following widening of the road which has encroached upon the site. In order to test the hypothesis and to evaluate the possible impact of the spread of rushes on the Rodié Buttercup it was

decided to survey the site. This involves a number of aspects: Detailed mapping of the rushes and the vegetation was carried out at the time of maximum water level. The area occupied by the Rodié Buttercup and by other plant species is regularly surveyed using fixed quadrat transects. In addition, the buttercup is accurately counted in each quadrat. The surface water level (hydrological monitoring) is regularly recorded from a fixed scale in the centre of the pool. The existence of a detailed topographic study, previously carried out, allows the duration of flooding at different parts of the pool to be deduced from this water level at a single fixed point. Gauthier P. & P. Grillas

77

Mediterranean temporary pools

b. Land management and uses Perennou C. In most of the countries of the Mediterranean Basin, the State or regional authorities are able to restrict the uses to which private land is put, within the framework of statutory protective measures. However, it is not possible to compel an owner to manage the land for nature protection who does not wish to do so. Hence, the control of land uses by public or private nature protection bodies may be essential for the management of temporary pools. Such control may be either complete (through acquisition) or partial (by contract, lease, or agreement with the owner). Acquisition, or even partial control over the land, is not a precondition which needs to be applied in every case. Less restrictive and less costly means will be preferable whenever they are possible. The incidence of resorting to acquisition or contractual management for the conservation of natural habitats is very variable depending on region and country. In some there are private or public organisations with their own resources and with experience in these methods of control. However, in many countries experience is non-existent or only recently acquired. In addition, information is very scattered and little published, and almost never specifically relates to Mediterranean temporary pools. Summaries are rare, with the exception of those carried out in the Mediterranean countries of the EU within the framework of the LIFE “Green Register” for coastal habitats44 (www.green-register.org). The following is therefore based mainly on information relating to a wider range of natural habitats (Natura 2000 sites, coastal sector, etc.). This information is, however, very likely to be relevant to the pools. Outside the EU information is practically nonexistent, and it appears to be practically impossible to implement actions to influence land and use management, particularly if, as is very often the case, the landowner is unknown. Superimposed traditional rights and nationalisations/denationalisations may create a legal tangle which is difficult to unravel (Bougeant, pers. com.). Within the EU, the European Commission deems the acquisition of land of high biological value within the framework of LIFE projects to be acceptable only to the extent that it enables active management, necessary for the protection of key species or habitats, to be carried out. For areas of land considered to be already protected through their inclusion in the Natura 2000 network, acquisition through LIFE cannot be seen as a means of countering threats, which in this situation are the sole responsibility of the member States. Temporary pools constitute a habitat well suited to the philosophy of Natura 2000, which advocates that management be carried out by contract as much as possible: these habitats have for a long time depended on traditional human activities which are currently in decline (stock grazing); their restoration often takes place through the maintenance or restoration of these activities, by agreement with those who carry them out or by adapting them (DFCI, for example) to improve their compatibility with conservation.

a. Depending on the region, these may be either association-based or dependent on the local authority. b. Such as the Service des Domaines in France, the Comisiones Provinciales de Urbanismo in Spain, and similar bodies in Italy and Portugal.

78

Land acquisition Acquisition is the mode of control offering the greatest longterm security. It may be achieved by a public organisation: • in France: Conservatoire du Littoral, départements, • in Portugal, following the purchase by the State of the land forming the current Paul de Boquilobo Nature Reserve in the 1970s, the Istituto de Conservaçao da Natureza has recently begun to acquire land within the protected areas which it manages, • in Spain, the government of the Balearic Autonomous Community (8000 ha acquired) has a wide experience of acquiring land for nature, • in Italy, no public authority has acquired land for conservation to date, but some regions are beginning to take an interest, • in Greece, the State is acquiring land in the Central Zones of the National Parks20 but information is lacking as to the areas acquired up to now. The same procedure is envisaged there within the framework of Natura 200020 and, more widely, for natural coastal areas close to tourist zones44. Acquisition may also be achieved by a private interest: • foundations: Fondation Sansouire in France (many temporary pools in the Camargue), Fundacio Territori i Paisatge in Catalonia (FUNDTIP; 7000 ha acquired in 2 years of activity), Fondation Global Nature in Spain (www.fundacionglobalnature.org/), etc. • organisations: WWF Italy (many “oases”), Conservatoire Régional des Sitesa in France, GOB and SEO/BirdLIFE in Spain (540 ha bought by the SEO in the Belchite steppes and the Ebro Delta, within the framework of European ACNAT/ LIFE projects) (www.seo.org), Nature Protection League in Portugal (purchase of land of ornithological value in the south of the country, Castro Verde, within the framework of two LIFE projects), etc. In most references it is not stated whether or not the acquired land contains temporary pools. As organisations that are more administratively flexible, but which often have access to fewer funds compared with public bodies, they are more vulnerable to the financial hazards of a project: delays in payments by providers of funding, greater difficulty in obtaining loans. Acquisition is facilitated when specific organisations exist for which it is one of the main aims, if not the only aim: specific resources allocated, financial skills and contacts, legal arrangements facilitating their involvement (pre-emptive right, price-regulating bodiesb, possibility of compulsory purchase, inalienability of the acquired land, etc.). Spanish regions have often abandoned projects due to their administrative complexities. Inalienability provides one of the best guarantees for the protection of sites in the very long term: once acquired, there is no risk of resale. This is the norm in France for Conservatoire du Littoral land and in Spain for that belonging to FUNDTIP. Compulsory purchase is an expensive method (legal procedures) to be used selectively and useful mainly as a tool in negotiations. The right of compulsory purchase exists in all the Mediterranean EU countries but to different degrees: strong and widely used in France, weak in Italy and Spain, limited to a narrow coastal strip in Portugal, and not used for conservation purposes in Greece. The study carried out within the framework of the Green Register44 concluded that the principal legal tools permitting the

5. Management and restoration methods

to encourage private owners to feel responsible, (see for example Pietx298) and are especially suited to the “Natura 2000 philosophy”. It should also be noted that at a given site they may be used in a complementary way alongside land acquisition, as has been the case at a number of LIFE sites (Fig. 30), in the regulation of the catchment areas as well as of the pools themselves.

acquisition of land are well established in the Mediterranean countries of the EU but little used for conservation purposes. Acquisition may appear expensive in absolute terms: in the context of the LIFE “Temporary pools” project, approximately 2500 to 4000 €/ha have been set aside for purchases carried out in 20022004 in southern France. However, the balance sheet for acquisitions in France by the Conservatoire du Littoral shows that the total amounts are small in comparison with investments in other spheres44.

In France, the Conservatoires Régionaux d’Espaces Naturels regularly employ this mode of site regulation. They currently manage over 35,000 ha of natural habitats through contracts with hundreds of farmers and communes131.

These methods allow the use of the land to be partly regulated without acquisition and hence at lower cost. They may also be used, if the manager is also the owner, to delegate a proportion of the management activities (in particular grazing).

In Slovenia, a LIFE Nature project in the Karst Edge (Kraski rob), situated in the sub-Mediterranean part of the country, provides for the restoration of four pools followed by their management based on contracts with the official managers/owners, with the aim of conserving their biological value (Sovinç & Lipej, pers. com.).

Contracts and agreements may be very variable in type and duration even within a single country (see Lévy-Bruhl & Coquillard234 for France, for example). The ease with which they may be implemented for the conservation of natural habitats is probably variable from country to country, but no summary exists. These modes of management fall within the framework of an increasing tendency

In Spain, since 1999, about twenty NGOs (mainly in Catalonia and the Balearics) have set up activities of this type on behalf of natural habitats, and a guide to these practices has been published in Catalan (Pietx, pers. com.). The Fondation Global Nature, for example, has created, by means of agreements with the owners, a network of 49 private Biological Reserves, amounting to almost

Use management by contract/agreement

Figure 30. Land evaluation of the Etang de Valliguières Natura 2000 site

2

3 6

7

8

4

5

9

10

11

12 13

19

14 15 16

20 18

17

27

21 26

28 29

58

22

25

work of the Life “Mediterranean Temporary Pools” project

■ Land parcels subject to a land management agreement ■ ■ ■ ■

between the CEN-LR and the commune of Valliguières (and the ONF for land parcel 70) Land parcels subject to a land management agreement between the CEN-LR and an individual Temporary pools Perimeter of Natura 2000 area Catchment area of the wetland

30

31

■ Land parcels acquired by the CEN-LR within the frame24

32 23

Map: Conservatoire des Espaces Naturels du Languedoc-Roussillon

70

33

50 m

79

Mediterranean temporary pools

4000 ha, for the protection of the Spur-thighed Tortoise Testudo graeca in Andalusia and in the Murcia Region (www.fundacionglobalnature.org/). Such networks could also be created for other species or habitats such as temporary pools. SEO/BirdLIFE (www.seo.org) manages eight reserves (over 1000 ha), mainly comprising ornithologically valuable habitats, by agreement with private or municipal owners. In the Guadalquivir Delta, a private estate which forms an enclave within the Doñana National Park (the “Finca de los Gonzalez-Byass”) contains some temporary pools. Its management is subject to management guidelines from the National Park, by agreement with the owners (Serrano, pers. com.). The Autonomous Community of Valencia has created an innovative system of “floristic micro-reserves”217, which is a hybrid system of contractualisation and strong, compensation-based legal protection. A micro-reserve (always <20 ha) depends on the voluntary acceptance of management constraints as prescribed in a contract agreed with the regional authorities. It may only be revoked by the owner if the compensation received is repaid with interest. The owner receives compensation in one single payment of up to 1800 €/ha in the case of wetlands (maximum of 6010 €/ site for private or municipal owners, 18,030 €/site in the case of an NGO, Foundation or University). An extra premium of 50% may be paid if the sites contain plants which are strictly protected by the Habitats Directive. In early 2003, of the 150 microreserves created in this way in Valencia, three have temporary pools (Tab. 16). In view of its success, this formula has also been proposed for use in the Castilla-La Mancha and Andalusia regions (Reques, pers. com.). In Andalusia, a similar mixed system (contractual-statutory) was set up by the Law 2/89 of 18 July 1989. It provides the possibility of creating “Partnership” Nature Reserves for sites with high natural value, in particular on private land. It does not yet appear to have been used to protect temporary pools. In 2002, the Spanish government opened a credit line enabling such contracts to be agreed for the management of Natura 2000 sites (Pietx, pers. com.). In Portugal, cases are very rare. An agri-environmental contract (not yet approved) has been proposed for one site with temporary pools (Alcazar, pers. com.). In the Vale do Guadiana Natural Park, contracts have been agreed between the Park’s management body (ICN) and some landowners in respect of measures to support the birdlife. Such measures have not been considered necessary for the conservation of the temporary pools in the Park due to

Table 16. Micro-reserves in Valencia containing temporary pools

Micro-reserve

Owner

Area

Lavajo de Arriba

Sinarcas Council

0.5 ha

Lavajo de Abajo

idem

0.7 ha

Balsa de la Dehesa

Soneja Council

10.5 ha (ca. 3 ha of wetland, 7.5 ha of Cork Oak forest and matorral)

80

their small area, easily excluded from cultivation (Cardoso, com. pers.). In Morocco, the Sidi Bou Ghaba Ramsar site contains a fringe of temporary marshes. Classified as a forestry estate, it is, in this capacity, the property of the State and is managed by the Ministry of Agriculture, Rural Development, Water and Forestry. The Society for the Protection of Animals and Nature (SPANA), a Moroccan NGO directed to the public benefit, has been managing the whole site for several years on the basis of an agreement with the Department. SPANA carries out surveys and conservation of the flora and fauna, deals with visitors and manages the education centre. This management is carried out in collaboration with all the parties involved in the conservation of the environment within the framework of a local committee (Bouchafra, pers. com.). This example of contractual land management by a conservation NGO is remarkable, and may be the only case among the countries of the southern Mediterranean.

Summary of these methods of regulation In Greece, land acquisition and leasing contracts for the protection of habitats still do not take place (Dimitriou, pers. com.) except in the central zones of National Parks. In Portugal, these modes of involvement are still very little used (Alcazar, pers. com.) despite some recent achievements by NGOs and State bodies (ICN). In Spain, acquisitions have especially involved sites of ornithological value (and hence not temporary pools a priori); there are several cases of part-contractual, part-statutory management at the micro-reserves of Valencia. In France, a range of temporary pools are at least partly under land management, both by the State (Conservatoire du Littoral) and by NGOs: Valliguières, Redon, Plaine des Maures, pools at Lanau, the Tour du Valat and Vendres, etc. In total, more than 2000 ha of land where pools occur are protected in this way. In addition, management agreements have been set up with owners or managers at two sites at least (as at 1/10/2003), in the framework of the LIFE “Temporary Pools” project. Complementary contractual measures are likely to be put forward within the framework of the implementation of Natura 2000 contracts at further important temporary pool sites. In Turkey, these modes of protection/management of land do not appear to be used, either by the State or by NGOs (Bulus, com. pers.), while in Morocco an experiment in management by agreement, albeit not involving pools, is in progress.

5. Management and restoration methods

Box 42. Land acquisition: the lessons of the LIFE

“Temporary Pools” project for France The management of land or usage is often very time-consuming, all the stages listed below being potentially subject to delays, as the LIFE “Temporary Pools” project has shown: • identification and location of landowners, not always possible within the project deadlines, • preliminary contacts with landowners who are not very conservation-minded, • negotiations, sometimes complicated due to land being in joint ownership, the reversals of landowners, rapid changes in the local property market, • various administrative delays: deliberations of the public buyer, obtaining bank loans, etc In the context of the LIFE “Temporary Pools” project, delays of three or four years between the initial contact (project set-up phase) and the signing of the purchase agreement have been experienced. Interruptions of the process at the conclusion of the phases of location of, and initial contact with, the owner, also occur for various reasons: • change of mind on the part of the owner (or of one or more owners in the case of joint ownership) so that they no longer wish to sell or lease their land, • sale to another private purchaser (via a faster decision) or the acceptance of a higher purchase price. In the framework of a short-term project (4-5 years) of the LIFE type, some pernicious effects may be seen towards the end of the projects. The sellers increase their selling price knowing that the purchasers have little available time before they forfeit their LIFE funding. If the asking price rises above the limit acceptable to the providers of the funds, anticipated purchases will have to be abandoned. In total, of five sites initially earmarked for acquisition, only two were purchased, as well as a third which was not initially identified but where an opportunity arose. Furthemore, at one of these sites, a proportion of the purchases have been replaced by management agreements judged to be adequate in view of the management issues. Perennou C.

c. Management of habitats and species Gauthier P. & P. Grillas

Introduction The management/restoration or creation of temporary pools must be preceded by a detailed site assessment (Chapter 5a). This precondition allows potentially deleterious activities to be minimised. Sometimes, in the absence of information enabling hypotheses regarding the changes taking place to be confirmed, decisions may be based purely on these hypotheses. An understanding of similar situations and sites is therefore essential. In all cases an evaluation of management is necessary (Chapter 6), in order possibly to question the hypotheses and/or to adapt management activities (“Adaptive management”).

Whether the project relates to management/conservation, restoration or creation of a temporary pool, it is crucial that an unstable hydrological regime is maintained (or restored/created); the irregularity is a key factor in the functioning of this habitat and of its species. Before any restoration activity takes place, it is necessary: • to ensure that the causes of observed negative changes have been removed (or may easily be removed), • to evaluate the feasibility, the cost in terms of man-hours, the financial costs and the probability of success, • to assess the impact of the operations on the functioning of the ecosystem as a whole: operations aiming to favour one species or a group of species may be unfavourable to others or detrimental to some human activities (costs and benefits of the operation), • to evaluate the extent of the operation: when natural hydrological conditions have been re-established, should the species be allowed to recolonise the site naturally? Or should all or part of the range of species whose return is desired be re-established artificially?419

Box 43. General recommendations for the restoration of

wetlands Zedler419 sets out ten basic principles for the restoration of wetlands: • The location of the site is decisive: the conditions regarding geology, water etc. must be favourable. • Natural sites must be used for comparison. • The hydrological regime (instability in the case of temporary pools and streams) is a crucial factor in the restoration of the biodiversity and functioning of a wetland. • The various components of the ecosystem (nutrients*, organic material, sedimentation, vegetation, fauna, etc.) develop at different rates. • The accumulation of nutrients (P, N) in the sediments may slow the rate at which biodiversity redevelops. • Some types of perturbation (felling, grazing etc.) may augment species richness. • The existence of a seedbank and/or of dispersal processes may facilitate the restoration of a diverse plant cover. • The environmental conditions and the biological characteristics of the species must be considered when the restoration of the biodiversity of a site is desired. It may be pointless to reintroduce species which will colonise naturally when the ecological conditions become favourable267, while Nature must be helped in the case of some sensitive species or when natural repopulation is improbable402 (absence of a seedbank or source population). • Predicting the restoration of a wetland depends on the theory of succession, the vegetation at a given site being in a state of continuous change. • The existence of genetic differences within a species (ecotypes) may influence the results of a restoration project: the introduction of populations which are poorly adapted to the ecological conditions at a site may end in failure (disappearance, etc.). Based on Zedler419

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Mediterranean temporary pools

The principal habitat management operations at temporary wetlands The choice of management operations is determined in the first place in relation to their appropriateness regarding the existing problem and the processes at work (Tab. 17). For each of these operations, evaluations of the technical feasibility and of the costs involved are very important factors to be taken into account before operations can begin.

Box 44. Management of a temporary pool following

burning: the example of the Catchéou pool (Var) During the summer of 2003, the Massif and Plaine des Maures were severely affected by fire, with 1960 ha burnt. The areas of the massif with cupular pools, and the parts of the plain with depressions and temporary streams, fell within the area of devastation. In the Plaine de Palayson, the famous Catchéou pool was burnt, as well as several temporary streams. Following the disappearance of the vegetation cover, it was feared that increased sedimentation and severe eutrophication would take place, due to the erosion of the catchment area (sand-rich substrate). Fire therefore constitutes a double threat, acting directly on populations (amphibians, reptiles, etc.) which cannot escape it, and indirectly through terrestrialisation which may modify the hydrological regime of the pool and so indirectly disrupt its animal and plant communities (decrease in the duration of flooding). Burial of seedlings also poses the risk of germination failure for some plants. Given the very high natural heritage value of the site, the Office National des Forêts decided on preventative intervention. Ecological engineering operations have therefore been carried out by the ONF, in partnership with the CEEP. These actions, based on the techniques of the Restauration des Terrains en Montagne (Restoration of Mountainous Land) type, are tailored to the problem and to the size of the pool, with a view to minimising erosion and the deposition of sediment. The management works consisted of: • placing fascines in semicircles in two rows all around the pool. These fascines are made from branches of Tree Heath Erica arborea (unburnt), reinforced beneath by Giant Reed Arundo donax to give greater rigidity. Posts of 10-cm diameter ensure that these fascines are firmly fixed, and their bases are slightly buried in the ground. The purpose of the fascines is to limit the silting up of the pool by material brought down from the catchment area, in particular during the autumn rains, which are generally heavy. They should also limit the

82

Management operations carried out at LIFE “Temporary Pools” sites and at other temporary pool sites are described here by way of example. They should only be applied to other situations if the whole process, starting with an appraisal of the initial conditions and the management problems, is carried out from start to finish. Information which is incomplete or partly empirical does not permit the formulation of more general models for management or restoration. The implementation of a management operation is above all a local decision that depends on the available information (literature, surveys, comparisons etc.), on the characteristics of the site and on the available resources.

Sedimentation management Infilling forms part of the natural dynamics of pools but may be increased by various perturbations (Chapter 4, Box 44). It results from the accumulation of minerals derived from the catchment area and of organic material produced on the site or brought in from outside. The consequences of sedimentation are an increase in the depth of the sediment and its water content (and hence a decrease in the level of water stress in summer and heightened competitiveness of perennials), a decrease in the depth and duration

amount of ash being washed into the depression. They act as filters and allow water to pass through, • in the thalwegs of the catchment area, burnt scrub was cut out and the dead material removed, • the felling and removal of dead burnt trees within a radius of 50 m around the pool. Site monitoring is planned, including: • hydrological functioning (dates of flooding and drying, water levels), • measurement of the rate of sedimentation using graduated scales inserted into the bed of the pool, • monitoring the fauna (invertebrates and amphibians), • monitoring the flora, • photographic monitoring. Catard A. & L. Marsol

Marsol L.

When manipulation of species proves necessary, a number of problems may arise408: • legal: manipulation of protected species is subject to legislation, • technical: for most species, techniques for captive breeding (or breeding in vivo) and reintroduction into the wild are poorly developed, • genetic: the source populations for reintroduction will generally have to be from nearby sites, to minimise genetic contamination and to benefit from local adaptations. There will still, however, remain a risk of genetic bottlenecks* (low genetic diversity linked with low numbers).

After a fire, the protection of the Catchéou pool with fascines slows down the silting-up process (before the fire, see photo page 10)

5. Management and restoration methods

Table 17. Choice of management operations according to their appropriateness with regard to the existing problem and the processes in place Problems

Process

Infilling

Accumulation of sediment • reduction in hydroperiod

• burying of seeds

Objective

Management method

Remarks (faisability, etc.)

Cost

Restore a favourable hydrological regime

Digging: manual if small surface area (spade); mechanical if larger surface area (digger)

Prior determination of the depth of digging required, depending on previous regime, seedbanks, etc.

Depends on how far the sediments are removed from the site

Delicate operation: high risk of removing seed stocks with the litter and of damage to the existing vegetation

Low if surface area is small

Replace the seeds on the surface in conditions favourable to germination Restoration of the plant cover in the catchment area, limitation of frequentation

Direct modification of the hydrological regime

Indirect modification of the hydrological regime (interventions in the catchment area)

Accumulation of litter of internal or peripheral origin leading to: • burying of seeds

Remove litter

Superficial removal (manual)

Reduce internal or peripheral sources

Control of woody species and large helophytes

• eutrophication

Limit accumulation

Drainage

Restore a favourable hydrological regime

Sealing of drains, filling in

Permanent filling with water by direct supply (pipe, etc.)

Restore a favourable hydrological regime

Removal of the water supply

Diversion of runoff water, plantations on catchment area, removal of water from the water table

Restore a favourable hydrological regime

Restoration of the catchment area, Very variable legislation controlling removal of water from the water table

Shrub encroachment

Open up the habitat, limit intake of organic matter

Scrub clearing or cutting, with removal from the site of cut vegetation, grazing

Increase in large helophytes

Limit competition

Cutting and/or root stripping, with removal of cut and uprooted vegetation,

Very variable

Permanent filling with water through modification of the catchment area (dam…) or supply from the water table Competition/Light, Eutrophication

Limit intake of organic matter

The cause of the increase should be identified: Modification of the hydrological regime? Absence of grazing?

Grazing Root stripping runs a high risk of removing seed stocks from the site with the root mat and of damage to the existing vegetation

Increase in the density of small terrestrial or amphibious herbaceous plants

Limit competition

Vegetation clearing with removal of the cleared vegetation, Grazing

Invasive plant species

Limit competition Limit accumulation of organic matter

Arrachage manuel, pâturage Information, communication

The durability of action to limit invasion should be evaluated

Predation

Introduction of fauna (fish, crayfish, etc.)

Remove the predator

Elimination of fish fauna / return to an unstable hydrology Information, communication

Elimination of crayfish and certain invasive amphibians is not very likely as they have refuges outside the pools

Pollution

Direct dumping

Awareness raising, reduce risks

Information, communication with public and local authorities, government departments responsible for enforcing anti-pollution law

Indirect dumping (in catchment area)

Limit sources of pollution

Information, communication, contracts, etc.

Cleaning

Information, communication, etc.

Debris, dump Overgrazing, excessive trampling

Modification in the structure of the substrate, acceleration of erosive processes Deterioration in the plant cover Limitation of reproduction

Reduce the amount of grazing, modify grazing seasons, etc.

Information, communication, contracts, etc.

Colonisation of the catchment area by woody plants

Disturbance of amphibians in the terrestrial phase

Open up the habitat

Scrub clearing or cutting, with removal of cut vegetation, Grazing

Scrub clearing should be limited in order not to increase erosion and to maintain refuge areas, with potential shelters for amphibians

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Mediterranean temporary pools

Box 45. An example of restoration by digging: the Péguière pool, Var, France Siltation of the pool was diagnosed, caused by increased erosion in the catchment area, whose vegetation had been degraded by the passage of vehicles (Box 41, Chapter 5a). Acquisition by the Conservatoire du Littoral and management by the commune (Cannet-des-Maures) have enabled the traffic to be controlled: the vegetation should recover rapidly and the erosion should slow down. The assessment also concluded that it would be possible to restore the hydrological regime of the pool by digging, and there were no significant residual seed stocks capable of restoring the populations of temporary pool plants. A restoration project has therefore been devised, to proceed in several stages: • Assessing the water regime at the pool. • Carrying out the digging works. • Verifying the re-establishment of favourable hydrological conditions (possibly involving corrective works). • Monitoring the possible appearance of the desired species. • When the hydrological conditions are re-established and if the species do not colonise the habitat spontaneously, introduction by means of seed stocks derived from the closest sites (nearby streams).

A plan has been drawn up for taking off a top layer of sediment from the eastern part of the pool and removing it from the site (Fig. 31). The thickness to be removed was determined in such a way as to lower the surface of the soil down to the water table, as measured in May 2001, and to retain a thin layer of soil above the underlying rock. It was decided to carry out the removal close to the inlet point of a rivulet so as to facilitate filling with water, and over a limited proportion of the pool so as to reduce the costs of removing the sediment from the site and to verify whether the hydrological objectives are achieved (submersion for some weeks every year, at least during wet years). It will be possible to carry out corrective works if necessary. Since it is not necessary to retain any soil horizon to reseed the site, the removed sediments will be taken away, but will be dumped fairly close by so as to minimise transport costs. The gradients defined are shallow, so as to avoid erosion and to promote a wider range of conditions. The proposed area to be modified amounts to 530 m2 and the volume of sediment to be removed will be 115 m3. The cost of the operation is estimated as 3300 € of which about one-third is for the digging and the remainder for transporting the arisings. It is planned to carry out the works during the first few weeks of 2004. Grillas P., N. Yavercovski, E. Duborper & M. Pichaud

Outlet

B

B

A’

A’

Rivulet

A

A

B’ 0

B’

10 m

0

10 m

Rivulet (2) Relative altitude in m after silt removal

(1) Relative elevation in m of the initial state

0,8 0,4 0 ■

-0,4

■ ■ ■

-0,8

■

1 6 11 16 21 26 31 36 41 46 51 56 61 Distance in m

84

Transversal section BB’

Topo 1 Topo 2 groundwater bedrock

Relative elevation (m)

Relative elevation (m)

Longitudinal section AA’ 1,5 1 0,5 0 -0,5 -1

1

6

11

16 21 26 Distance in m

31

Map: M. Pichaud & A. Sandoz - Station biologique de la Tour du Valat

Figure 31. Restoration of the Péguières pool

5. Management and restoration methods

When the siltation is associated with an accumulation of mineral soil, correct hydrological functioning may be restored by digging out the pool and taking away the sediment. Depending on the size of the pool, this digging may be mechanical or manual. The main difficulties with restoration by removal of the upper layer of sediment are, firstly, deciding on the level to be dug down to (historical level or level to be calculated based on hydrological objectives), and secondly, the presence or otherwise of viable seed stocks. The digging must therefore be complemented by a cartographic study of the underlying substrate and an analysis of the various soil horizons, so as to locate any seed stocks and if possible to use them for restoring the vegetation.

Management of woody vegetation The colonisation by woody vegetation around and within temporary pools brings problems of shading (competition) and litter accumulation, and, as a result, difficulties for heliophilous* species as regards emergence and growth (Chapter 4). Opening up the habitat reduces light competition and the input of litter. Depending on the extent of the area to be cleared, cutting may be done manually (using shears) or mechanically (power saw, brushcutter). The maintenance of the cleared area must then be ensured, preferably using livestock, which will control both the woody species and also the most competitive herbaceous plants. Various livestock may be used, depending on the characteristics of the species which it is wished to control. For example goats, and to a lesser degree sheep, will be more effective than cattle or horses for controlling woody growth. Management by grazing should be subject to an agreement with the owner of the stock, in which may be included periods when no grazing takes place (sensitivity of some species at critical stages in their development), and the maximum grazing pressures per hectare (threshold for the risk of overgrazing). The effect of grazing may be measured for particular target species or, overall, for the richness or structure of communities or of the ecosystem.

Management of helophytes The spread of large helophytes (rushes, Scirpus, bulrushes etc.) in temporary pools may be linked to various causes such as an increase in the depth of the sediment, or an increase and/or stabilisation of the water level. These highly competitive species develop to the detriment of the characteristic temporary-pool species, which struggle to survive in their shade and in the increasingly eutrophic conditions resulting from the accumulation of their litter.

Box 46. Spread of woody plants in the pools at Roque-

Haute In the pools at the Roque-Haute Nature Reserve (Hérault) where no grazing has taken place for about fifty years, the spread of elm (Ulmus minor) and ash (Fraxinus angustifolia subsp oxycarpa) appears to be unfavourable to populations of Isoetes setacea328. This hypothesis was tested by means of an experimental clearing operation. One year after the woody growth was cut, the frequency of Isoetes had increased by 43% in the cleared zone compared with an increase of just 7% in the non-cleared zone (a “year” effect). In addition, in the cleared zone, a decline in litter caused the frequency of Isoetes to increase by a further 14%. A complementary experiment, in the laboratory, showed that reduction in light affects the biomass production and the production of spores in this species (Fig. 32). These results therefore suggest that interception of light by the woody species, or more generally by competitive species, is sufficient to explain the reduction in the small species characteristic of Mediterranean temporary pools. Other effects may also be involved, in particular those associated with the decomposition of organic material or modification of the soils, but they have not been tested for. Rhazi M.

The management of helophytes (rushes, Scirpus, etc.) therefore aims, as for woody plants, to reduce the amount of shading and the inputs of litter. In the case of helophytes, mechanical cutting (brushcutter) followed by removal of the cut material, may be accompanied by stripping*, a technique which involves stripping off the root mat, to thoroughly remove the plants (equivalent to stump extraction in woody plants) and to facilitate the reappearance of lightdemanding species (heliophiles). This second management operation must be fairly precise, and hence it is often carried out manually, to avoid removing any underlying seedbank which could possibly have survived beneath the helophytes. The maintenance of the cut areas should be carried out manually or by the use of controlled grazing.

Figure 32. Impact of light on the production of biomass and

spores in Isoetes setacea Mean belowground biomass production (bulb in g +/- S.E.)

of flooding (and hence terrestrialisation), the burying of the seedbank and the impossibility of germination for species with small, light-demanding seeds. It ends most commonly in replacement by commonplace plant and animal communities (with loss of specialised species and of the animals which only complete a part of their life cycle here). Management enables the accumulation of mineral and organic sediments to be limited, when its causes are well understood. The degradation of the vegetation in the catchment area is a classic cause of accelerating erosion of the catchment area and, as a result, of sedimentation in the wetlands downstream. The causes of this degradation may be brought under control through management (control of grazing, human pressure, vehicle tracks, etc.). At the minimum, a barrier of vegetation may be constructed around the edge to catch the sediment while allowing water to pass through.

0.18 0.16 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0.00 0

15 50 Light reduction (%)

75

85

Mediterranean temporary pools

Box 47. An example of management by removal of vegetation:

Lac des Aurèdes (Var, France) The artificial reservoir of Les Aurèdes, situated in the middle of the Escarcets Estate, owned by the Conservatoire du Littoral, was constructed in the 1960s and 1970s for use in fire defences. Its banks are subject to temporary flooding and support many species belonging to the Isoetion. In the absence of grazing, these areas are at present partly invaded by helophytes*: rushes (Juncus conglomeratus) and Scirpus (Scirpus holoscheonus). As part of the LIFE “Temporary Pools” project, experimental management by vegetation removal (simulated grazing) was undertaken in two areas, one dominated by rushes and the other by Scirpus, to assess the detrimental effect of these helophytes on the Isoetion assemblage. In these two areas, three homogenous sections (replicates) were marked out. Each section was then divided into two, a control zone and a treatment zone. In the areas with rushes and with Scirpus, the three control zones received no treatment and the three treatment zones were cleared every autumn, with removal of the cut material. In the area with rushes, in autumn 2001, stripping* was also tested in part of each treatment zone. In all zones the vegetation was studied using the quadrat transect method, in 2001 before any intervention (zero state), in 2002 and in 2003.

the soil water content allows large helophytes to grow, which compete with the Isoetion species; this was the case in the areas selected for vegetation removal. The appearance and maintenance of the Isoetion outside its optimal habitat therefore requires not only drastic control of the emergent vegetation but also favourable climatic conditions as was the case in 2002 (whereas there was a late flooding in 2003). Following the stripping, Isoetion species are thus colonising the habitat, but at relatively low density, possibly due to the disappearance of the seedbank below the root mat. Félisiak D., E. Duborper & N. Yavercovski

In the area with rushes, this number changed very little in the control zones. In the treatment zones, it increased from 3 (in 2001) to 8 (in 2002) and then 7 (in 2003). At the same time, in the stripped zone, it increased from zero to 4 and then 3. For the Scirpus areas, in the control zones it tripled between 2001 and 2002 (from 2 to 6 species), and then fell again to 3 in 2003. At the same time, in the treatment zones it increased from 2 to 12 and then 6. The effect of opening up the habitat was very positive in 2002 and a little less in 2003. However, the appearance of species of the Isoetion does not always correspond to the restoration of this plant formation. This only appears in its entirety on soils that are shallow (<15 cm) or even skeletal. If the soil is deeper than 20 cm,

Roché J.

Opening up the habitat had an effect on: • the total species richness, which increased from 66 species in 2001 to 105 in 2002 and then 77 in 2003, • the number of characteristic temporary-pool species (Fig. 33).

Experimental management of the Petites Aurèdes site (Plaine des Maures) by rush cutting

86

Juncus area 9 8 7 6 5 4 3 2 1 0

■ 2001 ■ 2002 ■ 2003 Control zones

Cleared zones

Stripped zones

Number of characteristic species of the Isoetion

Number of characteristic species of the Isoetion

Figure 33. Impact of the opening-up of the habitat on the number of characteristic species of pools Scirpus area 14 12 10 8 6 4 2 0 Control zones

Cleared zones

5. Management and restoration methods

Management of the herbaceous vegetation cover Some small species of high natural-heritage value may be very sensitive to competition from the herbaceous vegetation. They will be favoured if this vegetation is kept closely cut and sparse, and by micro-perturbations connected for example with the action of wild or domestic animals.

Creation The creation of a temporary pool first of all involves the creation of a depression which will hold water during the wet season. Once the depression has been created, there are several possible methods of establishing species, in particular plant species: • It is generally preferable to allow natural colonisation from nearby sources to take place by itself267. The proximity of functioning temporary wetlands, “potential reservoirs”, improves the chances of natural colonisation of artificial sites by specialised animal or plant species. It also increases the probability of the existence of suitable physical characteristics (substrate type, porosity, filtration, presence of groundwater, weather conditions,

etc.), which should be verified before undertaking any habitat creation works. • If spontaneous colonisation is impossible (absence of sufficiently close sites) or too slow, the re-introduction of animal and/or plant species may be considered. The organisms should come from the closest possible sites to minimise genetic contamination and to maximise the chances of success (growing conditions similar to those at the source sites). They should be in sufficient numbers to minimise the risk of genetic bottlenecks* in the populations. For plant species, the reintroduction will preferably be effected in the form of seeds, or of soil containing a diverse seedbank 62, 403. The introduction of seeds should take place before the autumnal flooding to maximise the chances of germination. Soil conditions will need to be suitable for the germination of seeds and the growth of seedlings. In addition, competition from more vigorous species should be controlled. In the early stages, protection against herbivores will assist with the initial development of the populations.

Box 48. Scirpus-Isoetes competition at Roque-Haute

The densities of Isoetes spores were as high within Scirpus areas as they were in Isoetes areas (10-15 spores per 100 g of soil, at a depth of between 0 and 3 cm, Fig. 34). The recent development of Scirpus was confirmed; it is probably linked to changes in the uses of the temporary pools, and in particular the cessation of extensive sheep grazing. Ageing of the pools could also be accompanied by nutrient* enrichment, facilitating dominance by Scirpus. Management that simulates grazing (close and regular cutting of Scirpus) or the resumption of sheep grazing should stimulate the Isoetes community by reducing the competitive advantage of Scirpus. Grillas P.

Figure 34. Density of Isoetes spores under Scirpus and Isoetes

formations ■ Under Isoetes ■ Under Scirpus Density of Isoetes spores (number / 100g soil)

In order to test the hypothesis that Isoetes setacea communities have been locally replaced by Sea Club-rush (Scirpus maritimus) communities in the pools at Roque-Haute, an assessment of the seed stocks was carried out. If Scirpus has recently replaced Isoetes, the densities of Isoetes spores, which are not very mobile, should not be significantly different between the two types of communities. Sediment samples (0-3 cm) were taken, at several pools, from areas dominated by Scirpus and Isoetes respectively. The density of Isoetes spores in the samples was evaluated by the germination method (from April to October).

30 25 20 15 10 5 0 0-3 cm

3-6 cm Sampling depth

87

Mediterranean temporary pools

Box 49. Grazing and the conservation of Teucrium aristatum

populations 823 800 700 600 500 400

■ 2001 ■ 2002 ■ 2003

300 250 200 100 0

0 Grazed zone

0

0

1

Ungrazed zone

Figure 35. Dynamics of Teucrium aristatum in the Lanau pool

Grillas P.

Yavercovski N., J. Boutin & E. Duborper

900

Number of plants of Teucrium aristatum

The Lanau pool, in the Crau (Bouches-du-Rhône) is the only remaining site in France for Teucrium aristatum, Lamiaceae285. Small, scattered populations are distributed within the outer belt of vegetation around the pool, in small bare depressions that are periodically flooded. The herbaceous vegetation has become tall and dense since the cessation of grazing in recent years. For this species, which is apparently very sensitive to competition from other herb species, extensive grazing appears to be a necessary condition for the maintenance of sizeable populations, or even for its survival. To test this hypothesis, part of the pool was returned to grazing and the numbers of the Germander were counted over three years in the two zones (grazed and ungrazed). A very significant increase in the population was observed in the grazed zone (Fig. 35). In the ungrazed zone, a single plant was found in 2003 to be growing in a bare area that was no doubt created by the activities of rabbits. Not only does grazing limit the density of the dominant vegetation cover, thereby reducing competition, but in addition trampling tends to create micro-depressions suitable for the germination of the Germander. The initial hypothesis appears to be confirmed and the area of the pool subjected to grazing should be extended, with continued monitoring.

Management of populations of rare species by grazing at the Lanau pool (France): grazed part on the left, exclosure on the right

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5. Management and restoration methods

Box 50. Reintroduction, reinforcing populations Reinforcement constitutes an important method for the maintenance of populations whose numbers are not sufficient to guarantee the survival of the species. These projects should be carefully controlled and carried out with great care if long-term success is to be guaranteed. There is an IUCN reintroductions “charter” which lists the operations to be followed394. In contrast with what has been achieved with other groups of vertebrates (birds, mammals), there are very few cases of amphibian reintroductions in Europe12, 91. On the other hand, operations to move populations have been carried out in several countries, for example France232, Spain332 and Italy354, 355. These translocations are carried out when natural habitats must be destroyed (e.g. for development) or when they cannot be restored, or when the risk of extinction of the species necessitates an increase in the number of populations. This method is appropriate when the decline is not associated with unresolved environmental issues. The results of these operations depend on several factors, including the number of individuals moved and the characteristics of the reception site. In the case of pool creation, decisions as to which type of aquatic habitat to provide must be based on a study of the environmental characteristics of the site, the presence of other wetlands nearby and an understanding of the particular requirements of the “target” species. The case of the Great Crested Newt Triturus cristatus Several translocations affecting Great Crested Newt populations have been carried out in Great Britain88, 89, 226, 257. Of 178 operations carried out, 37% were successful, 10% failed, and in more than 40% of cases the absence of long-term monitoring prevented any assessment. The probability of failure is high whether the translocation involves adults, larvae or eggs. Each stage has its own advantages and disadvantages which should be taken into account during a translocation. Moving adults poses two problems: fidelity to the original site (return to the site if the distance and the ground conditions permit) and poor adaptation to the new site (notably absence of familiarity with the terrestrial habitat). Movement of larvae would appear to be preferable as they have not yet developed the sensory capabilities required for orientation during their terrestrial phase: they will be capable of orientating normally during their migration. The disadvantage of using larval stages is the low survival rate during the immature phase. Translocation failure may be due to the poor quality of the receptor site. Some simple recommendations for evaluating the quality of this site are given in table 18. In southern France (Valliguières), a conservation project is currently being carried out with a population of Great Crested Newts by the Conservatoire des Espaces Naturels du Languedoc-Roussillon (CEN-LR). The excavation of an artificial pool close to the source pool is being planned from both the experimental and the operational point of view. This operation should allow breeding to take place more regularly and a second breeding site to be created which is designed to increase the population’s size and chances of survival (Box 26).

Table 18. Selection criteria for Great Crested Newt sites – Negative indicators

1. Absence of other amphibian species in the pool Especially the Palmate Newt which has similar habitat requirements. A site that is rich in amphibians constitutes a favourable factor unless there are competitor species (Marsh Frog, etc.). 2. Presence of fish and crayfish in the pool Fish and crayfish are predators of larvae and adults. Their presence may be disastrous for newts. 3. Visits by herons to the pool Herons are predators of larvae and adults. Their presence may be disastrous for newts. 4. Terrestrial habitat too restricted or degraded The terrestrial habitat close to the pool may support 250 adult Great Crested Newts per hectare. However, the absence of certain factors (hedges, woods, etc.) may be detrimental to this species. 5. Unsuitable aquatic habitat An absence of aquatic plants, needed for egg laying and the production of invertebrates, may be unfavourable for the survival of some amphibian populations. Herbaceous vegetation may allow amphibians to hide and escape from predators such as herons, etc. 6. Presence of a “barrier” in the terrestrial environment The presence of a swiftly flowing river, a major road or bare ground (arable land etc.) less than 100 m from the pool may be dangerous for “exploring” newts. 7. Public access The public may introduce fish or other undesirable species into the pool. Remote or inaccessible sites are preferable. 8. Presence of Great Crested Newts in the pool Adding a colony of newts to a pool which already supports them is almost never beneficial in conservation terms. 9. Absence of trees Tree cover can be unfavourable to predatory birds.

Lombardini K.

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6. Monitoring a. Why and how to conduct monitoring

- The precise objective of the monitoring should be formulated. This formulation cannot be limited to “Monitoring the population of such-and-such a species” or “Monitoring the intensity of suchand-such a phenomenon”; it could, however, be “To verify if pumping from the groundwater reduces the water supply to the temporary pool through springs” or “To verify that scrub clearing around the pool helps Isoetes to reappear in larger numbers”.

Perennou C. Monitoring in its broadest sense consists of the regular and standardised collection of data: the same parameters, usually collected at regular intervals, using the same method throughout. The term covers two different scenarios, the choice of which will depend on the objectives of the manager: • Surveillance, the aim of which is simply to find out the variation in time of the quantity being measured (the number of stalks of Marsilea in a pool, the number of breeding newts, the arrival or the expansion of an invasive species, the water levels or the eutrophication of a pool, etc.). The simplest and often the cheapest form of monitoring to implement, it is also the most widespread among managers. However, it has its limitations, which are not always fully considered, the main one being that it does not generally allow the causes of the phenomena observed to be identified after the event. Nonetheless, preliminary surveillance does enable changes to be measured and as a result, a monitoring programme to be commenced if necessary. Before carrying out measurements in the field, selection of the best and most appropriate methods and indicatorsa for the assessment of the situation (biological, socio-economic, etc.) is essential. • Monitoring (in the strict sense) has more ambitious objectives: to identify the causes of the variations detected (for example, “What has caused the decline of the Great Crested Newt on my site?”) or to verify that a parameter deemed essential remains within acceptable limits or develops in the desired direction. This monitoring could accompany a management operation to verify that it is having the desired results (recovery of numbers for example). The results of the monitoring enable the management of a site to be adapted if necessary. In this sense, monitoring is a vital tool for the adaptive management of habitats. If managers wish to discover the causes of a phenomenon of interest to them, to gauge the response of the habitat to a management operation, etc., the putting in place of genuine monitoring often requires the measurement of additional parameters to those of simple surveillance of the phenomenon. A framework for drawing up such a programme is set out in the MedWet Monitoring Manual (Tomas Vives388 downloadable on www.wetlands.org/pubs&/ wetland_pub.html#MW5). To summarise (Tab. 19), a monitoring programme can be drawn up145 step by step, the main points of which are as follows: - The prior precise identification of the problem/question to tackle is essential: a formulation that is too vague will prevent the development of a rigorous monitoring programme.

a. It is essential to distinguish carefully between the indicator and the phenomenon of interest to the manager. For example, eutrophication is a complex phenomenon, which can be assessed through indicators of the type “Concentration in the water of nitrates or phosphates”; but eutrophification does not consist solely of these parameters.

90

- It is essential to formulate a hypothesis regarding the expected development of the phenomenon being monitored; this enables monitoring in the strict sense to be distinguished from surveillance for which the trends of the parameters being monitored are not identified at the start. - A monitoring programme can only respond to the precise question for which it was created. Its results will not generally be appropriate for responding to any other question, even one that is ostensibly similar. The outcome of a monitoring programme is an operation or a choice of management (stage 10) relating to the problem raised at the onset (stage 1). For a site manager, merely increasing knowledge, without any resulting implications for management, does not generally justify the implementation of monitoring programmes which are costly both in time and financially. Thus, a monitoring programme in the strict sense is similar to scientific experimentation in the rigour of its formulation and its approach based on hypothesis and deduction. Henceforth in this chapter, the word “monitoring”, unless otherwise stated, will refer to both surveillance and monitoring in the strict sense as described above. Collection and analysis of data The choice of monitoring methods should be made by considering not only the objectives of the monitoring but also the methods of data analysis and the costs. A pilot study is strongly recommended in order to evaluate the whole of the protocol so Table 19. MedWet framework for monitoring

1. Identify the problem/question
2. Define the objective
3. Establish the hypothesis
4. Choose the method and the variables
5. Evaluate the feasibility and the costs
6. Pilot study
7. Collection of data (fieldwork, etc.)
8. Analysis of data
9. Interpretation and communication of results
10. Management operation and evaluation

6. Monitoring

the interannual variance of the variable (abundance, for example) and increases the difficulty of detection of ecological variations or the effects of a change in management which will only become apparent after a few years. Cupular pools are sometimes so small that their surface area does not allow a sufficient number of samples to be placed to conform to statistical requirements. The possibility of using small-sized samples, thanks to the very small size of the plants, sometimes helps to resolve this problem by increasing the number of samples. The physical properties of the habitat, and therefore the vegetation and many animal species, are organised in gradients along the topographic gradient. Depending on the objective of the vegetation monitoring, the distribution of the measurement points may be regular over the whole of the pool, spaced out over the various belts, or linear, parallel to the main gradient, in order to evaluate the change in distribution of the species through time.

as not to invest too much in a monitoring programme. Many monitoring methods can be used and it is not possible, within the context of this management guide, to carry out a systematic review. Before beginning a monitoring programme, it is preferable to consult specialist works, especially with regard to methods of measurement and data analysis73, 129, 142, 346, and/or consult a specialist. The type of sampling, the permanence or otherwise of the recording stations, other aspects of data collection (season, frequency, etc.) and the methods of analysis of subsequent data should be chosen in close collaboration with a specialist in the field concerned. Otherwise, there is a risk that it will be impossible to subject the data collected to a rigorous interpretation (insufficient frequency, unsuitable period, etc.) or that fieldwork will be unnecessarily heavy (time wasted in carrying out more measurements than are required for the question posed, for example). Certain physical and biological characteristics of Mediterranean temporary pools, as well as their interannual dynamics, must be taken into account in the choice of methods and protocols. Some examples below illustrate the distinctive features of temporary pools, and methods suitable for these habitats are described in the following chapters (6b to f). The great temporal and spatial variability in the abundance of species poses practical problems for the siting of recording positions and the frequency of readings. This irregularity increases

It must be stressed that the more ambitious the objective of the monitoring, the more costly it will be, notably in terms of time for the collection of data. It is therefore often preferable for the manager to start from the resources available (“How much time can my team devote to monitoring each year?”) and to define a realistic objective with this constraint in mind, rather than fixing an objective which calls for resources that are not available, with the result that the work is only half completed.

Figure 36. Water cycle

Solar radiation

Atmospheric circulation

Rain and snow clouds

Cloud formation

Precipitations

Snow and ice Transpiration Evaporation Water table

Evaporation

Run off Rivers and lakes

Ground water

Ocean Salt water

91

Mediterranean temporary pools

b. Hydrological monitoring Chauvelon P. & P. Heurteaux The establishment of a quantitative assessment of the hydrological functioning of a water body requires the censusing of the components of the water cycle (Fig. 36) involved in this functioning. An adequate knowledge of the geographical and geological characteristics of the habitat studied, plus a minimum of measuring equipment (metrological capacity), are essential. The geographic and geological characteristics to be ascertained have already been mentioned in Chapter 3b. They are obtained through the thorough study of all the documents which can be assembled regarding the extended environment of the site studied: topographical maps, geological maps, pedological maps, aerial views (photos and/or satellite images). These data enable the crest lines defining the catchment area to be detailed, its surface area to be calculated, its topography and its vegetation to be assessed, its lithology to be understood (stable rocks, porous rocks, karstic networks) and the possible involvement of the underground water in the surface water cycle to be assessed. This information will facilitate the inventory and the description of modifications to the catchment area likely to have an influence on flows (ditches, drains, etc.) Additional information will often be necessary: topographical surveys to clarify the map contours and produce a detailed bathymetry of the water bodies (Box 51), characterisation of the sedimentary substrate (texture, structure, stratification) both at the bottom of the pool and in the surrounding area to a depth at least equivalent to the level of the bottom of the pool. Metrological capability relates primarily to monitoring water levels in the pool and quantifying rainfall, evaporation from open water and evapotranspiration. Bear in mind that hydrometric equipment installed in a public place is open to the risk of theft or vandalism. Measurement of levels (Box 52) should be carried out regularly. Automatic continuous readings are obviously the best solution. Though there may be no other option but occasional measurements, two measurements per month would seem to be a minimum. If possible, the measurements of rainfall events should be made at the latest one or two days after they have finished. It is best not to be tied to fixed dates, as there is little chance that the dates of the visits will coincide with interesting hydrological events. To quantify rainfall, the data from existing observation networks is usually used (Box 53), despite the considerable spatial variability of rainfall, especially in the Mediterranean region where rainstorms predominate. When the density of pluviometers is insufficient, and for a precise reading, measurement on the site, i.e. within a kilometre and at the same altitude, will be necessary. Estimates of water losses to the atmosphere (evaporation and evapotranspiration) are usually made by calculation from climatological data, using empirical formulae. All require at least the air temperature in the shade and other more elaborate ones, such as that of Penman293 require, in addition, the air humidity, solar radiation and/or the duration of sunshine, and the wind speed.

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Box 51. Topography and bathymetry The bathymetry of the pools studied can be obtained fairly easily by a comparative method in relation to the calm surface of the water body, at a period of maximum water level of the pool. All that is needed for this is a tape measure, a depth gauge and some good waders. It is advisable to have at least two markers fixed to the ground, aligned along the major axis of the pool: one in a “central” position and the other on the edge or on the bank. These clearly visible markers (bench marks, solidly fixed pegs) will serve as a reference for the geometric description of the site and monitorings. As a basis for description, we suggest then measuring the depths across four to eight transects regularly spaced along a reference axis formed by the two bench marks on the ground. The density of transects in the pool and the number of measurement points per transect vary greatly according to the topography: they will be low on regular gradients and increase when the gradients are irregular. For monitoring that combines accuracy, quantity of data and economy of time, professional topographic equipment is needed. With an electronic theodolite or tacheometer with laser rangefinder and two operators, several hundred readings can be acquired per day with one centimetre accuracy, and stored in the memory for direct informatic use. Once the reference station has been set up, bi-frequency differential GPS allow readings with one centimetre accuracy to be taken by just one operator on the ground, who can move in a radius of several kilometres around the reference site to take the point readings. These measurement devices are costly, but both types can be hired (around 1000 € per week for a differential GPS, and daily hiring is also possible). Basic training is required on how to use them, provided by the hire company. When budgets are limited, but personnel are available and time is not limited, it is possible, for the price of a week’s rental, to purchase geometer optical equipment which can be used time and time again. Chauvelon P. & P. Heurteaux

Few managers will have the chance to measure these parameters themselves with the aid of an automatic meteorological station on their site. The data can be provided by organisations managing measurement networks. In France, these data can be obtained from Météo-France, and the INRA – at a price - and possibly from the agriculture (DDA) or equipment (DDE) services of the French départements. The actual evapotranspiration (ETR) of a plant cover is not calculable from field data and the method commonly used consists in using a reference climatic value: the potential climatic evapotranspiration (ETP). According to the water content of the substrate, the ETR of a plant cover will represent a certain proportion of the ETP.

6. Monitoring

Box 52. The measurement of surface water levels A water level gauge can be purchased commercially (in enamelled iron) or made by hand. In principle, the zero of the scale should correspond to the deepest point of the pool. The water level should be capable of being read from the bank (with or without binoculars). The installation of a water level gauge at the deepest point of the pool can pose logistical and/or aesthetic problems if the variations in water level are significant. If the configuration of the pool allows it, an oblique gauge can be placed leaning against a bank, in which case the angle of inclination must be taken into account to correct the reading. In all cases, an installation which is easily visible and accessible runs the risk of vandalism. If the risks or technical difficulties make the placing of a water level gauge impossible, one or more discreet and stable markers can be installed in the pool after their spot height has been measured in relation to the deepest point of the pool. The depth of the water is then measured by placing a pole vertically against the marker. This is a simple and fairly cheap method of recording the water levels at regular time intervals. However, in the case of sites which are difficult to access or lack personnel, it does not enable information to be obtained corresponding to the critical phases of sudden variations in the levels. Whenever this is possible, the use of recording devices is preferred.

Relative proportions of sources of water It is difficult to quantify how much water in a pool is supplied by the run-off from its catchment area or by underground water. When investigation proves possible (loose rock, sands, silts, not too pebbly), it is useful to survey the underground hydrodynamics by installing and using a network of piezometers (Box 54). On fissured bedrock or a very pebbly formation, “light” prospecting (hand auger) is not possible. In the hope of improving understanding of pool-groundwater interactions, one could in this case just locate the wells and springs likely to exist on the catchment area, and compare the change in the levels and the electrical conductivity of water* in these wells and springs with those of the pool. This approach implies topographic survers which are often difficult to ascertain.

A limnigraph is a device which records the variations in water level continuously. There are several models in existence (mechanical or electronic float limnigraphs; pressure sensors). Their price often makes them unaffordable, especially as they run the same risks as the water level gauge.

Roché J.

Chauvelon P. & P. Heurteaux

At Valliguières, the influence of karstic water on the pool has been established through piezometric monitoring

93

Mediterranean temporary pools

Pluviometers are open-top receptacles which capture the rain that falls on their surface. In theory, nothing could be simpler, but in fact the intermittent nature of rainfall, the turbulence created by wind and the apparatus itself affect the representativeness of the measurement when extrapolated to a whole site. The size of the receiving surface, on the other hand, only has a limited influence on the percentage of rain collected321. Ideally, it is better to distribute several small gauges over a site than use one single large one. There are several types of cummulative pluviometers. For all of these, it is important that the measurement is taken shortly after a rainfall event. In France the most commonly used model is the “Association” pluviometer (“Association Scientifique de France”). This consists of a bucket surmounted by a funnel, the opening of which is a rigid ring of 400 cm2 chamfered on the outside. The instrument is placed on a support. It is made of zinc or plastic. The measurement of the rainfall is made in a collecting tube graduated in millimetres and tenths of millimetres of rain. A millimetre of rain corresponds to one litre per m2. The pluviometer should be positioned according to standardised conditions: receiving surface horizontal, between 1 m and 1.5 m above the ground. To avoid interference from nearby obstacles (trees, buildings, etc.) it should be set apart at a distance of at least three times the height of the nearest obstacle. Pluviometers installed in places open to the public have very little chance of survival. In this case, it is best to look around in the neighbourhood of the site to locate “private” pluviometers, or look for an accommodating landowner who is willing to host the apparatus and take readings. In all cases, data should be obtained from the nearest meteorological station, bearing in mind that there is often a charge made for data. There are self recording rain gauges (tipping bucket rain gauges, float type raingauges) which record continuous rainfall events. Storage raingauge also store rainwater. These instruments are practical on sites with difficult access or when there are not enough personnel for daily collection of the data. It is even possible to make a storage raingauge oneself (Fig. 37). Simply solder a nozzle to the base of the funnel of a “Association” pluviometer or any other receptacle (large food container, catering size, whose receiving surface is measured, and into which white cement is poured in a slanting form to channel the flow, to prevent splashing and act as ballast) and using a flexible plastic tube, link it to an opaque flask placed in a carefully insulated case (buried if possible). The opacity prevents the growth of algae. The receiving surface is supported by a hollow metal tube (central-heating type) into which the plastic tube passes, protected

94

from the light. If readings occur at very irregular intervals, some drops of paraffin oil and formalin in the flask prevent evaporation and the putrefaction of organic debris (bird droppings). Gloss paint facilitates the slide of raindrops and protects against corrosion. The volume of rainwater collected is measured in a collecting tube or by weighing the tared flask (to the nearest gram or tenth of a gram, if possible). As the area of the receiving surface of the pluviometer is known, the volume measured can be converted into the rain depth. Thus, with a pluviometer of 400 cm2 and a 10-litre flask, up to 250 mm of rainwater can be stored. The rain depths measured should be rounded up to the nearest millimetre. To minimise soiling, it is sometimes necessary to equip the receptacle with a perch for birds (small metal rod). Heurteaux P. & P. Chauvelon Figure 37. A home-made cumulative pluviometer Receptacle Perch White cement for slope

Flexible plastic tube, ø 8-10 mm

Food container

Rigid support ø 1” ou 3/4”

The volume of the storage receptacle depends on the receiving surface

Box - insulated or buried

Air inlet Flask

Soil

Pierre Heurteaux

Box 53. Measurement of rainfall

6. Monitoring

• What is a piezometer? A piezometer is a device for looking at groundwater. It consists of a pipe installed in the ground which goes down into the groundwater, theoretically as far as its impermeable substrate. A filter allows underground water to enter the tube as far as the groundwater level, the variations in which can then be measured. The water can also be extracted for analysis. • What information can piezometers provide and how can this be obtained? To have an overview of the dynamics of the groundwater and its possible connection with a water body, several piezometers must be installed. Their minimum number and spatial dispersal depend on the configuration of the terrain, and specialist advice is desirable at this point. The ease of the work, the security of the installations and the time that can be devoted to monitoring should also taken into account. The transect method is usually recommended for evaluation of the position of the groundwater and its gradient. For example, along a specified axis, a line of piezometers is installed at 0, 2, 10, 50 and 100 m from the edge of the pool (plus one in the pool if possible). • What materials and methods are required for making and installing piezometers? The methods of installing piezometers (foreshaft by drilling, shaft sinking by piling), the constituent material (metal, PVC), the filter and the diameter of the tubes depend on the nature of the terrain and the type of measurement of levels to be performed (instantaneous measurements or continuous recording). If the terrain is not very pebbly loose rock and the groundwater fairly shallow, it is easy to make piezometers with standardised fairly thick PVC tubing to prevent distortion. They are installed in a hollow foreshaft excavated with a hand auger, as vertically as possible. The filter is usually a piece of nylon stocking, attached to the base of the tube by a steel wire (or clamp) and protected by a sleeve of gravel if necessary. The best period for installing piezometers (Fig. 38) is mid-summer, when water levels are at their lowest. On loose terrain (sand), it is not easy to work in a saturated habitat. When the foreshaft has been dug (phase 1, Fig. 38), place the piezometer in it as vertically as possible. Pour some siliceous gravel around it, then pull up the tube by a few centimetres, thus creating a small permeable sleeve (phases 2 and 3). With the earth taken from the foreshaft, make a fairly liquid mud, then pour it in and pack it down in the foreshaft around the piezometer (phase 4). In habitat prone to flooding, the aerial part of the piezometer should be fairly long to avoid the risk of it being submerged. To protect the base of the tube from unwanted infiltrations, it is recommended that it be placed in the centre of a casing (a piece of tubing of larger diameter) pushed into the earth to a depth of around 20 cm, and filled with soil (phase 5). The piezometer should be capped, but free communication with the atmosphere should be ensured. For instantaneous measurements of the piezometric level, PVC tubing, 45-50 mm in diameter, is suitable. The foreshaft is then dug out with a Helix auger, 100 mm in diameter (or 125 mm, see below). For recording variations in water level, the diameters of

the foreshafts and the piezometers should be adapted to the recording equipment. For a floating system of 80-mm diameter, use a hand auger with a diameter of 150 mm and a PVC tube with a diameter of 120-125 mm. The foreshaft can be made with a hand auger with a diameter of 125 mm and a PVC tube with a diameter of 95-100 mm may be used, but in this case particular care should be taken to ensure that the system is vertical. • How to read the levels in piezometers The best solution is of course to purchase a limnimetric probe which will indicate water levels by light or sound. A light probe can also be made fairly cheaply, modelled on the one described by Heurteaux185. For very shallow groundwater, a rigid probe made of dampening material (a graduated wood rod for example) will suffice. • How to extract water from the piezometers In semi-permeable terrain, water can remain for a long time in the piezometers. Before any sampling of the water, it is thus advisable to draw off the water (or even empty the tubes), wait for a few minutes, then take the water from the bottom of the tube. For this, pumping is necessary. For shallow water, a small hand vacuum pump will suffice (manual bilge pump, for example). Heurteaux P. & P. Chauvelon

Figure 38. Making and installing piezometers 1

2

4

3

5 Stopper

Hand auger

PVC tube Casing

Air inlet Water

Siltation mud

Loose soil Pierre Heurteaux

Box 54. Measurement of underground water levels using piezometers: simple methods of implementation

Filter

Collar

Gravel sleeve

95

Mediterranean temporary pools

c. Vegetation monitoring Grillas P. & P. Gauthier Vegetation monitoring generally aims to provide evidence of the effect of habitat changes (hydrological regime or soil thickness, for example) on the whole of the vegetation or on certain species in particular. Monitoring involves defining, in advance, reference state and the range of variations around this “norm”, judged natural or acceptable. In the case of temporary pools, previous knowledge of the amplitude and frequency of the natural variations, under the influence of meteorological conditions in particular, is very important. Within the framework of a monitoring programme, two series of variables should be measured: those concerning the management objectives (of rare, characteristic, invasive species, etc.) and those concerning the biotic or abiotic factors which could explain the changes. In temporary Mediterranean pools, the choice of methods will be influenced by: • Characteristics linked to the habitat: - the instability of the vegetation and hydrology, - the surface area, sometimes very small, - the water depth, which can vary greatly (karst pools, turloughs, poljes, etc.) in time and with strong spatial gradients. • Key parameters of the typical vegetation of this habitat: - the number of annual species with a short life cycle, - the frequency of small-sized species, - the impossibility of identifying separate individuals in many species (vegetative multiplication), - the presence of tall plants, which can sometimes be dominant (shrubs, helophytes), - the existence of a seedbank. Most of the techniques described require data collection over at least two to three years, and preferably over five to ten years, to be able to quantify the impact of the natural evolution of the habitat or of management measures. Given the rapid succession of species, these techniques usually require measurements taken over the whole of a vegetation cycle. Failing that, managers should target visits in relation to the peak of vegetation, the visibility or the stage of development of the species being monitored, and more generally, the question to which an answer is being sought.

The inventory This is a list of the species observed on a site, the compilation of which will require several visits as species succeed one another during the annual cycle. Because of the irregularity of emergence of some species, this can also require several years of observations. An inventory is especially advisable during exploratory studies, for drawing up a site assessment and for describing the development of species richness during restoration or creation projects167.

A very rare species with scattered individuals (easily countable) can undergo a total count, possibly accompanied by mapping of the individuals, combined with supplementary data (topography, etc.). The accuracy of the method depends on the probability of detection of the species (size, colour, etc.). Mapping will be facilitated by a marked grid at the study site, thus limiting the risks of overlooking individuals or counting them more than once, and above all enabling the spread/decline of the species to be monitored over a number of years (Fig. 39). To enable a population assessment to be made the count should be supplemented with measurements of demographic parameters: reproduction, seed production, number of seedlings reaching reproductive maturity, etc.167 To define the real size of the population (decline, stability or increase), a study of its seedbank (see below) will be necessary. In the case of a species with greater densities, for which exhaustive censusing is impossible sampling using permanent quadrats is preferred. Within a quadrat, the species are characterised by their presence/absence, their cover, their frequency and their numbers. For the species of temporary pools, which are generally small in size, a quadrat with sides of 25 to 50 cm will normally suffice. Only plants rooted inside the quadrat are counted, but the main point is to keep a constant criterion between quadrats. The larger the number of quadrats, the greater the accuracy of the estimates. The cover is the most commonly used method in the study of vegetation176, 207. It consists in estimating the projection onto the ground of the surface of each species, the vegetation being subdivided into strata (tree, shrub and herbaceous, for example). This method is only rapid and effective if the researcher is experienced or the vegetation studied simple (one or more scattered species). The discrepancies between inexperienced observers will increase with the complexity of the vegetation structure (number of species, diversity of growth forms). For this reason, measurements which are less accurate but less sensitive to a change in observer are preferred367. Thus the abundance (or frequency) of a species can be measured in quadrats divided into squares. For example, in a quadrat with sides of 30 cm subdivided into 9 squares with sides of 10 cm, the abundance will be measured as the number of squares (0 to 9) in which it is present. The quadrats can also be redistributed randomly each year.

Figure 39. Monitoring of a rare or scattered plant species with

the aid of a permanent grid

A 1 2 3 4

Monitoring a rare, threatened or invasive species Depending on its density at the study site, different protocols may be considered.

96

5

B

C

D

E

6. Monitoring

The cover of a species on a given surface can also be evaluated by the analysis of a photographic image. This method has now been facilitated by the ease of use of digital photography and image processing. It is suitable for simple communities (1 or 2 species) on bare soil, as it requires a significant contrast between the substrate and the vegetation. The density of Marsilea in dry pools at the end of the summer could, for example, be obtained in this fashion.

Monitoring emergent plant communities Zonation into vegetation belts is often recognised in temporary pools (Chapter 3c), along the hydromorphic gradient. A transect (permanent or otherwise/temporary) is the most pertinent method of monitoring the variations in vegetation along this gradient. In this case, the transect consists of a line established perpendicularly to the vegetation belts (Fig. 40) and cutting completely across the pool or as far as its centre. Depending on its size and topography (homogeneity), one or more transects are established, in parallel or perpendicular to one another.

Transect 1 Transect 2 Transect 3

Transect 1

Transect 2 Figure 40. Putting in place vegetation transects in temporary

Grillas P.

pools

Monitoring of vegetation dynamics using the quadrat transects method in a pool at Mamora (Morocco)

97

Mediterranean temporary pools

R9 R7

R5

R8

R4

R6 R5 R3

R3

R4

R2

R2 R = reading

R1

R1

1 - Continuous transect The plants are counted on identical and continuous segments along the transect line

2 - Discontinuous transect The plants are counted on the line, over 20 cm every 40 cm for example

R9 R8 R3

R7 R6 R5

R2

R4 R3 R2

R1

R1 3 - Quadrat transect The plants are inventoried (presence/absence, counting, etc.) inside quadrats set at regular intervals or continuously along the transect line

Figure 41. Different measurement methods used for monitoring the vegetation along transects

A transect has the advantage of ease of implementation but the disadvantage of low spatial representativeness. Different measurement methods can be implemented along the transects: • Measurement by points consists in noting all the plants which touch a pointer stuck regularly into the vegetation. It requires much time and rigour, and does not enable spatial analysis of the data (the averages are obtained by species and by transect). • Measurement by segment consists in taking an inventory of the species on segments of consistent length (for example 10 cm) arranged continuously (Fig. 41-a) or at regular intervals (for example 0.50 m) (Fig 41-b). The lengths of the segments and the intervals enable adaptation to varied situations. • Measurement by quadrats follows the same principle as segments but enables, at each point, a larger number of species to be censused and their abundance to be quantified. This method thus enables spatial analysis of the abundance data along the environmental gradients (Fig. 41-c and d).

98

Monitoring at permanent measurement points, possibly within a protocol of stratified samplinga per zone, is often preferred: its disadvantages in term of representativeness and independence of the data are largely compensated for by ease, implementation time and the ability to identify changes. The permanence of permanent marker pegs can be a problem in temporary pools where they are regularly unearthed because of the winter flooding which loosens the soils, and disturbance by humans and animals (wild boar, livestock). Discreet marking of plots which are buried and barely visible above the ground is preferable, even if they are

a. Stratified Sampling: When the subject of study has a distinctive and well-known spatial organisation (as opposed to a random distribution), the sampling protocol is based on this distribution. For example, if it is thought that the depth of the pool influences the species richness, an equal number of deep and shallow pools are chosen, so as not to oversample the most common category (to establish uniform sampling intensity according to a predefined typology).

6. Monitoring

more difficult to locate again. Some markers can be carefully placed outside the pool and used, at each reading, to re-establish the reference axes.

Study of the seedbank Estimation of the seedbank is necessary for evaluation of the size of a population of annuals with dormant seeds or the capacity of a species or suite of species to regenerate after a perturbation (Chapter 3c). Such a measurement is not generally within the means of the manager (cost, infrastructure, etc.). Nonetheless, in the case of a species with high natural-heritage value, managers may wish to carry this out in collaboration with a specialist. Study of a seedbank begins with standardised sampling of the sediment (sample boring). The diameter and depth of the core are adjusted to the size of the seeds, the depth of the substrate and the purpose of the monitoring: generally 2 to 20 cm in diameter. Seeking seeds below 5 cm in depth is only justified in particular cases, such as the burying of seeds by sedimentation, ploughing or disturbance by wild boar (Boxes 38 and 41).

The smallest mesh is generally from 0.15 to 0.20 mm. The seeds are then identified under a binocular microscope. This technique provides an inventory and an estimate of the relative abundance of the seeds, but does not give any information on their viability. In this way, an overestimation of the viable stocks is obtained which can be evaluated by supplementary germination tests. Such tests require the knowledge of the germination conditions of the species being researched and can be very complicated to carry out (pools with over 100 species!). Indirect counting of viable seeds from seedlings consists in putting soil samples into optimum conditions for seed germination. This method requires an adequate infrastructure (greenhouse, air-conditioned enclosure) for the germination experiments and control of the germination conditions of the plant species. It provides an estimate of viable seeds but tends to underestimate seed stocks: all the viable seeds will probably not germinate. Moreover, this method requires the ability to recognise plants at the seedling stage, as they will not necessarily reach the adult stage during the experiment.

Two techniques with different results can then be envisaged, depending on the objective: direct counting of the seeds or putting the seeds found in the soil into germination conditions. Both rely on relatively intensive procedures (in terms of time and accuracy).

For bryophytes*, the monitoring problems are more or less the same as those for vascular plants (Hugonnot & Hébrard, pers. com.), though the use of the transect is less common367. Furthermore, the identification of the species in the field is often more difficult or even impossible for some groups. Sampling for laboratory identification, which can disturb the habitat, is thus necessary more frequently than for vascular plants.

Direct counting of the seeds is carried out after their extraction by sieving with a series of sieves with meshes of different sizes.

The main methods used according to the objectives pursued are summarised in Table 20.

Objectives

Methods possible

Inventory

Repeated visits to site

Monitoring of a scattered species

Count and detailed mapping

Time

Other costs

Level of knowledge required

*

*

**

**

*

*

Monitoring of a more abundant species Permanent quadrats

**

*

**

Monitoring of a community

Permanent continuous transect

**

*

**

Permanent discontinuous transect

**

*

**

Permanent transect of quadrats

**

*

**

***

***

***

**

**

***

***

***

***

Study of the seedbank

Direct count Indirect count Mixed technique

Table 20. Evaluation and objectives of vegetation-monitoring methods

* = low, ** = moderate, *** = significant

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Mediterranean temporary pools

d. Amphibian monitoring Jakob C.

General points Monitoring is influenced by the life cycle The methods used for the monitoring of amphibians mainly concern the aquatic phase, when the animals are concentrated in pools and, for some species, night sampling. In most cases, visits must be synchronised with breeding periods, which are often linked to periods of rain. Sampling of adults is thus constrained compared with the sampling of larvae, which can be carried out by day or by night and over longer periods.

Box 55. Exploring a new site On an unknown site (for example a plateau, or massif with an unknown number of pools), exploration begins by nocturnal location after heavy rainfall and when there is a fairly high air temperature (not below 13°C) in autumn (October-November) or spring (February to April, for periods conducive to breeding, see Fig. 42). The localisation of the places (pools) occupied may then be made by listening, thanks to the vocalisation of some species (essentially frogs, Stripeless Tree Frogs). After this localisation phase, the usual methods of inventory can be applied. Jakob C.

The inventory Breeding Like other groups of animals of temporary pools, the breeding of amphibians varies greatly from one year to the next (Box 21, Chapter 3d). It is thus difficult to differentiate fluctuations in populations in the long term from variations observed in the short term. Some species are characterised by considerable flexibility enabling them to adapt to interannual variations in rainfall, while others are more stable (Box 22, Chapter 3d). For the monitoring of amphibians, several parameters are important: the choice of the period of the sampling, the necessity of repeated visits during favourable periods, the importance of monitoring over several consecutive years and the correlation of samplings with the data of a local meteorological station and the physical data of the habitat, for a correct interpretation.

Legislation and protection Amphibians are protected by law in most European countries. On French territory, all species are protected by law (Arrêté du 24 avril, JO 12 mai 1979) except for Rana esculenta and Rana temporaria which are covered by special legislation. Thus for all monitoring projects involving the handling of amphibians, authorisation must be applied for in advance. This is given by the préfecture of the département in France and by the Comunidades Autónomas in Spain. In addition to these administrative procedures, these animals, adults or larvae, must always be handled with extreme care. Their skin is particularly fragile, especially those species covered with mucus. Handling should be kept to a minimum. Some advice: • Variability in time: strong interannual variations in breeding can occur (Fig. 42); for a complete inventory, it is thus advisable for monitoring to take place over at least three years. • The methods presented are suitable for the small surface area of temporary pools. • A combination of several techniques in the field is advisable. • The techniques presented are based on the experience acquired with the temporary pools of southern France; there are of course other methods, not dealt with here121, 187.

Methods The choice of methods depends mainly on the objective sought, but should take into account technical demands and cost. The results that can be obtained are essentially an inventory, an evaluation of the size of the population and demographic monitoring.

100

The inventory consists in making up a simple list of the species present on a given site. Depending on the timescale and the method used, this list of species can vary considerably. The most conducive period for the observation of amphibians must then be chosen (see Fig. 42) and some verification observations possibly carried out outside of this period. In southern France, the most suitable periods are October-November for the autumn period and February to April for the spring period. There are several methods: • Visual detection of the adults preferably takes place at night, with the aid of a torch, close to potential breeding sites. This protocol is easy to follow. It requires a minimum of equipment and enables comparisons to be made between sites when the observation effort is standardised (number of man-hours). The only constraint with this method is the ability to identify species. Under certain conditions, surveying by day can also yield good results, particularly at the time of the emergence of recently metamorphosed individuals (May-June, especially in southern France). In this case, this involves seeking animals in the immediate proximity of the pool, under nearby stones or other objects. • The auditory count (by night) consists of night sorties to identify the species present by their characteristic songs. The protocol is simple, the equipment is minimum and the observation effort (number of man-hours) can be standardised between sites. On the other hand, this method is limited to singing amphibians (some Anura only) and can only be applied under certain meteorological conditions (rain, no wind, high temperature for some species such as the Western Spadefoot). For large sites, it is more difficult to implement due to the limited range of the song. In this case, it can be combined with transects (cf Chapter 6d). Knowledge of Anura songs is essential, except if recordings are made and given to specialists. • Sampling of larvae is carried out by means of a pond net with a fairly large mesh (2 to 3 mm) dipped regularly to different depths of water in the pool. The collection of larvae should be carried out with extreme care, as they are very fragile (especially newt larvae). For identification, they are placed in a fully transparent receptacle so that the entire animal can be observed. The larvae should be released as soon as possible after their identification. Using this technique, an exhaustive list of the amphibians breeding in the pool can be obtained for any given year. In southern France, monthly sampling from February to June will theoretically enable all the species to be obtained. Advantages include

6. Monitoring

Figure 42. Monthly occurrence of tadpoles of several amphibian species (pools of Roque-Haute, Hérault) over three years of monitoring (based on Jakob196) in 184 pools at Roque-Haute

■ 1997 ■ 1998 ■ 1999

Rainfall (mm)

2000

Rainfall

1500 1000 500 0 Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

30

Bufo calamita

20 10 0 Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

40 30

Hyla meridionalis

20 10 0 Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

6

Pelobates cultripes

4 2

Number of occupied pools

0 Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

15

Pelodytes punctatus

10 5 0 Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

6

Rana perezi

4 2 0 Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

25 20 15 10 5 0

July

Aug.

Sept.

Triturus helveticus

Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

30

Triturus marmoratus

20 10 0 Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

101

Mediterranean temporary pools

• Trapping: there are two main types of traps for this kind of inventory: - A light trap consists of a transparent plastic cube, with funnelshaped openings in the sides. There is a source of light inside. The cube floats on the surface of the water and the openings are under the water. The tadpoles and larvae are attracted by the light and remain trapped inside. This method has the advantage of enabling sampling in inaccessible zones and minimises the sampling time and therefore disturbance of the habitat. The costs of the traps (around 100 € each) or the time taken to make them are constraints to be taken into account. Moreover, they are often inadequate for the entire water column (size, volume of the pool), and can thus only be used to supplement other methods. Some predators of larvae can also enter the traps. - The technique of shelter traps consists in placing artificial or natural shelters close to the pool to attract amphibians: piece of fibrocement, plank, flat stone. These shelters are used by the adults and the larvae at certain times of the year (autumn and spring especially). This enables the species found to be inventoried during the day and certain important breeding phases to be dated, notably the emergence of the larvae. This technique is especially effective for newts, the Parsley Frog, toads of the Bufo genus, the Alytes genus and Painted Frogs. Recommended field guides: for Europe, two recent works are particularly recommended: Nöllert & Nöllert281 and Arnold & Ovenden17. For France, Duguet & Melki121 give an identification key for the adults, the larvae and spawn as well as an audio CD of all the songs, and Miaud & Muratet265 include two identification keys (one for the eggs and the spawn, and one for the larvae and the tadpoles) illustrated by photos. For the Iberian Peninsula the work of Salvador & Garcia Paris334 is excellent for the identification of adults (drawings and photos for identification criteria) and larvae (key in form of drawings).

Population size To count the number of individuals of a species, the methods become more time consuming. All depend on the accuracy required, the time available and the species present, which have been previously identified by an inventory. • Auditory counts: this method is similar to that described above, only here the aim is to quantify male singers. Repeated counts in the spring, or in the autumn, can be necessary. The number of animals is usually noted in classes (1, <10, <50, <100, etc.) especially for species in which the male singers appear at the spawning site synchronously (Parsley Frog) or in large numbers (Stripeless Tree Frog, Green Frog). This method is suitable for pools of small or moderate surface area and in low numbers, but difficult to implement on some sites with a network of neighbouring pools. This is the case for example with the Roque-Haute Nature Reserve, Hérault (around 200 pools), for which it is difficult to sample all the pools in any one night. It only applies to relatively few species: mainly Stripeless Tree Frog, Green Frog, Parsley Frog and Natterjack Toad. • Counts of breeding adults: the method consists in counting the number of individuals present on a site. It is effective for

102

species in which breeding is brief but highly synchronised (Common Toad, Spadefoot) or for species which remain on the breeding site for a long time (Great Crested Newt). It is not suitable for species in which breeding is spread out over time (Parsley Frog, Stripeless Tree Frog) or in which the time spent on the breeding sites is very brief (Painted Frog, Parsley Frog). In all cases, the numbers of breeders present is underestimated. This method gives an idea of the size of the population and not an exact estimate. • Spawn count: the method consists in counting, by day or by night, the spawn deposited by the females. It can enable an excellent estimation of the population, or more precisely of the number of females using the site at any given moment. It can only be applied to a few species: essentially Parsley Frog and Agile Frog. The spawn must be easy to identify (a ball of eggs for the Agile Frog, cigar-shaped sleeve for the Parsley Frog) and deposited over a short period (several days). It cannot be applied to spawn in strings (genus Bufo, Spadefoot) or eggs that are laid separately (newts, Painted Frogs) or laid over too long a period of time. • Amphibian drift fence: This method consists in placing a fence around the pool, and traps (buckets or flowerpots) buried inside or outside the fence. Amphibians, especially adults, fall into the traps when arriving at or leaving the pool. A list of species is thus obtained as well as an estimate of the number of individuals using the site, the chronology of the arrivals/departures, and the direction taken. This is an effective method if the soil is fairly loose for the apparatus to be put in place. The method is not suitable for all species: the Stripeless Tree Frog Hyla meridionalis easily climbs over this kind of obstacle. Furthermore, its impact on the environment is not negligible, and the risks of predation and mortality are high in the captive animals, thus necessitating regular checks, at least every two days, and thus a major time investment. • Capture/marking/recapture (CMR)a consists in marking, during two sessions or more, all the individuals captured. Using the recapture rates, an estimate of the size of the population can be made by some simple calculations. This method presupposes a number of conditions which are rarely fulfilled in amphibian populations: no emigration-immigration, no mortality, equal probability of capture among individuals, etc. It also requires a thorough knowledge of the biology of the species if it is to be safely applied. Certain species (Spadefoot, Painted Frog) remain on the

Roché J.

minimum equipment and results which are comparable between sites. The method requires knowledge of identification of species at the larval/tadpole stage. It can have a considerable destructive impact on the vegetation (and on spawn).

Checking the traps around an amphibian drift fence (Roque-Haute)

6. Monitoring

breeding site for a very short time, with a high turnover from one evening to the next, which invalidates the method. In addition to an estimate of the population size, the technique enables information to be obtained about population dynamics, through individual life histories (see Demography below). Marking methods vary according to the species. Non-individual marking is often sufficient for an estimate of the population size. For this, several methods exist: photo-identification, marking with dyes, amputation of a digit, tattooing, installation of an electronic chip. Individual marking gives access to more information: individual survival with the aid of CMR techniques, site fidelity, etc. Photo-identification is possible in species with a complex ventral or dorsal design (salamanders, Great Crested and Marbled Newts, Yellow-bellied Toad, Spadefoots). It meets its limits when the population is large (larger than 200 individuals) because of the time needed for the recognition of the animal. Marking by electronic chip, implanted under the skin, is an alternative method, valid for all species of sufficient size.

In practice, allowing for exceptions, it is best to stick to measurements of size which separate only some age classes (first year, second year and adults, in most cases) but which can reveal major dysfunctions, such as an absence of recruitment over several years, for example. The various methods described are summarised in Table 21 and evaluated in terms of time, cost and level of knowledge required.

a. Experiments which mark individuals and skeletochronology* which require the amputation of a toe from an animal are not benign. They require preliminary requests for authorisation in which it is clearly stipulated that the animals will not be killed. In France, these requests should be presented to the DIREN, which forward them to the Ministère de l’Ecologie et du Développement Durable.

Demography Here, the aim is to find answers to precise questions, such as “Is the recruitment* in young individuals in the population sufficient to ensure its survival?” or “Is the population stable, in decline or increasing?” To reply to this type of question, the most appropriate method is CMR, which consists in studying what becomes of a representative sample of individuals over time (life history of individuals). An alternative method consists in analysing the structure of the population and its development over time. • Estimation of individual survival rates and the demographic trends of the population: from the technical point of view, the method consists in capturing an adequate sample of individuals (representatives of the population), marking them durably, and monitoring them over time. For the capture, one of the techniques previously mentioned is used (night captures on breeding sites, fences with traps, shelter traps, etc.). Individual marking makes use of the techniques mentioned above. The quality of the results will depend on several factors: the proportion of individuals marked in the population, the recapture rates of these individuals and the duration of the monitoring. To estimate the survival rate in any given year, a three-year monitoring programme is necessary (one year bracketed by two years); to estimate a trend, several years are necessary (the generation time of the species at least). It thus involves a technique that is time consuming and requires great rigour. It can only be applied in very specific conditions: a well-defined population in space and time, thorough knowledge of the biology of the species and the factors which can influence the survival of the animals. It is thus not a routine technique for a manager. • Demographic structure of the populations and cohort* monitoring: the method consists in estimating the relative importance of the different cohorts (years of birth or age classes) in the population. To identify the cohorts, measurements of the size or weight of the animals can be used (classes of size or weight) or their age estimated using the technique of skeletochronology* (see Jakob et al.199). This method is applied to a toe clipped from a living animal. It enables the annual growth layers to be read, as well as, in some cases, the birth line, which gives direct information about the age of the individual. As it is difficult to implement, skeletochronology is limited to authorised specialists and not really appropriate for monitoring purposes.

Table 21. Evaluation of amphibian-monitoring methods

Method

Objective

Time

Cost

Knowledge necessary

Night observation

Effectiveness of the technique

Inventory

*

*

*

*

Population size Demography

** -

* -

* -

* -

Auditory count

Inventory Population size Demography

* ** -

* * -

** ** -

** ** -

Pond net

Inventory Population size Demography

** -

* -

*** -

*** -

Inventory

*

***

***

**

Population size Demography

-

-

-

-

Amphibian drift fences Inventory Population size Demography

** *** ***

** ** **

* * **

*** ** ***

Inventory Population size

**

**

**

**

Demography

**

*

***

**

Inventory Population size

***

***

**

***

Demography

***

***

***

***

Larvae traps

Non-individual marking

Individual marking

* = low, ** = moderate, *** =significant

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Mediterranean temporary pools

e. Macrocrustacean monitoring

Methods

Thiéry A

Inventory

Unlike insects, invertebrates with exclusively branchial respiration (including branchiopod crustaceans) spend their entire life in a pool in two states: • an active state, in periods of flooding, during which they go through their biological cycle (growth, nutrition, reproduction, etc.) passing through the larval, juvenile and adult stages, • a diapause* state, in dry periods, during which the populations only survive in the form of resting eggs. When there is water in the pool, only a fraction of the population is active; the rest of the population can remain in the sediments in the form of eggs for several years. The ease of the direct observation in situ of an individual depends on the age of the organisms, and thus their stage of development and their size. Because of the synchronisation of the hatchings after flooding begins, all the eggs which have completed their diapause hatch in a few hours or days after submersion (dampening or rehydration alone of the sediments is ineffective). Individuals born on the same date will therefore develop as a cohort*, which facilitates the determination of the growth stages. During the first weeks of submersion, depending on the specific growth speeds (Fig. 43), only larvae or juveniles are found, which are difficult to observe and identify (small sizes, transparent).

a. The data collected will be put on a recording form destined to contribute to the national inventory initiated by the Museum National d’Histoire Naturelle in Paris and the Service du Patrimoine de Paris (model annexed to the second volume).

Figure 43. Speed of growth of macrocrustacean larvae (based on

Thiéry380) Tanymastigites jbiletica Triops granarius Cyzicus bucheti 45 40

Length (mm)

35 30 25 20 15 10 5 0 0

6

16

26

36

Time (days)

104

46

56

66

The inventorya is based on a series of qualitative samplings with a net with a mesh of 100 to 200 µm. The frequency of the samplings and their date will depend on the date and duration of submersion. For example, for a submersion in October and a drying-out in April, at least three samplings must be made: respectively 15 days, two-three months and three months after submersion. Samples are taken from different zones of the pool, in open water, among rooted or floating macrophytes, etc., to include all the different habitat subdivisions. In all cases, the samples are taken while taking into account the shadow made by the observer in sunny weather, as well as the wind which sends out shock waves due to the movements of the operator. Branchiopods are particularly sensitive to these disturbances and can rapidly escape. For identification, it is sometimes possible to photograph the individual in a crystallising dish, then release it. However, this work is more generally carried out at the laboratory after fixation in formalin diluted to 8-10% vol./vol. in water (70° alcohol sometimes causes excessive deformations, as well as the disappearance of colours through the dissolution of pigments). It is useful to note the particular colourations in vivo. Trapping techniques (nets, baits, underwater light traps, etc.) do not give conclusive results. An inventory of aquatic forms should be supplemented by a careful search for resistant forms during the dry phase. This method will be usually entrusted to a specialised and competent practitioner. Sampling should take place in various parts of the dry pool. Though rigorous methods have been described recently, including that of Maffei et al.246, for reasons of simplicity, we will retain the transect method (cf Chapter 6d) with: • sampling at the centre, at the deepest point (during the dry phase, female anostracans are able to gather together and release their eggs here), • sampling at the periphery, a little below the maximum water level (some eggs float and, under the influence of the winds, can accumulate on the banks, particularly under the prevailing wind). In Notostraca, the females of Triops have a marked tendency to agglutinate their eggs on gravel378, 385 while the females of Lepidurus stick them onto leaves or bury them partially in the sediments. In the case of Triops, the centrifugal egg laying (at the water’s edge) is an adaptation which enables the eggs to hatch only when the water level is at its highest: the duration of flooding will then be sufficient for the juveniles to reach maturity. Eggs are looked for by washing the sediments in a sieve with a 100-µm mesh or by flotation with water saturated in sugar or CaCl2 (method of separation by density difference). In addition, it is possible to look for macro-remains, i.e. fragments of strongly chitinised or keratinised cuticule (the mandibles of Lepidurus, telsons of Triops, antennae of Branchipus males, fragments of Spinicaudata carapace, for example, Fig. 44). This method has been tested with success in biotopes which have remained dry for several years in North and sub-Saharan Africa380. It is always useful to detail the conditions in which the species has been collected. The most important variables for crustaceans are mineralisation (measured by electrical conductivity), transparency, temperature, the dissolved oxygen concentration, the pH and the depth of the water380 (Chapter 3e). These measurements can be obtained by a research consultancy or university laboratory.

6. Monitoring

Population monitoring Monitoring the frequency, abundance and density of populations per litre or per unit surface area (m2) and the sex-ratio* is more time consuming and requires more rigour. In this case the pool is divided into numbered cells, some of which (at least 3) are randomly chosen for a sample (Latin Square technique) of known volume. The mean and variance enable the distribution of the species at time t to be established. For example, this protocol applied to Lindiriella massaliensis in the pool of Bonne Cougne (Var, France) has shown clumped individuals in December, then a random distribution in January, before the spontaneous disappearance of the population in February. In shallow water the samples are taken with a bottomless cylinder275, 375, 380. Sinking it a few centimetres into the sediment ensures that the base is watertight, which enables emptying or filtering of the water column, the volume of which is known (area of base x depth). When the depth exceeds 50-60 cm, a net is used, which filters a volume of water determined by the diameter of the opening and length of the sweep (1 or 2 m in general). The use of artificial substrates can supplement the usual methods (Box 56). Counting is done under a binocular microscope, and the counts are made either using absolute figures (juveniles, adults) or in the case of large numbers, using the Frontier151 method, which defines classes of abundance according to a geometric progression: • Mark 0 0 individuals, • Mark 1 1 to 3 individuals, • Mark 2 4 to 17 individuals, • Mark 3 18 to 80 individuals, • Mark 4 80 to 350 individuals, • Mark 5 351 to 1,500 individuals, etc. Determination of the sex-ratio is useful in the monitoring of populations, the ratio being susceptible to variations according to the species and the time scale. Techniques based on individual monitoring cannot be used with crustaceans: the moult does not allow for colour marking, and cutting off a cercus, or an amputation, as can be done with amphibians, results in the rapid death of the individual from haemorrhaging (open circulatory system). Other methods can be used for the study of macrocrustacean populations, but these are relatively burdensome to implement

and can require equipment which is rarely available to managers, as well as highly specialised technical skills. When they are necessary, these methods (described in summary below) can be implemented by specialist teams. Growth curves/life history tables require the establishment of correlations between the total length or the length of a body part, such as the telson, and the age of the individuals. Generally speaking, anostracans are measured from the front to the extremity of the cerci inclusive, notostracans by the length of the carapace and Spinicaudata by the length of the valves. The measurements are made on millimetre paper (rapid estimations) or with an ocular micrometer under a binocular microscope. Fecundity is measured by the number of eggs in each laying during the life of the female. By way of example, the number of eggs laid grows exponentially, from 2 to 350 per clutch, with the age of the female (8 to 17 mm). Knowing that she can lay between four and six times during her life, the number of eggs produced can be estimated as over 650. In the case of Spinicaudata (Cyzicus, Leptestheria, etc.), a female can lay several thousand eggs during her lifetime. Biomass measurements require a 10% formaldehyde fixation (does not deform and does not dissolve or only very slightly dissolves fats: 6 to 8% of biomass loss compared with 25% in alcohol), drying in a desiccator (65°C), cooling, then the weighing of individuals380 (singly or in lots of 10). The formulation of a specific regression equation Length (L mm) against dry weight (W mg) will serve for other habitats without having to repeat these operations. In the context of studies of metapopulations*, methods using a molecular tool (genetic structure of the populations, polymorphism of the loci, microsatellites, etc.) enable populations to be characterised (intra-site stability) and their isolation, or their interpopulation relations within an ensemble of sites constituting a fragmented range, to be quantified (see Bohonak39 and Brendonck et al.57, for examples in Anostraca).

Figure 44. Remains of macrocrustaceans found in sediment (based on Thiéry380) A, B. Anostracan: antenna of Branchipus schaefferi and Tanymastigites jbiletica C, D, E. Fragments of cerca of cephalo-thoracic shield, mandibule of Triops granarius F. Concostraca: fragment of pincers of Leptestheria mayeti

A

C

D

F

E

B

105

Mediterranean temporary pools

f. Insect monitoring

Box 56. A new method of sampling in a still water habitat

Thiéry A.

Inventory The methods described for macrocrustaceans are also valid for insects. However, for the inventory of a biotope, the method of night hunts with a UV lamp against a white sheet can be added. This type of trap is particularly effective at the beginning of the summer, a period in which many insects metamorphose. The search for exuviae, as in the case of dragonflies (Odonata), will also be very useful163 for the inventory. Adults may also be marked to estimate numbers using the capturerecapture method (De Lury in Lamotte & Bourlière219), as has been done for aquatic dytiscid Coleoptera104. The inventory can be semi-quantitative. The classification proposed below165 distinguishes five groups: fundamental, constant, associated, incidental and occasional species. These groups are defined using all the samples by the relative abundance of the species (Ar = number of individuals of the species a x 100/number total of individuals collected) and their frequency (F = number of samplings where the species a is present x 100/number total of samplings): • Fundamental: F > 50% and Ar > 10%, • Constant: F > 50% and Ar <10%, • Associated: 20
Although for running-water habitats, standardised tools have been developed to sample and characterise the faunistic assemblage, still water habitats do not have methods enabling evaluation of their diversity or monitoring of their changes over time (in response to management operations at pools, for example). For several years now, tests of artificial substrates acting as substrates for colonisation have taken place, which will enable the abundances of insects to be standardised371. They are made from natural, (gravel, wood, litter, etc.) or artificial (tiles, bricks, plastic plants, etc.) materials. This method, which is being developed (Scher & Thiéry, com. pers.) at temporary pools associated with motorways, is based on the use of standard artificial substrates (plastic aquarium plants, brushes, bath sponges, etc.). Initial results have shown that, for the majority of taxa, a minimum duration of exposure of three weeks is necessary. They show that different invertebrates are attracted depending on the substrate and their mode of life (Tab. 22). Oligochaetes, benthic burrowing organisms, are dominant in the “brush” substrate, while the swimming larvae of zygopteran Odonates and the ephemeropteran Cloeon prefer to colonise substrates in open water. Similar results are noted for the trapping of the larvae of Chironomidae and ostracod crustaceans. The use of artificial substrates enables the impacts of management on shallow still habitats to be qualified, and presents advantages in terms of cost, standardisation, repeatability and ease of use. Scher O. & A. Thiéry

Table 22. Differential attraction of invertebrates in relation to various artificial substrates

Type of substrate Brush Scrapers (benthic) (pelagic) 595 14 8929 2319

Ephemeroptera

min max

13 63

15 60

24 143

Odonata

min max

15 35

3 27

5 186

Chironomidae

min max

19 107

60 298

48 286

Ostracoda

min max

11 100

21 354

124 1981

106

Scher O.

min max

Density per litre

Oligochaetes

plant (mixted) 63 379

A method of sampling invertebrates: the installation of artificial substrates as colonising aids

7. Education and communication Genthon S. Mediterranean temporary wetlands are gradually disappearing and there is usually general indifference to this, as the general public has a poor understanding and knowledge of these habitats. Informing and raising the awareness of those who will have an impact on their future is thus essential.

Communication: bringing temporary pools and their riches to the attention of the public Legislative protection and habitat management are not in themselves sufficient to protect temporary pools. Informing and raising the awareness of the public is essential, not only to prevent pollution and degradation, but also so that the richness of these pools can be taken into account with regard to physical planning. Improving knowledge of temporary pools and demonstrating the value of managing them to a wider public will help to ensure that these wetlands enjoy lasting protection.

Communication Strategy The diversity of stake-holders in these habitats makes it essential that prior discussion takes place regarding the identification of the target public and the establishment of a proper strategy to inform users and modify their behaviour. In addition to information, this also means involving the public in the protection of temporary pools through concrete actions on the ground or local events. Communication will be effective if a study of the use of the site by the public is carried out in advance. It enables the needs and expectations of each identified public user group to be known. The choice of communication supports results from these needs as well as the objectives fixed by the manager (Tab. 23). The framework tool is the communication plan which defines objectives and plans awareness-raising operations over several years (three to five years). It can be integrated into the management plan of the site. The objectives of public awareness-raising often take the involvement of local populations into account. It is they who have an immediate impact on the protection of the temporary pools in their area.

To inform and involve the public, managers have several tools available, some of which have been produced within the framework of the LIFE “Temporary Pools” project (Box 57): • for local populations: programmes of events and visits, information panels, reception infrastructure, exhibitions, nature festivals and other local events, etc. • for elected representatives and decision-makers: brochures, leaflets, videos, site visits, inauguration of local events, information campaigns, etc. • for children and young people: educational trips, events in schools, reception of trainees and training, etc. • for the general public: nature workshops, events, information bulletin, brochures, leaflets, Internet site, videos, features in the media (local newspapers, TV), etc. • for the media: communiqués and press packs, invitation to events, etc. • for scientists and managers: information bulletin, annual report of activities, Internet site, etc. Tools for the general public can, of course, be used for all other specific public groups.

Some tools which have proved their worth Nature workshops are good ways of involving the public in the protection of temporary pools, by providing information about conservation issues. In this way volunteers participate concretely in the conservation of their natural heritage50. The regular organisation of local events keeps the population informed: nature festival, exhibitions, slide shows, conferences, art competitions in schools, etc. Guided visits help a wide public find out about temporary pools in the field. The information documents should be comprehensive, illustrated and practical: leaflets, information bulletins, annual reports of activities, etc. Their effectiveness also depends on their distribution, which should be planned in advance. Multimedia (Internet) enables a wide diffusion of information, but it is especially useful in helping to put those involved into a network. The effectiveness of information and events is even greater if awareness-raising initiatives are made in partnership with local players and/or through networks in which the manager participates. Regular events organised around temporary pools enable more and more people to become interested in the protection of these habitats.

The public and information tools

Environmental education: pools are good teaching aids

In most cases, the manager should provide information to the following: • town and country planners, farmers/livestock rearers, etc., likely to inadvertently destroy pools through modifications in their hydrology or by public works (urbanisation, the fire fighting services, tracks and roads, etc.), • walkers (numerous problems linked to the over-frequentation of sites), • decision-makers and elected representatives responsible for the planning and development of their territories and local policies, • the media which diffuse information, • children and young people, future players in the management of temporary pools (see paragraph 2), • owners of sites and their surroundings.

Children particularly appreciate temporary pools which are ecosystems on their scale. Carrying out educational activities around a temporary pool becomes almost “child’s play”. Through nature trips and environmental education projects, young people acquire a naturalists’ knowledge of the habitat, increasing their understanding of how it functions and enabling them to take part in discussion on the protection of the pools. A sensitive and imaginative approach is also important for creating an emotional link with the natural environment, which will influence the behaviour of the future. Children also help to raise awareness among their parents. Temporary pools are also good teaching aids for passing on expertise, notably of techniques of nature observation and the use of observation equipment (methodological objective).

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Mediterranean temporary pools

Table 23. Publication choices for the Roque-Haute Nature Reserve (AGRN.RH - Hérault)

Mid-term objectives (driven from the management plan)

Target public

Which document?

1. Introduce the Reserve and raise awareness among the public, in particular young people, of nature protection

Schools

- comic strips - nature books and educational tools

General public

- information and interpretation panels - Educational notes

2. Increase awareness-raising of the local population - travelling exhibition - nature workshops - open days - occasional evening events (slide show, etc.) - contact with local media - consultation of local population - involvement in local nature events

Local population, Reserve users, elected representatives and tourists, etc.

- information stand and floral exhibition - documents for the general public (see objective n°3)

3. Provide information about the Reserve and enhance its policy of management and protection among different publics by - information documents, multimedia (Internet) - regional, (nature, environment festivals, etc.) or national events (fairs, salons, etc.), relations with the media, World Wetlands Day

General public

- leaflets, brochures, themed information sheets (archaeology, etc.)

(Reception of visitors, programmes of events and educational modules)

- Internet site (http://roque.haute.free.fr) - information stand, posters and promotional documents

Partners

- annual report of activities

Partners and general public

- Newsletter from Roque-Haute - Reserve information bulletin

Media

- communiqués, press packs, etc.

4. Pursue the involvement of the Reserve in professional networks (Cooperation, exchanges of expertise and experiences in the management of natural habitats and environmental education) Example 1: LIFE “Temporary Pools” project

General public, decision-makers

- Leaflets, information panels, video on temporary pools

Example 2: Network of protected natural spaces in Languedoc-Roussillon

Managers of natural areas and partners

- Newsletter of Regional Network (information bulletin)

5. Promote scientific research on the Reserve

Researchers, naturalists and scientists

- proceedings of the 1998 symposium (Periodical Ecologia Mediterranea)

108

7. Education and communication

Box 57. Main achievements of the “awareness raising” section of the LIFE “Temporary Pools” project The LIFE “Temporary Pools” project (1999-2004) has enabled a range of information tools to be produced common to the three regions of southern France: Corsica, Languedoc-Roussillon and PACA: Brochures and leaflets were widely distributed during the awareness-raising campaign among decision-makers and elected representatives (mailing) and the national information campaign. The onsite information panels raise the profile of the local natural heritage; they are supplemented at one of the sites (Plaine des Maures) by a travelling exhibition which will circulate in the various communes concerned. An educational module delivers practical advice and information to teachers and animators so they can organise educational projects around temporary pools. The events organised for European Green Days or local nature festivals help raise awareness among very varied sections of the public. They are very effective in involving local populations. Regular contact with the media contributes to a broad diffusion of information, both at local level during, events or activities, and at national level, for press campaigns. It is important to regularly inform the media. A “Temporary Pools” discussion forum enables data to be exchanged and experiences to be shared regarding both environmental education and the management of pools. This new network of players has been developed thanks to the Internet: http://fr.groups.yahoo.com/group/mares_temporaires. A TV documentary on Languedoc-Roussillon was made in 2001. This video has been distributed to resource centres (libraries, etc.) and decision-makers. It has been used for regional events and during the campaigns of awareness raising among elected representatives, to obtain support for projects for the protection and management of temporary pools. This 12-minute long film presents a portrait of several temporary pools in Languedoc-Roussillon, their natural richness, the threats they face and initiatives to protect them.

Training/Cooperation: exchanging experiences and being involved in networks of players The involvement of the manager in regional (GRAINE, CPN, etc.), national (ATEN, Réserves Naturelles de France, Espaces Naturels de France, etc.), or even international, networks enables the technical and sometimes financial means to be obtained to carry out awareness-raising initiatives. It also ensures that a wider public is reached and is a means of exchanging experiences. The development of common tools helps to create common terms of reference and raise awareness among those involved in environmental education (teachers, animators, trainers etc.). In addition, as the production of communication aids is often costly, it can be useful for smaller establishments to produce common tools in order to share the costs. Above all, working within a network enables teaching methods to be exchanged and encourages local institutions/organisations (schools, universities, associations, etc.) to get involved with their local sites. All these actions contribute to better integration of the natural area into the local socio-cultural fabric. Local protagonists will be all the more ready to help with the protection of temporary pools if the site becomes an integral part of local life. The LIFE “Temporary Pools” project has built up a preliminary network of animators and technicians who are involved with temporary pools following a common training programme. A seminar designed to develop events around temporary pools in 2001 brought together for the first time managers and events organisers to

These tools have reinforced the awareness raising initiatives already carried out locally before this project (reception of visitors, activities, educational events, etc.).

The “Temporary Pools” educational module, produced within the context of the LIFE “Temporary Pools” project, thus offers teachers and animators practical tools for organising events around these habitats. The framework tool which enables environmental education to be developed around temporary pools is the interpretation plan59. It provides a list of resources, analyses the educational potentials of the natural area and defines what can be exploited, depending on the fragility of the habitat and the organisational constraints (duration, interest, etc.). It also helps in prioritising objectives and selecting target publics. The educational initiatives are always carried out in accordance with the priority conservation objectives of the natural heritage of a site.

Corbineau N.

Genthon S.

Educational visit to the Roque-Haute pool: measuring the water temperature

109

Mediterranean temporary pools

In conclusion, environmental communication and education, and the involvement of the manager in professional networks, contributes to furthering knowledge of Mediterranean temporary pools and thus to their protection. It is a long-term investment, designed to change behaviour and to integrate these wetlands into local planning and development.

Roché J.

share their experiences with regard to wetlands events, and discuss events which could be transferred to other sites. An Internet forum, the “Temporary Pools Club” enables exchanges to be made and educational tools to be put online (http://fr.groups.yahoo.com/ group/mares_temporaires). The educational module produced by this LIFE “Temporary Pools” project is the culmination of this capitalisation of a variety of experiences.

A visit by experts from the LIFE “Temporary Pools” project to the Plaine des Maures

110

Glossary

Genotype: the ensemble of genetic characters possessed and

transmitted by an organism. Geophyte: plant species which withstand the unfavourable seaAggradation: Situation resulting from gradual infilling by accu-

mulated material (soil, silt, sand, gravel, etc.). Allopatric speciation: formation of a new species which occurs when two populations are separated by a biogeographical barrier preventing interchanges of genes (= as opposed to sympatric speciation, without geographical isolation). Anemochory: mechanism of dispersal of seeds, spores, eggs etc. of certain animal and plant species by the wind. Angiosperms: flowering plants whose ovules are contained within a closed cavity, or ovary. Includes the majority of large and medium-sized terrestrial plants. Anoxia: refers to the absence of oxygen in the environment. Autogamy: (= self-fertilization) mode of sexual reproduction resulting from the union of two gametes (male and female) produced by the same individual animal or the same flower. Biocenosis: set of living organisms, animal and plant, occupying the same biotope. Biogeography: branch of biology dealing with the geographical distribution of plants and animals. Bryophytes: group comprising both mosses and liverworts. Charophytes: specialised algal group consisting of one family, the Characeae, characterised by the whorled structure of the thallus and by the highly complex structure of the reproductive organs (antheridia and oogonia). Cohort: set of individuals which have experienced the same event at the same time (individuals born at the same time or breeding at the same time in pools, for example). Connectivity: Facilitation of the movement of individuals of a species between local sub-populations to form a single functional demographic unit. Diapause: period during which metabolic activity and the development of an insect is suspended at a particular stage (egg, larva, nymph or adult), as a result of the action of internal or external factors. Dormancy: temporary physiological state among certain plant organs, characterised by reduced metabolism and triggered by unfavourable external conditions. Only ad hoc microclimatic or physiological conditions can bring this state to an end by breaking dormancy. Ecophase: during its life cycle, a species passes through different stages (egg, larva, juvenile. etc.). An ecophase corresponds to one of these stages having a different ecology from the other parts of the cycle. Electrical conductivity of water: simple measurement of the concentration of ions in the water; conductivity, measured in Siemens, is the opposite of electrical resistance. Endemic: used of a species exclusively confined to a given biogeographical area, often of limited extent. Endorheic: refers to lacustrine biotopes (lakes, pools, etc.) which are situated in the floors of closed continental basins which are therefore lacking in outlets. Ephemerophyte: used of a plant with a very brief vegetative cycle. Foliaceous appendage: arthropod appendage, enlarged in the shape of a leaf, playing a role in the trapping and filtering of food particles, and in respiration among crustaceans. Freshwater: used to describe organisms that live only in fresh water. Gemmiform: bud-shaped.

son thanks to the presence of bulbs, rhizomes or any other type of underground reserve organ (see glossary, vol. 2). Generalist: refers to species which are capable of colonising a wide range of habitats and as a result often have a very wide geographical distribution. Genetic bottleneck: sudden decrease in the size of a population associated with a decrease in the total genetic variability. Gyrogonites: calcified female fructifications produced by charophytes, corresponding to fossil or living forms after dispersal. They are invariably made up of five cells in the form of lefthanded spirals, joined at the tips. Heliophilous: used of a plant which grows in conditions of strong sunlight. Helophyte: marsh plant whose budding parts, which enable it to survive during the bad season, are laid down in the sediment, while in the good season they develop an aerial structure which extends above the water surface (Reed, for example). Hemicryptophyte: perennial herbaceous plant whose budding parts, which enable it to survive during the bad season, remain on the surface of the soil, at the very base of the stems (or of the tuft for caespitose Graminae) (see glossary, vol. 2). Hydroperiod: period during the year when the pool contains water. Hydrophyte: plant that lives in an aquatic environment (Water Milfoils, Water Lilies). Hygrophilous: organisms dependent on biotopes characterised by high soil water content. Inbreeding depression: interbreeding by closely related parents leading to the production of individuals of poorer quality. Life-history traits: significant characteristics of the life cycle through which an organism passes and more particularly those associated with strategies for survival and reproduction. Mesohygrophilous: organisms dependent on biotopes characterised by medium soil water content. Metapopulation: Set of populations that are interconnected via migration events (gene flow) and are subject to extinction and recolonisation. This concept may be extended to include any set of populations developing in a more or less independent way which are, however, interconnected through rare instances of migration. Minimum effective number: number of actually reproductive individuals in a population at a given time. This number will always be less than the number of individuals present in the population, since a proportion of the individuals will not be reproductive (senility, absence of mates, harem formation, etc.). Nutrient: simple substance which is capable of being assimilated by an organism without being broken down by digestion (for example phosphate, nitrate, etc.). Oligotrophic: describes nutrient-poor water (low in nitrate, phosphate, sulphate): its opposite is “eutrophic”. Oospore: Female fructification found in charophytes, formed from a spore with a resistant shell. Pioneer: individual or species which establishes itself at an uninhabited site, for example following disturbance. Poikilotherm: describes an animal whose body temperature varies with the temperature of the environment where it lives (reptiles, insects or crustaceans, for example). Propagule: any part of an organism, produced by asexual or sexual reproduction, capable of producing a new individual.

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Quiescent: state of temporary suspension of development of an invertebrate triggered by unfavourable ecological conditions such as drought. Release from quiescence takes place immediately after the return of favourable conditions. Recruitment: the adding of new individuals to a population. Recruitment takes place through reproduction, immigration and restocking. Rhizoid: hair-like rooting structure, particularly among mosses. Sessile: Botanical: an organ (leaf, flower) having no petiole or peduncle. Zoological: microorganism attached to a support (stem, rock, etc.). Sex-ratio: ratio of the numbers of male and female individuals in a defined population. Skeletochronology: method of determining the age of a vertebrate (amphibian in this work) by counting the growth lines visible in cross-sections of the phalanges or the humerus.

112

Stripping: action consisting in removing the overlying layer or

the root mat. Therophyte: synonym for an annual plant, a herbaceous plant

with a very short reproductive cycle, lasting a few months or in certain cases a few weeks, which survives the bad season in the form of seeds. (see drawing by Raunkiaer, vol. 2). Trophic: everything relating to nutrition among plants and animals. Tuberiform: tuber-shaped. Vegetative reproduction: mode of reproduction of a plant species using vegetative organs (stolons, rhizomes, tubers, etc.). Vicariant: used of animal or plant species that are taxonomically closely related and which inhabit environments with similar ecological characteristics in different geographical regions. Water-level range: distance between the lowest and highest water levels of a body of water.

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