Phase 3 - Science Report Final
This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA
Overview
Download & View Phase 3 - Science Report Final as PDF for free.
More details
- Words: 13,623
- Pages: 54
Global Vision International Costa Rica Phase 3 Report (16th January – 27th March 2006)
Britt M. Larsen, Nicole Evans, Lydia Chaparro and James P. Lewis
1.
EXECUTIVE SUMMARY
The third 10-week phase of the Costa Rican Global Vision International (GVI) Expedition has now been completed. The expedition has continued to gather important environmental scientific data whilst working with local, national and international partners. The expedition has also maintained working relationships with local communities through both English classes and Inter-cambio. The following projects have been run during phase 3: I.
Jaguar predation on sea turtles. In collaboration with the Costa Rica Ministry of Environment and Energy (MINAE);
II. Marine Turtle Monitoring Programme (collaboration with the Canadian Organization for Tropical Education and Rainforest Conservation (COTERC), MINAE and the Caribbean Conservation Corporation (CCC)); III. EBCP Resident Bird Project (collaboration with Steven Furino, Waterloo University, Canada); IV. Tourist impact assessment within the Tortuguero National Park; V. English language lessons (collaboration with the San Francisco community); and VI. Inter-cambio with staff from Cabinas Vista al Mar and the Tortuguero National Park staff at Cuatro Esquinas. GVI has initiated an additional preliminary study during phase 3: VII. Tourist impact assessment on Caño Palma canal in addition to and in comparison with the tourist impact assessment conducted in Tortuguero National Park.
i
1.1.
Introduction
The Coastal Rainforest Conservation Expedition at the Biological Station Caño Palma in Tortuguero, Costa Rica has now completed its third phase (3 x 10 weeks). The expedition to date has assisted in collecting a substantial amount of scientific data. Although this data is already helping to identify potential future research areas and providing important data to the international scientific community it is still at the preliminary stage. Methodologies continue to be improved and focused as experience is gained and improvement to data quality is continuous. A full Annual Report in December 2006 will collate and summarize all data and enable more descriptive and accurate analysis. The main aim of the GVI projects established with MINAE is to collect raw data, which will then be handed over to MINAE for collation, analysis and comparison with other relevant data.
Acknowledgements This report is successful due to the hard work of all Expedition Members who took part in this third phase of the Costa Rican Rainforest and Wildlife Expedition: Andrew Metcalfe Joanna Miller Amie Smith Ben Stubbens Nadia Gergova Jennifer Smith Tracy Keyte
Alyssa Mummert Melissa Martin Derek Harder Sally-Ann Haw Clayton Bostock Helen Smith Kelsey Doods
Julie Jackson Karen Donnor Jayne Elliott Gabriela Mora Camac Holly Guest Alan Collins
We also thank our partners COTERC, MINAE, ACTo, Steven Furino, and San Francisco community for all their help and support.
ii
Contents 1.
EXECUTIVE SUMMARY .......................................................................................i 1.1.
2.
3.
Introduction................................................................................................... ii
JAGUAR PREDATION ON MARINE TURTLES...................................................1 2.1.
Introduction...................................................................................................1
2.2.
Aim ...............................................................................................................1
2.3.
Methodology .................................................................................................1
2.4.
Results .........................................................................................................2
2.5.
Discussion ....................................................................................................3
MARINE TURTLE MONITORING PROGRAMME................................................6 3.1.
Introduction...................................................................................................6
3.2.
Aim ...............................................................................................................7
3.3.
Methodology .................................................................................................7
3.3.1.
Track and Nest Surveys .......................................................................7
3.3.2.
Night surveys........................................................................................8
3.3.3.
Tagging.................................................................................................8
3.3.4.
Biometric Data ......................................................................................8
3.3.5.
Human impact data ..............................................................................9
3.4.
Results .........................................................................................................9
3.4.1.
Track census and nest surveys ............................................................9
3.4.2.
Monitoring of nests .............................................................................10
iii
3.4.3.
Monitoring of female turtles ................................................................10
3.4.4.
Tagging...............................................................................................11
3.4.5.
Biometry of female turtles...................................................................11
3.4.6.
Human impact data ............................................................................11
3.5.
4.
3.5.1.
Track census and nest surveys ..........................................................12
3.5.2.
Monitoring of nests .............................................................................12
3.5.3.
Tagging and monitoring of female turtles ...........................................13
3.5.4.
Biometry of female turtles...................................................................13
EBCP RESIDENT BIRD PROJECT....................................................................13 4.1.
Introduction.................................................................................................13
4.2.
Aim .............................................................................................................13
4.3.
Method .......................................................................................................14
4.3.1.
Point Count Method............................................................................14
4.3.2.
Area Search Method...........................................................................15
4.4.
Results .......................................................................................................16
4.4.1.
Point Count Results............................................................................17
4.4.2.
Area Search Results...........................................................................19
4.5. 5.
Discussion ..................................................................................................12
Discussion ..................................................................................................22
NATIONAL PARK TOURIST IMPACT ASSESSMENT ......................................23 5.1.
Introduction.................................................................................................23
iv
5.2.
Aims ...........................................................................................................24
5.3.
Methods......................................................................................................24
5.3.1.
Aquatic Trails......................................................................................25
5.3.2.
Terrestrial Trail ...................................................................................26
5.3.3.
Strawberry Poison Dart Frog (Dendrobates pumilio) transects ..........26
5.4.
5.4.1.
Aquatic Trails......................................................................................27
5.4.2.
Terrestrial Trail ...................................................................................31
5.4.3.
Strawberry Poison Dart Frog (Dendrobates pumilio) Transects .........31
5.5.
6.
Results .......................................................................................................27
Discussion ..................................................................................................31
5.5.1.
Aquatic Trails......................................................................................32
5.5.2.
Terrestrial Trails..................................................................................33
5.5.3.
Strawberry Poison Dart Frog Transects .............................................33
TOURIST IMPACT SURVEY CAÑO PALMA .....................................................33 6.1.
Introduction.................................................................................................33
6.2.
Aims ...........................................................................................................34
6.3.
Methods......................................................................................................34
6.3.1.
Aquatic Trails......................................................................................34
6.3.2.
Boat Dock Survey...............................................................................35
6.4.
Results .......................................................................................................35
6.4.1.
Aquatic Trails......................................................................................35
v
6.4.2. 6.5.
7.
Boat Dock Survey...............................................................................37
Discussion ..................................................................................................37
6.5.1.
Aquatic Trails......................................................................................37
6.5.2.
Boat Dock Survey...............................................................................38
COMMUNITY WORK..........................................................................................39 7.1.
Introduction.................................................................................................39
7.2.
Aims ...........................................................................................................39
7.3.
Method .......................................................................................................39
7.4.
Results .......................................................................................................40
7.5.
Discussion ..................................................................................................40
8.
SUMMARY CONCLUSION.................................................................................41
9.
Bibliography ........................................................................................................43
vi
Tables Table 3-1. Number of Monel tags, Details of previous and recent tags and measurements of carapace lenght and width from the turtles encountered during nesting on the North Beach, Tortuguero 2006. ..........................................................11 Table 4-1 Data collected during Point Count surveys ................................................15 Table 4-2 Data collected during Area Searches ........................................................15 Table 4-3 Species composition of birds, recorded during both Point Counts and Area Searches, based on abundance within the Tortuguero area .....................................16 Table 4-4 Species composition of birds, recorded during Point Counts, based on abundance within the Tortuguero area ......................................................................17 Table 4-5 Species composition of birds, recorded during Area Searches, based on abundance within the Tortuguero area ......................................................................19 Table 5-1 Comparison of the six most common bird species found within the different study areas.................................................................................................................29 Figures Figure 2-1 Beach distribution of Jaguar and turtle track along the 14.5 miles in Tortuguero National Park. Period: 3 February – 22 March 2006……………………….3 Figure 2-2 Date distribution of tracks (Jaguar and Turtles) and turtle carcasses in Tortuguero
National
Park.
Period:
3
February
–
22
March
2006.…………………………………………………………………………………………..4 Figure 3-1 and Figure 3-2 Temporal and spatial nesting distribution of total tracks (nests and half moons) for Leatherbacks (Dermochelys coriacea) on the North Beach during the first month of the nesting season in 2006. ................................................10 Figure 4-1 Species composition of birds, recorded during Point Counts, based on abundance within the Tortuguero area ......................................................................16 Figure 4-2 Species composition of birds, recorded during Point Counts, based on abundance within the Tortuguero area ......................................................................17 vii
Figure 4-3 Variation between number of birds and frequency of records during Point Counts........................................................................................................................18 Figure 4-4 Variation in identification of species and comparison between seen and heard recordings during Point Counts........................................................................19 Figure 4-5 Species composition of birds, recorded during Area Searches, based on abundance within the Tortuguero area ......................................................................20 Figure 4-6 Variation between number of birds and frequency of records during Area Searches. ...................................................................................................................20 Figure 4-7 Variation in identification of species and comparison between seen and heard recordings during Area Searches. ...................................................................21 Figure 5-1 Data categories for aquatic survey. ..........................................................25 Figure 5-2 Mean percentage difference for combined mean percentage difference for time, number of records and number of birds ............................................................28 Figure 5-3 Quantity of the top six non-avian species recorded during aquatic surveys ...................................................................................................................................30 Figure 5-4 Distribution of non-avian species within Aquatic Study site......................30 Figure 5-5 Number of individuals recorded per trail sector ........................................31 Figure 6-1 Data categories for aquatic survey ...........................................................34 Figure 6-2 Comparison of mean average data from National Park and Caño Palma 36 Figure 6-3 Top 6 avian species recorded on Caño Palma.........................................36
Appendix Appendix 1. GVI Costa Rica Key Avian Species List…………………………………..44
viii
2.
JAGUAR PREDATION ON MARINE TURTLES
2.1.
Introduction
Marine turtle predation by Jaguars (Panthera onca) seems to have increased within the past 10 years in Tortuguero National Park (Troëng, 2000; Magally Castro, pers. comm.). In 1998 a minimum of 25 Green Turtles (Chelonia mydas) were killed by Jaguars in Tortuguero National Park and several sightings occurred in the late 1990’s (Troëng, 2000). Although there is not much evidence of this atypical foraging behaviour, documentation exists from Suriname, where 82 Green Turtles were killed in the period 1963-1973 (Autar, 1994) and French Guiana (Troëng, 2000). Data has also been collated from the Pacific Coast of Costa Rica, where Jaguars prey upon Olive Ridleys (Lepidochelys olivacea), Black (Chelonia agassizii) and Hawksbill Turtles (Eretmochelys imbricata) (Troëng, 2000). Due to lack of human resources the Costa Rican Ministry of Environment and Energy (MINAE) invited GVI to continue data collection on Jaguar presence and predation of marine turtles in Tortuguero National Park. Data collection has now been conducted by GVI since 11 July 2005, and together with the existing sets of data collected by MINAE, it will aid in their future analysis in order to use as a tool for further management of Jaguars, turtles and their habitat in Tortuguero National Park. 2.2.
Aim
The Jaguar project aims to document the presence of Jaguars (Panthera onca) on the beach of Tortuguero National Park and their predation of nesting marine turtles. Data collection from this season will be compared with the previous year’s collected data and added to the long-term monitoring of Jaguar predation on marine turtles in Tortuguero National Park. 2.3.
Methodology
Jaguar walks are conducted over the 14½ mile stretch of beach from the entrance of Tortuguero National Park (mile 3½) south to Jalova lagoon (mile 18). One to two GVI staff member and three to five Expedition Members conduct the survey once per week, starting from either Tortuguero or Jalova at dawn. General data such as date, name of researchers, weather, sand condition and start time is noted at the beginning of the survey. Beach size (distance from vegetation to high tide mark) is recorded every four miles (at mile 4, 8, 12 and 16) to give an indication of how much 1
beach was exposed during the previous night. Sand condition and general weather are also recorded every four miles. During the survey, researchers count the total number of fresh (1-2 nights old) turtle tracks on the beach, including both half moons (not nested) and full tracks (nested). When Jaguar tracks are encountered, the right hind foot is photographed and the length and width of the track are measured. The direction of the track (north or south) and location (mile marker and GPS coordinates) are also recorded. The track is then followed until it ends (goes into the vegetation or is washed away by the tide) and the mile marker and GPS coordinates are recorded again. As would be expected intense and prolonged rain, high winds and very dry sand, can reduce the quality of Jaguar prints making data collection very difficult. As weather conditions vary throughout the year it is possible data quality will be affected. In order to minimise this Jaguar surveys are undertaken during and after periods of optimal weather conditions where possible. Data on fresh carcasses of turtles killed by Jaguars is collected where possible. Data includes location (mile marker and GPS coordinates), species, point of attack, nights since kill, amount of meat eaten, location of carcass relative to the vegetation, whether the turtle is on its front or back, and any extra comments/observations. Photographs of particular features may be taken. 2.4.
Results
A total of 7 full surveys 1 were conducted between 3 February and 22 March 2006, with an average time of 9 hours and 20 minutes. A total of 31 surveys have been conducted by GVI since 11 July 2005. During Phase 3, two Green Turtles (Chelonia mydas) were killed by Jaguars (8 March and 22 March 2006). The number of separate sets of Jaguar tracks found during this phase was 39. A total of 67 Green tracks (full tracks 2: n = 37 and half moons: n = 30) and 21 Leatherbacks tracks (full tracks: n = 19 and half moons: n = 2) was recorded. The distribution of turtle and Jaguar tracks per mile and the location of the two turtle carcasses are shown in figure 2.1.
1
The total number of surveys was 8, but one (1) was aborted.
2
One ascending and one descending track independent of nest information; attempted nest or nest.
2
# 30 25 20 15 10 5 0 4 4/8
5
5 4/8
6
6 4/8
7
7 4/8
8
8 4/8
9
9 10 10 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 4/8 4/8 4/8 4/8 4/8 4/8 4/8 4/8 4/8
# jaguar set of tracks
Mile
# turtles tracks
Figure 2-1 Beach distribution of Jaguar and turtle track along the 14.5 miles in Tortuguero National Park. Period: 3 February – 22 March 2006. The symbol (
) represents the location of the
two turtle carcasses found during this period
In this phase, the highest concentration (more than 15 sets of tracks) of Jaguar tracks was between mile 7 and 13. The overall distribution of tracks and carcasses in
#
relation to date of survey is shown in figure 1.2.
70 60 50 40 30 20 10 0 3-feb
10-feb
17-feb
24-feb
Jaguar tracks
3-mar
10-mar
17-mar
Turtles tracks
Figure 2-2 Date distribution of tracks (Jaguar and Turtles) and turtle carcasses in Tortuguero National Park. Period: 3 February – 22 March 2006. The symbol (
) represents the date of the
two turtle carcasses found during this period (8 March and 22 March 2006)
2.5.
Discussion
Data collection during Phase 3 incorporates off season data (January and February) for Green and Leatherback Turtles and the beginning of the nesting season (March to July) for Leatherback Turtles. This information gives us a good picture of Jaguar
3
Date
presence on the beach of Tortuguero National Park during non-nesting and low density nesting periods. The presence of Jaguar tracks was registered in all the surveys. However, due to heavy rain washing out the tracks in the days before the survey, no data was collected on the size of tracks during the last survey on 22 March. The presence of tracks were recorded from mile 4 to 17 4/8, with an important concentration from mile 4 to 17 4/8 and in particular there seem to be two areas with a higher concentration from 7 4/8 to 8 and from mile 9 to 11. The two turtle carcasses located around mile 11 and mile 13 2/8 were found in the area of highest concentration of Jaguar tracks (> 15 sets of tracks). During Phase 3 there was evidence of Jaguar presence from all beach surveys. It therefore seems to indicate that Jaguars include this habitat in their home range during turtle non-nesting season and indeed most of the year (based on data collected by GVI since July 2005). Although the Green Turtle nesting seasons is recognised to begin on the 1st of June a few turtles came up the beach to lay eggs before this date (full tracks, n = 37). Two Green Turtles were recorded as being killed by Jaguars during Phase 3. It should be acknowledged however that although the Green Turtles came on to the beach outside of their nesting period it did fall within the nesting period of Leatherback Turltes. Currently there is insufficient data to support the theory that Jaguars’ foraging behaviour is directly correlated to marine turtle nesting seasons. Further long term research will help to identify any correlation that may be present and may possibly identify if there is an adaptive behavioural trait within the jaguar population, relating to turtles nesting. There are several hypotheses for jaguar presence on the beach, these include an increase in the jaguar population, deforestation forcing jaguars out on the beach and the decline in other prey species. At present none of the hypothesis can be supported or disproved (Troëng, 2000). The current method being used by GVI to distinguish between Jaguar prints involves comparison of print width and length. This method however is not ideal as track sizes can be statistically similar based on these two characteristics alone. Computer analysis of tracks enables up to 48 different measurements to be taken from each print. This increases significantly the statistical confidence with which it can be assumed a print belongs to a specific animal (Miller, 2001). However, accuracy of the basic width and length is still important and thus in order to minimise any error that 4
may occur during the measurement of Jaguar tracks, all future records will involve taking a minimum of 10 sets of track measurements where possible. From this a mean average print size can be calculated and used for analysis. The measurements of individual tracks seems to indicate that there may be different Jaguars in the two areas of high activity (from miles 7 4/8 to 8 and from 9 to 11). Most of the tracks found in the first half of the beach (closer to Tortuguero) were of a Jaguar with hind-foot prints of approximately 80mm x 100mm. This individual was usually found together with another individual with prints of about 80mm x 80mm. The second half of the beach was dominated by a larger Jaguar with hind-foot prints that measured 90mm x 110mm. However, this observation was more evident during Phase 1 (July – September), whereas the prints were more mixed in the two areas towards and after the end of the season (November - February). In addition, weather conditions and thus conditions of the sand make it very difficult to always obtain accurate measurements and good photos of the prints, so it remains a very biased assumption until more valid data supports this theory. Nevertheless, from the data collected so far, it is plausible to assume that there may actually be three different Jaguars walking on the beach in the Tortuguero National Park between mile 4 and 18. The print measurements could indicate a female with a one-year old cub usually in the area between mile 7 to mile 11. These two prints have been observed together many times. The second half of the beach has been dominated by larger Jaguar prints, possibly a male. The tracks from this individual have been recorded most frequently between miles 14 and 17, suggesting that the beach may have two separate Jaguar territories. In the beginning of Phase 1 this data proved consistent as only one size of prints were observed per area. In recent months (January – March) the ranges have been overlapping, and the larger Jaguar prints have been observed as far north as mile 7½ and two prints together (one larger than the other) as far south as mile 16½. Data from fresh turtle carcasses shows that the amount eaten by Jaguars is usually relatively small. They seem to kill the turtle, and then only eat a small amount of the internal organs (including the heart) found immediately below the fat layer. This could be due to the relative low energy expenditure of hunting turtles compared to hunting other prey like peccary (Tayassu spp.), deer or other mammals inside the forest (M. Castro, pers. comm.)
5
Continued data collection will help to improve this monitoring project and will provide a useful tool for the management and conservation of jaguars and turtles in the Tortuguero National Park.
3.
MARINE TURTLE MONITORING PROGRAMME
3.1.
Introduction
Tortuguero National Park was established in 1975 with the main purpose of protecting sea turtles and the nearby areas of humid lowland forest and beach (A. Castro, pers. comm.). The largest Green Turtle (Chelonia mydas) breeding colony in the Atlantic and the western hemisphere is situated in Tortuguero (Troëng, 2000). Over the past 20 years there has been a huge decline in both Leatherback Turtles (Dermochelys coriacea) (Troëng et al., 2004) and Green Turtles (Troëng & Ranking, 2005) due to overexploitation such as illegal harvesting of their meat and eggs, as well as fishing, contamination and habitat alteration. In addition to the general decline in marine turtles, Tortuguero and the surrounding area are continuously developing and thus the demand for protection and conservation of the marine turtles and their habitat is growing. Whilst the protection of wildlife in Tortuguero National Park is contributing to the stability of sea turtle populations, many beaches surrounding the park are supposedly undergoing a high percentage of poaching (J. Daigle, pers. comm.) In response to this, COTERC (Canadian Organization for Tropical Education and Rainforest Conservation) started a five-year long feasibility study in 2004 with the aim of determining nesting populations and poaching rates of Green and Leatherback Turtles on the North Beach. This beach which encompasses the study area is 31/8 miles long and extend from the Tortuguero river mouth (10º36’36,9”N 83º31’52,1”W) at the most southern point until Laguna Cuatro (10º37’56,3”N – 83º32’25,7”W) in the north. Although this beach is not within the Tortuguero National Park boundaries, it is situated within the Barra Colorado Wildlife Refuge, which is also managed by ACTo (Area de Conservacion Tortuguero) under MINAE – the Costa Rican Ministry for Environment and Energy. In July 2005 GVI joined COTERC in collecting data on the unprotected North Beach. As well as collaborating on the data collection and analysis, GVI and COTERC share data with the CCC (Caribbean Conservation Corporation) in order to increase the 6
available turtle data and compare poaching rates of turtles nesting on the National Park beaches. The project will be conducted during the main nesting season of Leatherback Turtles (March to mid-July) (Troeng et al., 2004), and that of Green Turtles (June to November). Data will also be collected during the nesting season for Hawksbill Turtles (Eretmochelys imbricata) and Loggerhead Turtles (Caretta caretta), which extends from June to September, but very few of these species are expected to nest on the North Beach. 3.2.
Aim
According to previous studies (conducted by COTERC) there is a great amount of illegal harvesting of turtle eggs, and to a lesser extent meat, on the North Beach. Thus, the aim of this project is to study the spatial and seasonal distribution of nesting females, the number of nesting emergences, illegal harvesting of turtle meat and eggs, and natural depredation of nests in order to study, monitor and protect the sea turtles coming to nest on the North Beach. 3.3.
Methodology
The methodology used for the marine turtle monitoring programme follows the COTERC and GVI protocol which is adapted from and approved by the CCC. 3.3.1.
Track and Nest Surveys
Each survey consisted of walking the beach between mile 0 and 3 1/8, recording tracks and nesting turtles during 5 hours (9 p.m. to 2 a.m.) for the night team and 2 hours in the morning (starting at 5.30 a.m.) for the day team. The teams identify tracks as full (turtle nested), half moon (turtle came out intending to lay but turned around before even attempting to nest), or a lifted/poached turtle (no tracks going back into the sea). Nests (full tracks) were then identified as either an attempted nest, a natural nest, or a poached nest. Data was also recorded from encountering dead turtles on the beach. The size, sex, state of the turtle, and an estimated time of death were recorded. Any obvious signs of an unnatural death were also recorded such as harpoon marks, machete cuts or blows to the head and/or limbs and photographs are taken. If the turtle had been tagged, the ID number was recorded and checked against CCC tagging data. 7
3.3.2.
Night surveys
The purpose of the night patrols was to collect data from as many turtles as possible. However, considering that the beach is 31/8 miles in length there was a possibility that not all turtles would be observed prior to or during nesting. If a turtle was not observed but the tracks were then standard track data was taken. Once there was confirmation of a nest (body pit and camouflaged egg chamber), it was investigated to identify whether the nest had been illegally harvested (signs of stick marks to find the egg chamber, exposed egg chamber or human foot prints), predated by animals or if remained in its original state. When encountering a turtle on the beach the following data was collected. •
The date and the time that the track was encountered
•
Time when the nesting process ended (if the turtle is encountered before going into the oviposition stage)
•
The initials of each member of the team
•
The mile marker number and GPS of each nest
•
The position of the nesting turtle (turtle facing North, South, East or West) when the turtle is laying eggs
•
The position of the nest on the beach in relation to the vegetation (in vegetation, close to vegetation or on open beach)
•
If the nesting process was observed a count of the number of eggs with yolk and yolkless eggs.
• 3.3.3.
Any other comments or anomalies observed Tagging
Female Leatherback Turtles were tagged on the membrane located between the tail and rear flipper using Monel (metallic) tags. Females were only tagged after having completed the nesting process, while they were covering the nest or returning to the ocean. Evidence of old tags in the flippers, old tag notches (OTN) or old tag holes (OTH) were also recorded as well as evidence of injuries or parasites. 3.3.4.
Biometric Data
For all the turtles encountered the minimum Curved Carapace Length (CCL) and the Curved Carapace Width (CCW) were recorded. Measurements were conducted by 8
two people and reviewed three times. Deformation or pieces missing of the carapace and flippers or any other relevant data was also recorded. 3.3.5.
Human impact data
Due to the recent increase in human activity on the North Beach all artificial light (white or red) observed during the night surveys was recorded. Number of people present and direction of travel was also recorded. 3.4.
Results
Data for Phase 3 was collected during the day between the 1st – 25th March (total: 25 days) covering the beginning of the Leatherback Turtle nesting season. Night surveys started on the night of 10th March, after two researchers from COTERC and GVI completed training provided by the CCC. During the daily track census a total of 812/8 miles (total: 37 hours 22 minutes) was walked, taking an average of 1 hour and 30 minutes to complete the 31/8 miles. Meanwhile, the nightly surveys covered 133 miles (total: 74 hours 16 minutes), taking an average of 5 hours to cover an average of 86/8 miles. 3.4.1.
Track census and nest surveys
All tracks encountered on the North Beach were identified as Leatherbacks. A total of 10 tracks were observed during the survey period divided into five nests and five half moons. The spatial and temporal distribution of activity is shown in figure 3.1 and 3.2.
9
LEATHERBACK TEMPORAL NESTING DISTRIBUTION IN NORTH BEACH 2006 3 2 1
Nest
23 -m ar
21 -m ar
19 -m ar
17 -m ar
15 -m ar
13 -m ar
11 -m ar
9m ar
7m ar
5m ar
3m ar
1m ar
0
Half Mon
LEATHERBACK SPATIAL NESTING DISTRIBUTION IN NORTH BEACH 2006 4 3 2 1 0 0
2/8
4/8
6/8
1
1 2/8 1 4/8 1 6/8 2
Nest
2 2/8 2 4/8 2 6/8 3
3 2/8
Half moon
Figure 3-1 and Figure 3-2 Temporal and spatial nesting distribution of total tracks (nests and half moons) for Leatherbacks (Dermochelys coriacea) on the North Beach during the first month of the nesting season in 2006.
3.4.2.
Monitoring of nests
60% of the nests (n = 3) seemed to be left in their natural state without any signs of poaching, erosion or predation. 20% (n = 1) of the total nests were poached based on various combination of evidence such as human foot prints, stick marks and / or an exposed egg chamber. Finally, it was not posible to determine whether the last 20% (n = 1) was poached or not, although there was evidence of stick marks and a deep hole in the sand which was not exactly where the egg chamber was located. 3.4.3.
Monitoring of female turtles
During three of the 15 days of night surveys, a Leatherback turtle was encountered nesting on the North Beach. The first female (No 1) was encountered during the process of covering her nest and it was not possible to count the eggs laid. The second female (No 2) was encountered during egg chamber excavation and the whole process of counting eggs, tagging and measuring took place. The third female (No 3) was encountered whilst covering her nest and thus it was not possible to go 10
through the normal process of counting eggs. These three turtles came out of the water to nest between the hours of 23:00 and 01:15. 3.4.4.
Tagging
Two of the three turtles (No 1 and No 3) encountered during this phase had already been tagged or had evidence of previous Monel tags (OTH). The second turtle encountered had no evidence of old tags and was thus tagged by the night survey team. See table 3.1 for more details. MONEL TAG's
OTN / OTH
Left
Left
Right
Right
CCL (cm)
CCW (cm)
Turtle No 1
VA1872
-
None
OTH
145
145
-
-
-
Turtle No 2
VA8206
VA8205
None
none
161
161 160,5 116 116,1 116
Turtle No 3
VA2494
VA2495
OTH
none
150
150 149,9 107
107
107
Table 3-1. Number of Monel tags, Details of previous and recent tags and measurements of carapace lenght and width from the turtles encountered during nesting on the North Beach, Tortuguero 2006.
All three turtles presented complete caudal projection and some small bites to the flippers. However, none showed any signs of deformation or any obvious disease. With respect to the position of the nest, all three turtles were found to nest in the open zone, a few metres above the high tide line. 3.4.5.
Biometry of female turtles
The counting of eggs was conducted once (Turtle No 2) and a total of 125 large eggs and 20 small eggs (infertile) were counted. The measurements of the carapace was 152 cm CCL and 111.5 cm, see table 3.1 for more detail. 3.4.6.
Human impact data
During the night surveys a minimum of 2 strong, white lights were observed at various times throughout the patrol. A total of 8 other white lights were observed from various locals or tourists passing by the survey team during a patrol. Only one red light was encountered during the night surveys when meeting a guide with a group of 20 tourists. In various places along the beach a few permanent lights from private houses have been observed, including a very bright external light on the top part of the beach in front of Turtle Beach Lodge. 11
3.5.
Discussion
Since the data collection from Phase 3 only covers the very beginning of the nesting season for Leatherback Turtles, there is only preliminary data from 3 worked turtles, and 25 day and 15 night surveys. In order to obtain better results from nesting female turtles, the aim of the project is to continue collecting data from the entire nesting season of both Leatherbacks and Green Turtles. Final results will be able to give an indication of nesting behaviour, nest success, and the level of poaching as well as comparing this data to future years of research.
3.5.1.
Track census and nest surveys
Five tracks out of the total 10 were recorded as nests and the other five were recorded as half moons, of which 2 presented a body pit and the initiation of egg chamber excavation. The reason why 50% of the turtles made half moons and went back into the sea without nesting could be various (Bjorndal et al., 1999) (due to physical state of the sand, state of the tide, lights, etc.) and perhaps at the end of the nesting season some factors which may have influenced it may be possible to identify this behavior. 3.5.2.
Monitoring of nests
At the moment it is not possible to determine if the nesting follows the Gauss curve (gradual increase in numbers of nesting turtles culminating in a peak at mid-season and then a gradual decrease towards the end of the season), but at the current rate it seems that 1-2 turtles are observed every 2.5 days of work. With respect to nests there has been one nest per five nights of surveys. From the limited data it seems that nesting is concentrated around mile 5/8 and 15/8. As previously mentioned, it is not possible to precisely know if out of the current five nests on the North Beach one or two are poached. Consequently, the poaching rate is somewhere between 20% and 40%, the remainder were left in a natural state.
12
3.5.3.
Tagging and monitoring of female turtles
All three females coming up the beach to nest were tagged, either previously (Turtle No 1 & 3) or by the COTERC/GVI team (turtle No 2). This tagging process will help determine nesting frequency and location of individuals and the interval between nesting events. 3.5.4.
Biometry of female turtles
Based on previous studies, the average number of eggs layed by a nesting Leatherback female is 82 normal sized and 30 infertile with a CCL of 154 cm. The turtle tagged on North Beach varied from these by laying 125 normal eggs, but only 20 infertile eggs and measuring 160.8 cm. These numbers and in particular the carapace length (CCL) seem to indicate that it was not a young adult, but instead an older female which has not been tagged during any of her previous nesting events. 4.
EBCP RESIDENT BIRD PROJECT
4.1.
Introduction
Although much research into the migratory avifauna of the New World has been conducted in Costa Rica, there is still much to be learned about the natural history of residential species. In collaboration with Steven Furino at Waterloo University, Canada, GVI is continuing to accumulate data on the presence of resident and migratory bird species and monitor their seasonal activity patterns in four different sites around the Estación Biológica Caño Palma (EBCP). Steven Furino has designed a programme, ‘WINGS’, in order to make this raw data available to fellow researchers and the general public. In addition, the data may also provide the Costa Rican Ministry of Environment and Energy (MINAE) with a management tool. 4.2.
Aim
The aim of this study is to collect presence data on local bird communities which can then be accessed and used for scientific research by anyone in the world. The data collected may help to identify changes in population trends, migration patterns and habitat usage and prove to become a useful management tool for MINAE and ACTo (Area de Conservación Tortuguero). 13
4.3.
Method
The bird project is conducted using two standard bird monitoring methods; Area Searches and Point Counts which are discussed below. For both survey types the ‘Widdowson Tortuguero Species Checklist’ for birds (Widdowson & Widdowson, 2004) is used to allocate an abundance rating to each bird species recorded. This rating is based on the probability of encountering the species in its preferred habitat in the appropriate season. This system is used to assess how many of the species recorded fall into the following categories: I.
Common; Easily seen most days, often in moderate to high numbers;
II. Fairly Common; Should be seen most days, in small numbers; III. Uncommon; Hard to see, only once or twice a week; IV. Rare; Very hard to see even in appropriate habitat and season; and V. X; Casual, vagrant, or few records; unlikely to see. Also includes species recorded but not on the Widdowson list. In order to achieve and maintain a high standard of data collection, expedition and staff members undergo continuous training on the research methodology and identification of study species. The identification of target species focuses on avian species, examining not only the study species but also those species that may be easily confused with any one of the study species. Appendix 1 contains a list of all the avian study species along with species they could be easily confused with. 4.3.1.
Point Count Method
Point Counts are undertaken at predetermined points within the four study sites. Within each study site there are six points except for Caño Palma where there are five Point Count stations. Dawn Point Counts and Area Searches are conducted between sunrise and 0930, and afternoon Point Counts and Area Searches between 1400 and 1700. Both Point Count and Area Search methods are used in the same four study sites around EBCP. These sites are: I.
CT - Cerro Tortuguero, the highest local point (119m). It possesses a terra firme forest different from the forest near the station. Its height also makes it a favourite spot for soaring raptors; 14
II. NB - North Beach, a 5 km section of sand beach from the mouth of Laguna de Tortuguero to Laguno Cuatro, providing a coastal habitat to study; III. CP - Caño Palma, a 5 km section of narrow canal from EBCP to the entrance to the canal to Laguna Cuatro,; and IV. CA - Cleared Areas, including the grounds of EBCP, the grounds of Cabinas Vista al Mar, and the barrio of San Francisco. When undertaking Point Counts surveyors record all birds seen and heard during a
S
H
S/ H
S
S/ H
H
S
H
S/ H
Notes
S/ H
Habitat (G,L,H,A)
H
Total #
S
>50
Unknown distance
Distance and Cue from point 10-25 25-50
0-10
name)
Species (common
Time observed
Station Code
ten minute period. For each record the following data is taken:
Table 4-1 Data collected during Point Count surveys
During the ten minute period surveyors must remain in the same location, only moving in order to obtain a positive identification. 4.3.2.
Area Search Method
Area Searches are within the same study sites as Point Counts however surveyors are recording data for twenty minute periods whilst moving. Twenty minute surveys are undertaken between predetermined points so as to allow for comparative analysis. Area searches can prove to be more useful for determining species
S/H
Table 4-2 Data collected during Area Searches
15
S
H
S/H
Notes (Male, Female)
H
Habitat (G,L,H,A)
S
Number off site Total # ind.
Species (common name) Species (scientific name)
Number on site Time observed
Station Code
composition within study sites.
4.4.
Results
A total of 110 different species were recorded during the Phase 3 survey period. Table 4-3 presents a breakdown of species abundance and Figure 4-1 shows the same data in graphical format. Abundance Common Fairly common Uncommon Rare
Number of species 69 19 16 3 3 110
X Total
Table 4-3 Species composition of birds, recorded during both Point Counts and Area Searches, based on abundance within the Tortuguero area
120
100
Number of species
80
60
40
20
0 species
common
fairly
uncommon
Rare
X
Figure 4-1 Species composition of birds, recorded during Point Counts, based on abundance within the Tortuguero area
Of the bird species recorded 62% were Common, 17% Fairly Common, 15% Uncommon, 3% Rare and 3% Casual, Vagrant or Few records. The three species recorded during the surveys as rare species within the Tortuguero area, were the Great Black Hawk Buteogallus urubitinga (North Beach), Cinnamon Woodpecker Celeus loricatus (Cerro Tortuguero) and Green Ibis Mesembrinibis cayennensis 16
(Caño Palma). The “X” species were Pomarine Jaeger Stercorarius pomarinus and Yellow-bellied Sapsucker Sphyrapicus varius, both which were recorded on North Beach, and White-lined Tanager Tachyphonus rufus recorded on Cleared Areas. 4.4.1.
Point Count Results
During the Phase 3 survey period a total of 106 different species were recorded during Point Count surveys. Table 4-4 presents a breakdown of species abundance and Figure 4-1 shows the same data in graphical format. Abundance Common Fairly common Uncommon Rare
Number of species 68 19 16 2 1 106
X Total
Table 4-4 Species composition of birds, recorded during Point Counts, based on abundance within the Tortuguero area
80
70
Number of species
60
50
40
30
20
10
0 common
fairly
uncommon
Rare
X
Figure 4-2 Species composition of birds, recorded during Point Counts, based on abundance within the Tortuguero area
Of the bird species recorded 64% were Common, 18% Fairly Common, 15% Uncommon, 2% Rare and 1% Casual, Vagrant or Few records. The two species recorded during Point Counts as rare species within the Tortuguero area, were the Great Black Hawk (North Beach) and Green Ibis (Caño Palma). The one “X” species recorded was the Pomarine Jaeger recorded on North Beach. 17
160
140
number seen/ number of records
120
100
Black Vulture Montezuma Oropendola Bright-rumped Attila Brown Pelican Keel-billed Toucan Semipalmated Plover Stripe-breasted Wren
80
60
40
20
0 CA most numerous
CA most frequent
CP most numerous
CP most frequent
CT most numerous
CT most frequent
NB most numerous
NB most frequent
Figure 4-3 Variation between number of birds and frequency of records during Point Counts
Figure 4-3 illustrates the variation in most numerous and most frequent 3 avian species recorded within each study site. On CA, CP and NB the two most frequent and most numerous birds were the same (Black Vulture Coragyps atratus and Montezuma Oropendola Gymnostinops montezuma on CA; Montezuma Oropendola and Bright-rumped Attila Attila spadiceus on CP; and Brown Pelican Pelecanus occidentalis and Semipalmated Plover Calidris pusilla on NB) however on CT this was not the case. On CT the two most numerous birds were the Brown Pelican and Keel-billed Toucan Ramphastos sulfuratus where as the most frequently recorded species were Keel-billed Toucan and Stripe-breasted Wren Thryothorus thoracicus.
3
Frequent refers to the number of records obtained for the species and numerous refers to
the number of that species recorded e.g. frequent: 10 records, numerous: 25 birds
18
120
100
% of birds
80
CA CP CT NB
60
40
20
0 total number of positive id
total number of family only
total number of Unknown
total number seen
total number heard
Figure 4-4 Variation in identification of species and comparison between seen and heard recordings during Point Counts
The total number of positively identified birds varied between 64% and 76.5%. Positive identification was most successful within the NB study site and least successful along CP. The percentage of birds that could not be identified to either species or family level varied between 3% and 10%. The percentage of ‘unknowns’ was greatest within the CP study site. Of the birds recorded the majority were seen, however the percentage of species seen against species heard varies between study sites. Within the CP and CT study sites the percentage of birds seen were 57% and 54%, respectively, whereas on CA and NB the percentage of birds seen were 86% and 96% respectively. 4.4.2.
Area Search Results Abundance
Number of species
Common
62
Fairly common
17
Uncommon
12
Rare
2
X
2
Total
95
Table 4-5 Species composition of birds, recorded during Area Searches, based on abundance within the Tortuguero area
19
100
90
80
number of species
70
60
50
40
30
20
10
0 species
common
fairly
uncommon
Rare
X
Figure 4-5 Species composition of birds, recorded during Area Searches, based on abundance within the Tortuguero area
Of the bird species recorded 65% were Common, 18% Fairly Common, 13% Uncommon, 2% Rare and 2% Casual, Vagrant or Few records. The two species recorded during Area Searches as rare species within the Tortuguero area, were the Cinnamon Woodpecker (Cerro Tortuguero) and Green Ibis (Caño Palma). The two “X” species were Yellow-bellied Sapsucker (North Beach) and White-lined Tanager (Cleared Areas). 300
number seen or heard/number of records
250
200 Black Vulture Variable Seedeater Great Kiskadee Western Slaty-Antshrike Stripe-breasted Wren Turkey Vulture Semipalmated Plover Brown Pelican
150
100
50
0 CA most numerous
CA most frequent
CP most numerous
CP most frequent
CT most numerous
CT most frequent
NB most numerous
NB most frequent
Figure 4-6 Variation between number of birds and frequency of records during Area Searches.
20
Figure 4-6 illustrates the variation in most numerous and most frequent avian species recorded within each study site. On CP, CT and NB Area Searches the two most frequent and most numerous birds were the same (Western Slaty-Antshrike Thamnophilus atrinucha and Stripe-breasted Wren on CP; Black Vulture and Turkey Vulture Cathartes aura on CP; and Brown Pelican and Semipalmated Plover on NB) however on CA this was not the case. On CA the two most numerous birds were the Black Vulture and Variable Seedeater Sporophila corvina where as the most frequently recorded species were Black Vulture and Great Kiskadee Pitangus sulphuratus.
120
100
% of birds
80
CA CP CT NB
60
40
20
0 total number of positive id
total number of family only
total number of Unknown
total number seen
total number heard
Figure 4-7 Variation in identification of species and comparison between seen and heard recordings during Area Searches.
The total number of positively identified birds varied between 71% and 90%. Positive identification was most successful within the NB study site and least successful along CP. The percentage of birds that could not be identified to either species or family level varied between 2% and 11%. The percentage of ‘unknowns’ was greatest within the CP study site. Of the birds recorded the majority were seen, however the percentage of species seen against species heard varies between study sites. Within the CP and CT study 21
sites the percentage of birds seen were 40% and 74% respectively where as on CA and NB the percentage of birds seen were 90% and 96% respectively. 4.5.
Discussion
The EBCP Resident Bird Project monitoring surveys began in July of 2005 and will continue for several years. As the study is only in its third phase, this early set of data can not be taken as indicative of trends for local bird species. The data collected in this third phase generally supports data collected in the previous two phases. The data confirms that the Cerro Tortuguero is the least species-rich site for avifauna, while the Cleared Areas sites support the highest species richness and remain the best site for relative abundance and diversity. The technique of using both Area Searches and Point Counts to conduct monitoring surveys works as an effective indicator to determine the local bird presence. The two survey techniques seem to generally yield a similar species list. The composition of species found within each study site has been based on all records. Although species were recorded as on or off site, early confusion on the correct definition of these terms has resulted in inconsistent data collection. In order to overcome this issue, to some extent species were analysed based on the number of times they were recorded and the number of individuals 4 recorded. Analysis of both Point Counts and Area Searches indicates that the second most numerous species was generally the best example of significant species for that habitat. Large flocks of pelicans and vultures tended to skew the results. The top two most numerous and common species tended to be the same within sites and survey technique. When species composition was compared between survey technique and study site there was a distinct difference. Although it is difficult at this stage to confirm any reason for this, it appears that small and more audible species were detected during the Area Searches, where as on the Point Counts the larger visual species were recorded.
4
It is recognized that where the term “individual” is used that these do not necessarily refer to different
birds within the population, however for the analysis no differentiation is possible.
22
The overall numbers of rare species is expected to increase as the project becomes more established. Not only will the surveys cover a longer period of time, but the survey techniques are expected to improve along with the training of expedition members and therefore more birds should be identified based on hearing calls/songs as well as by sight. The Tortuguero area offers great opportunities to find rare and accidental species due to its remote location and undisturbed habitats. The location is also an important area for migrating birds and is connected with the Barra Colorado Wildlife Refuge and the large Indio-Maiz National Park in Nicaragua. During Phase 3 a relatively high proportion of X, Rare and Uncommon species were recorded during surveys. This is a promising sign that surveys are being conducted to a high enough standard for these more unusual species to be positively identified. The fact that birds still being identified to only family level or recorded as unidentified, indicates that birds are not being “guessed” where surveyors are not 100% sure of the species these categories are used. The EBCP Resident Bird Project surveys undertaken during Phase 3 have assisted in increasing the overall data set. They have also helped in identifying areas where continued improvement to the methodology is required in order to gain the most useful and accurate data possible. A new key species list will be developed for Phase 4 that will include migratory species in addition to those which are typical of the selected habitats. It will be important that the species list is concise in order to facilitate training and data collection. It must be acknowledged that the aim of the study is to monitor changes in species and not to create a new species list for the Tortuguero area. 5.
NATIONAL PARK TOURIST IMPACT ASSESSMENT
5.1.
Introduction
Tortuguero National Park was created in 1975 in order to protect the large diversity of wildlife that exists within it. The park is managed and protected by the Costa Rican Ministry of Environment and Energy (MINAE). Terrestrial sections of the park consist of primary rainforest and flooded swamplands, which extend from the Caribbean coastline to the foothills of the central Costa Rican mountain range. Aquatic sections of the park include navigable lagoons, canals, and waterways. Terrestrial and aquatic trails are clearly marked and allow tourists the opportunity to experience the impressive species richness of the area; 2200 species of plant, 375 bird species, 125 23
mammal species and 124 species of reptiles and amphibians exist within the park’s boundaries (Bermúdez & Hernández, 2004). The flow of tourists to the national park is regulated by MINAE; however, rising tourist numbers could increase the pressure to the area. Greater accessibility to this region has begun produce a constant influx of groups of tourists using both the aquatic and terrestrial trails. Eco-tourism is encouraged, however it is essential that a certain balance between the park’s human activity and use and the conservation of these fragile ecosystems should be respected (Bermúdez & Hernández, 2004; C. Calvo, pers. comm.). However, there is a potential threat to the biodiversity of the park due to excessive stress from continuous human activity. In the last 15 years, annual totals of visitors to the park have risen from 9,000 to more than 70,000. 5.2.
Aims
Funded by the European Union, in 2005 MINAE developed a Management Plan for Visitors to Tortuguero National Park. However, due to lack of human resources, MINAE requested the assistance of GVI to initiate and implement the Tourism Impact Assessment in order to provide data for an objective and quantitative evaluation of the impact of Tourism in Tortuguero National Park (Bermúdez & Hernández, 2004). The aim of the National Park Tourist Impact Assessment is to document and monitor species abundance and diversity in relation to presence of human activity. The ongoing collection of this data is being documented by GVI in conjunction with MINAE, to accurately assess the degree to which tourists are influencing the park’s biodiversity. The commencement of this data collection was initiated in November 2005 by GVI. This baseline data is essential in order to generate a good understanding of the ecological systems operating in and around the park. As this understanding continues to develop, methodology is adapted to yield the most beneficial results possible. 5.3.
Methods
The National Park Tourist Impact Study consists of three separate research areas, these are: I.
Aquatic Survey; 24
II. Terrestrial Survey; and III. Strawberry Poison Dart Frog Transect. The data obtained from these three research areas assists in the establishment of creating a realistic view into what is happening within the park both on an ecological level and a tourist impact level. 5.3.1.
Aquatic Trails
This part of the study involves surveying two aquatic transects within the National Park; Caño Harold and Caño Chiquero. Transects are conducted between 05:40am and 06:50am on a weekly basis for both Caño Harold and Caño Chiquero. Caño Harold is also surveyed before dusk, commencing at between 13:50 and 15:00. Up to six researchers record avian, reptilian and mammalian species activity using the following data categories: Sector
Time
Species
# Cue
On/Off
Habitat
Notes
Site Figure 5-1 Data categories for aquatic survey.
Each study site has been divided into sections to aid with data recording and analysis. Caño Harold is divided into four sections whilst Caño Chiquero is divided into five sections. AC1 and AC2 (Access 1 and 2) form the first two sectors of either Caño Harold or Chiquero and are thus surveyed during every aquatic survey. The beginning of AC1 is located at the start of Rio Tortugero and continues along the Caño until it reaches the westerly Caño which leads to both Caño Harold and Chiquero. At this point AC2 begins and continues in a westerly direction towards Caño Harold. Where Caño Harold enters AC2, CH1 (Caño Harold 1) begins. CH1 continues up Caño Harold leading into CH2 and CH3 along the way. The survey of Chiquero continues past Caño Harold along AC2. Where AC2 leads into Caño Chiquero, CC1 (Caño Chiquero 1) begins. The transect continues up along the Caño and becomes sector CC2. When a species is observed, a record is made of the sector in which it is located including the time of sighting, the species, number of individuals, cue (whether seen and / or heard), the location (on or off site) and the position within the habitat (Ground Level, Low Level, High Level and Aerial). Points of interests include; behavior, sex and stage are recorded in the notes. 25
The non-avian target species for the aquatic surveys include the Spider Monkey Ateles geoffroyi, Black River Turtle Rhinoclemmys funerea, and Spectacled Caiman Caiman crocodiles. The avian target species are the Anhinga Anhinga anhinga, the Green-backed Heron Butorides virescens, the Cormorant Phalacrocorax brasilianus and all Kingfishers (family Alcedinidae). However, all individuals encountered are identified to species level where possible; where this cannot be achieved family name is recorded. Occasionally it is not possible to obtain either of these categories so the individual is recorded as unknown. Tourist activity is also recorded during each survey, information on number of visitors and the type or name of boats seen (eg. Canoe, Laguna Lodge, no motor, electric motor, 4-stroke motor) is recorded. Individual boats are recorded only once per survey. 5.3.2.
Terrestrial Trail
The Sendero Gavilán is a terrestrial loop trail, 1.920 meters long, located immediately south of the Park Head Office, Cuatro Esquinas. Up to four researchers commence survey at Cuatro Esquinas, and walk counterclockwise around the trail. Data is collected using the same methodology as with the aquatic survey. The only target species for the terrestrial trail are Spider Monkeys Ateles geoffroyi and Strawberry Poison Dart Frogs Dendrobates pumilio, but data is also collected from other mammal and avian species.
The trail is broken into four sectors: I.
G1 – Trail head to 550 meters;
II. G2 – 550m to 1100m (at the path parallel to the beach); III. G3 – 1100m to 1500m (the trail parallel to the beach); and IV. G4 – 1500m (the water tower) to the trail head. 5.3.3.
Strawberry Poison Dart Frog (Dendrobates pumilio) transects
Presence/absence data is collected on Strawberry Poison Dart frogs along two transects cut west (100m from Sendero Gavilán) and south (500m from Sendero
26
Gavilán) of the trail. This frog species, D. pumilio, is believed to have declined possible to the point of local extinction within this area of the national park. 5.4.
Results
The following results highlight the main findings from the research undertaken during phase 3. Data has been analyzed based on the quantity available to produce sound results. Some areas of study will require further research in order to be assessed adequately. 5.4.1.
Aquatic Trails
The two Aquatic Trails were surveyed 24 times during the course of Phase 3, which means that Access 1 and 2 (AC1 and AC2) were surveyed a total of 24 times. However, Caño Harold was surveyed 18 times, 12 of which were dawn surveys. Caño Chiquero was surveyed 6 times, all of which were dawn surveys. The average time taken to complete surveys on Caño Harold was 1.38 hours, whilst Caño Chiquero took an average of 1:15 hours. The average time spent on both aquatic surveys within the national park was 1:33 hours. The average number of records collected on both surveys was 66. On Caño Harold surveys alone the average was 71 and for Caño Chiquero the average was 51. The average number of birds recorded on both surveys was 81. On Caño Harold surveys alone the average was 87 and for Caño Chiquero the average was 65. Figure 5-2 illustrates the percentage difference of the individual Caño compared to the average of both surveys combined.
27
10
% mean difference from combined mean
5
0 Time spent surveying
Number of records
number of birds
-5 Cańo Harold Cańo Chiquero -10
-15
-20
-25
Figure 5-2 Mean percentage difference for combined mean percentage difference for time, number of records and number of birds
The average number of records collected per minute and birds seen per minute are 0.72 and 0.89 on Caño Harold, respectively, and on Caño Chiquero they are 0.68 and 0.87. This data indicates that there is no significant difference in the number of records collected or the number of bird species recorded between the Caño. However when the bird assemblages are examined there is a clear difference in the species present in the various Caño.
28
Most common birds in AC2
Most common birds in AC1 Common name
Latin name
Little Blue Heron Montezuma Oropendola Bare-throated Tiger-Heron
Egretta caerulea Gymnostinops montezuma Tigrisoma mexicanum
Snowy Egret Western SlatyAntshrike Chestnut-backed Antbird
Egretta thula Thamnophilus atrinucha Myrmeciza exsul
Number seen
Common name Montezuma Oropendola
117 45
Little Blue Heron Bare-throated Tiger-Heron Short-billed Pigeon
33 26 16
Sungrebe Stripe-breasted Wren
15
Most common birds in CC Common name
Latin name
Little Blue Heron Montezuma Oropendola Western SlatyAntshrike
Egretta caerulea Gymnostinops montezuma Thamnophilus atrinucha
Sungrebe Stripe-breasted Wren Chestnut-backed Antbird
Heliornis fulica Thryothorus thoracicus Myrmeciza exsul
Latin name Gymnostinop s montezuma Egretta caerulea Tigrisoma mexicanum Patagioenas nigrirostris Heliornis fulica Thryothorus thoracicus
Number seen 35 26 8 7 7 6
Most common birds in CH Number seen
Common name Little Blue Heron Green-backed Heron
31 16 9
Snowy Egret Bare-throated Tiger-Heron Short-billed Pigeon Western SlatyAntshrike
7 6 6
Latin name Egretta caerulea Butorides virescens Egretta thula Tigrisoma mexicanum Patagioenas nigrirostris Thamnophilus atrinucha
Number seen 138 88 42 38 38 36
Table 5-1 Comparison of the six most common bird species found within the different study areas
The Little Blue Heron Egretta caerulea was the most common bird species recorded on three of the four Caño sectors. The variation between species composition increases when the 2nd to 6th most common species are examined. In addition to the avian records, data was also collected on the presences of other families, the following were all recorded during aquatic surveys: Mantled Howler Monkey Allouata palliate, Spider Monkey Ateles geoffroyi, White-faced Capuchin Cebus capucinus, Monkey Cebidae sp., Black River Turtle Rhinoclemmys funerea, Spectacled Caiman Caiman crocodilus, Neotropical River Otter Lutra longicaudis, Dolphin Delphinidae, Bat Chiroptera ord., Basilisk Basiliscus sp., Iguana Iguana iguana, Lizard Norops sp.. Figure 5-3 shows the number of individuals of the top six species recorded on the aquatic survey.
29
120
100
number seen/heard
80
60
40
20
0 Mantled Howler Monkey
White-faced Capuchin
Spider Monkey
Neotropical River Otter
Black River Turtle
Spectacled Caiman
Figure 5-3 Quantity of the top six non-avian species recorded during aquatic surveys
CH
CC Mantled Howler Monkey White-faced Capuchin Spider Monkey Neotropical River Otter Black River Turtle Spectacled Caimen AC2
AC1
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
% of individual species
Figure 5-4 Distribution of non-avian species within Aquatic Study site
The data collected on non-avian species illustrates that Mantled Howler Monkeys are the most common non-avian species within all Caño sectors except Caño Harold where the most common species was Spider Monkey.
30
5.4.2.
Terrestrial Trail
The terrestrial trail Sendero Gavilán was surveyed eight times during Phase 3 in the morning hours, starting before or at 06:30, for an average of 1:49 hours per survey. 52% of recorded species were noted in sector G1, 19% in both G2 and G3, and the remaining 10% of recorded species were seen in sector G4. 73% of all recorded animals were birds, 23% mammals, 3% reptile and 1% amphibians throughout the Gavilán.
140
120
number seen or heard
100
Amphibian
80
Bird Mammal Reptile
60
40
20
0 G1
G2
G3
G4
Sector
Figure 5-5 Number of individuals recorded per trail sector
5.4.3.
Strawberry Poison Dart Frog (Dendrobates pumilio) Transects
The two transects were sampled eight times during Phase 3. No Dendrobates pumilio were recorded, however, two Tree Climbing Toads Bufo coniferus, one Veined Tree Frog Hyla phlebodes and a Gulf Coast Toad were all positively identified during the surveys. 5.5.
Discussion
Although methodologies have been identified, the data collected is at the preliminary stage, where further modifications and increased data samples are necessary. 31
All target species sightings (birds, reptiles and mammals) were recorded on the surveys and data on visitor numbers and transport mode was also recorded. This is very important and quantifiable data which is necessary to properly assess the impact tourist presence is having on wildlife within the Park. However, current sample sizes are too small at the moment and more data should be collected before any indepth analysis can take place. From the data collected during this phase of the study some preliminary conclusions can be presented. 5.5.1.
Aquatic Trails
The data colleted from the Aquatic Trails indicates the unit effort is constant throughout the survey period. This factor eliminates any effort biases that may occur due to different surveyors undertaking the research at different times. This unit effort should be monitored during future phases to ensure it remains constant in relation to the survey technique. Analysis of the data indicates possible patterns in relation to bird assemblages within the different Caños of the study site. Although the volume of data collected between Caño Harold and Caño Chiquero were very similar, there were distinct differences in the species recorded. Further data collection will help to confirm this pattern, whilst analysis of other variable will be helpful to find why this difference is occurring. The data collected on the Aquatic Trail illustrated that of the aquatic species recorded, the herons, egrets and Sun Grebes were the most common. The other species recorded as the most common species were all very auditable species and not necessarily good indicators of the Caño habitats. The non-avian species recorded varied distinctively between Caños. For example AC1 had the largest number of Mantled Howler Monkeys recorded whereas Caño Harold had the highest number of Spider Monkeys. Consistently large numbers of Mantled Howler Monkeys were recorded. A significant proportion of these records were obtained on audio bases and due to the nature of the species they are considerably more audible then any other non-avian species within the study. The number of other non-avian species recorded does not necessarily refer to quantity within the area but may be an indication of ease of viewing. Adjustments to the methodology based on data collected to date will enable a more accurate picture of both species abundance and area usage within the National Park. 32
5.5.2.
Terrestrial Trails
The Terrestrial Trail within the National Park have provided some interesting results during this phase. The difference in species composition and abundance is the most obvious area to examine. There are three distinct areas based on the aforementioned factors; G1, G2 & G4 and G3. G1 was the most abundant and species-rich area, being the only area where amphibians, reptiles, mammals and birds were all recorded. On G2 and G4 birds, mammals and reptiles were all recorded and on G3 only birds and mammals were recorded. These variations could be due to a variety of variables that if deemed necessary could be investigated at a later date. An interesting factor that can be extracted from this data is the presence of amphibians only in G1. It could be speculated that it is because amphibians are more likely to be present in the area closer to the river than to the beach, and that a transect closer to the river but further away from the trail would be worth considering for the Strawberry Poison Dart frogs transects. 5.5.3.
Strawberry Poison Dart Frog Transects
The absence of Strawberry Poison Dart frogs is not surprising as there is a general consensus in Tortuguero and with the National Park staff at Cuatro Esquinas that this species has not been observed in the last 4–10 years. The surveys have been undertaken over three phases to date with no positive record of Strawberry Poison Dart frogs. The preliminary conclusions at this point of the study would indicate that no Strawberry Poison Dart frogs have been recorded within the areas currently being surveyed.
6.
TOURIST IMPACT SURVEY CAÑO PALMA
6.1.
Introduction
Caño Palma is located within the Barra Colorado Wildlife Refuge, immediately north of the river Petenencia, about 7 km northwest of Tortuguero village and National 33
Park. Although not part of the National Park, this caño is included in the Management Plan for Visitors as it provides a suitable alternative for wildlife viewing to the National Park and thus helps to reduce the demand on the other caños (Bermúdez & Hernández, 2004). Proposed restrictions on the number of boats allowed into the National Park are due to be put in place at the end of April 2006. This is likely to increase the number of tourist boats using Caño Palma, and baseline data before this occurs is thus necessary. 6.2.
Aims
GVI has initiated the Tourist Impact Survey Caño Palma in order to estimate the intensity of the tourist activity and assess any change to species composition which could be directly related to the change in volume of usage on the Caño. 6.3. 6.3.1.
Methods Aquatic Trails
The aquatic surveys along Caño Palma are commenced between 05:30am and 06:30am or before dusk in the afternoon. Up to six researchers record avian, reptilian and mammalian species activity using the following data categories: Sector
Time
Species
# Cue
On/Off
Habitat
Notes
Site Figure 6-1 Data categories for aquatic survey
The study site has been divided into 5 sections (CP1 – 5) to aid with data recording and analysis. When a species is observed, a record is made of the sector in which the researchers are located, the time of sighting, the species, number of individuals, cue (whether seen/heard or seen and heard), the location (on or off site) and the position within the habitat (Ground Level, Low Level, High Level and Aerial). Any points of interests including; behavior, sex and stage are recorded in the notes. All individuals are identified to species level where possible; where this cannot be achieved family name is recorded. Occasionally it is not possible to obtain either of these categories so the individual is recorded as unknown.
34
Tourist activity is also recorded during each survey, information on number of visitors and the type or name of boats seen (eg. Canoe, Laguna Lodge, no motor, electric motor, 4-stroke motor) is recorded. Individual boats are recorded only once per survey. 6.3.2.
Boat Dock Survey
The Boat Dock Survey is commenced at 06:00 and continues for 12 consecutive hours. During the survey data is collected on all boats passing the boat dock. For each craft observed the following data is collected: I.
Time of observation
II. Number of passengers on each boat III. Boat name IV. Boat direction V. Time spent on canal VI. Engine type Any additional information that is considered to potentially be of use at a later date is recorded in notes. 6.4. 6.4.1.
Results Aquatic Trails
A total of 20 hours and 50 minutes was spent undertaking the aquatic surveys on Caño Palma. This consisted of 9 surveys between the 30 January and 20 March 2006. Of these 9 surveys one 5 has been excluded in the analysis of mean average data presented in figure 6- 2 because the data was collected in adverse weather conditions.
5
Data excluded from this section was gathered on 14th February.
35
3
2.5
number seen or heard
2
CP NP
1.5
1
0.5
0 average number of records per minute
average number of birds per minute
Figure 6-2 Comparison of mean average data from National Park and Caño Palma
The data in figure 6-2 shows that the mean average rate of records per minute is considerably higher in Caño Palma than within the National Park. The species that are most commonly recorded are also very different from any of the National Park Caños. Figure 6-3 illustrates the top 6 avian species recorded.
60
50
number seen or heard
40
30
20
10
0 Stripe-Breasted Wren
Montezuma Oropendola
Bright-rumped Attila
Western Slaty-Antshrike
Short-Billed Pigeon
Chestnut-backed Antbird
Figure 6-3 Top 6 avian species recorded on Caño Palma
Non-avian species were relatively infrequent during the surveys with Mantled Howler Monkeys being the most common species recorded. As with the National Park, a significant proportion of these were audio records (9 out of 25). 36
6.4.2.
Boat Dock Survey
A Tourist Impact Survey was carried out from the boat dock of Estación Biológica Cano Palma (EBCP), for twelve hours (during the hours of 06:00 to 18:00) on five separate days. Based on the limited data collated to date, the mean daily average of boats passing the station was 38.2. Laguna Lodge, Turtle Beach Lodge, Mawamba Lodge and Pachira Lodge were the most frequently observed tourist boats on Caño Palma. A significant proportion of the boats using Caño Palma can be attributed to these four lodges. 6.5.
Discussion
The Tourist Impact Survey Caño Palma has been in operation for one phase. In this time only a limited data set has been gathered. From this information only limited results can be extracted. As the data set expands with further data collection, a clear picture of localized tourist impact will become apparent. 6.5.1.
Aquatic Trails
The data gathered during the Aquatic Survey indicates that Caño Palma has a higher level of avian species abundance than the surveyed areas within the National Park. Based on this it would seem logical that it would be more appealing to tourists, however the top species composition consists almost entirely of species identified through calls only. This factor instantly reduces the value to Caño Palma to tourist in comparison to the National Park. The low number of heron and egret species compared to the National Park could be attributed to a number of factors, including level of disturbance, habitat type and water quality. Further research into these factors will help to identify possible reasons for the difference in species composition.
37
6.5.2.
Boat Dock Survey
The initial finds from the first phase of research in to this study have provided the study with baseline data. At present only 5 data sets have been obtained, therefore it is difficult to draw any sound conclusions from the data at present. As the data set increases so will its value and therefore long term analysis will be possible. The survey work undertaken in Phase 3 will be used to modify the methodology in order to gather the most relevant data required.
38
7.
COMMUNITY WORK
7.1.
Introduction
People of different nations increasingly utilize English as a common language in order to communicate with one another. Costa Rica, and in particular Tortuguero, hosts a growing number of international visitors each year. The people living in this area rely heavily on the international community and the tourism market. Acquisition of English language skills is one tool for accessing this market. GVI uses the teaching/learning theories and methodologies used by the TEFL Program (Teaching English as a Foreign Language). 7.2.
Aims
The following are the main aims of the teaching programme: I. Local community training/capacity building. II. Increase sustainable revenue to the local communities. III. Generate local community commitment to environment conservation and sustainable development. IV. Language and Cultural Exchange. V. Provide authentic opportunities for local students to practice listening and speaking English with native speakers. VI. Provide an introductory course in the methodology of TEFL for Expedition Members. 7.3.
Method
GVI, in collaboration with the local Peace Corp, conducted English lessons twice a week in the Village of Tortuguero for one hour each, for four weeks, from January 30th through February 25. The following 4 weeks, GVI taught English classes in the adjacent community of San Francisco. Throughout the 8 weeks, simultaneous Language / Cultural exchanges, or Inter-cambios, were scheduled in both San Francisco and with the Tortuguero National Park Rangers. The English lessons were created, written and adapted to fit the proficiency, the desired content, and the comfort level of the students and the teachers. Preparing and teaching in teams of two, Expedition Members had the opportunity to share ideas and work together. Each pair of teachers had a group of 3-5 students, who had comparable language skills. Planning took place in the afternoons and teaching in the evenings. The lessons focused mostly on oral skills rather than written work.
39
7.4.
Results
Along with two Peace Corp Volunteers, 8 GVI teachers taught 20 students in Tortuguero for a total of 8 contact hours. The average teacher: student ratio was 1:2. 12 GVI teachers conducted 8 hours of Language classes for 30 adult students and 18 children from the community of San Francisco. Average teacher: adult student ratio 1:2, teacher: child student ratio 1:7. GVI has continued the commitment to offer the adult English language programme in San Francisco during Phase 3, and GVI has also maintained support for the children’s programme supporting the national curriculum and local primary school. During Phase 3 GVI continued the Inter-cambio programme (a language and cultural exchange programme) between 12 Expedition Members and 4 Costa Rican citizens up to twice a week. The information exchange took place for a total of 55 hours. All Expedition Members received fundamental training in teaching English as a foreign language utilizing the TEFL system. 7.5.
Discussion
Phase 3 ended with the successful completion of 70 teaching contact hours among a total of 16 GVI teachers and 72 students. The atmosphere was relaxed and fun, but. the participants worked very hard and are extremely grateful to GVI for receiving the lessons. The lessons were given and received with great enthusiasm. When polled, our students overwhelmingly responded that their reason for learning English is to help them obtain jobs in the tourism industry. Students are keen to learn English and thus increase personal capacity building in order to improve chances of getting work or a better job within the thriving tourism of Tortuguero. The community of San Francisco is also generally interested in GVI’s presence and work in the area, and the meetings have built friendships and mutual respect.
40
8.
SUMMARY CONCLUSION
Phase 3 of the Costa Rican Rainforest and Wildlife Conservation Expedition has been successful in continuing the collection of scientific data from the 4 established biological projects. Data for the monitoring of Jaguar predation on marine turtles has continued for MINAE in this third phase. Although this period covers the non-nesting and low density nesting periods, it seems that Jaguar presence on the beach of Tortuguero National Park is still strong. In partnership with COTERC, GVI has continued the monitoring programme of marine turtles on the North Beach in order to gain more knowledge from tagged turtles and compare poaching rates of turtles nesting on protected National Park beaches. The programme involves track census and monitoring and tagging of nesting females was begun this phase. The ultimate aim is to support future protection and conservation of marine turtles nesting on the North Beach of Tortuguero. GVI has continued to collect data for the Resident Bird Project in association with Steven Furino of Waterloo University, Canada. The methodology for collecting data follows the protocols of Area Search and Point Counts techniques. The target species list has been revised and the bird identification training has been expanded. This focus on target indicator species has qualitatively improved the data collection. The Tourist Impact Assessment project in Tortuguero National Park has been successful in collecting preliminary data from the aquatic trails Caño Harold and Caño Chiquero, as well as the terrestrial trail Sendero Gavilán. Further modifications and increased data samples are necessary along with continued correspondence with MINAE.Additionally, during phase 3, GVI collected data on target species and tourist boat activity in Caño Palma. Community work has played an important part of the expedition as it is in high demand from the local communities and very enjoyable for Expedition Members. A 4week course in English language lessons for adults was conducted at Laguna Lodge in collaboration with the Peace Corp during the first half of the phase. In the second half of the phase, we returned once more to San Francisco, where English lessons were given to adults and children with much joy and success. An “Introduction to 41
TEFL” course was introduced in Phase 3 with the aim of better preparing the Expedition Members for teaching English successfully. Inter-cambio - cultural and language exchange opportunities – have again been highly successful. In addition to the two staff at Cabinas Vista al Mar, GVI has commenced Inter-cambio sessions with the staff at Tortuguero National Park. These sessions have been very positive and popular. Finally, the third expedition phase has been very successful. The 4 biological projects are becoming well established and the community work is taking shape and becoming an integral part of the expedition. Our partnership with MINAE and COTERC is becoming stronger through the relevant projects and in this way GVI Costa Rica continues to provide valuable data and support to conservation goals of the Tortuguero Conservation Area.
42
9.
Bibliography
Autar, L. 1994. Sea turtles attacked and killed by Jaguars in Suriname. Marine Turtle Newsletter 67:11-12. Bermúdez, F. A. & Hernández, C. A. 2004. Plan de Manejo para los Visitantes al Parque Nacional Tortuguero. Ministerio del Ambiente y Energía Sistema Nacional de Areas de Conservación Area de Conservación Tortuguero. 113 pages. Bjorndal, K.A., Wetherall, J. A., Bolten, A. B., & Mortimer, J. A. 1999. Twenty-Six Years of Green Turtle Nesting at Tortuguero, Costa Rica: An Encouraging Trend. Conservation Biology 13 (1): 126-134. Chacón, D., Valerín, N., Gamboa, H. & Marín, G. 1999. Manual de mejores prácticas de conservación de las tortugas marinas en Centroamérica. P.19. Miller, C. M. 2001. Measurement of Jaguar Tracks: a promising means to identify individuals, Track Collection Protocols, Belize. Troëng, S. 2000. Predation of green (Chelonia mydas) and Leatherback (Dermochelys coriacea) turtles by Jaguars (Pantera onca) at Tortuguero Nacional Park, Costa Rica. Chel. Cons. Biol. 3 (4):751-753. Troëng, S., Chacón, D. & Dick, B. 2004. Possible decline in Leatherback Turtle Dermochelys coriacea nesting along the coast of Caribbean Central America. Oryx, 38 (4), 395 - 403. Troëng, S. & Rankin, E. 2005. Long-term conservation efforts contribute to positive Green Turtle Chelonia mydas nesting trend at Tortuguero, Costa Rica. Biological Conservation, 121, 111 - 116 Widdowson, W. P. & Widdowson, M. J. 2004. Checklist to the Birds of Tortuguero, Costa Rica. Caribbean Conservation Corporation, San Jose, Costa Rica.
43
APPENDIX Appendix 1. GVI Costa Rica Key Avian Species List
Beach and near-shore waters Fresh water: canals, lagoons & marshes
cont.
1
Rufescent Tiger-Heron
46
Collared Plover
2
Bare-Throated Tiger Heron
47
Wilson´s Plover
3
Yellow-crowned Night-Heron
48
Killdeer
4
Green Heron
49
Black-bellied Plover
5
Little Blue Heron
6
Great Blue Heron
7
Boat-billed Heron
50
White-crowned Parrot
8
Tricolored Heron
51
Red-lored Parrot
9
Agami Heron
52
Mealy Parrot
10
Anhinga
53
Brown-hooded Parrot
11
Great Egret
54
Orange-chinned Parakeet
12
Cattle Egret
55
Olive-throated Parakeet
13
Snowy Egret
56
Crimson-fronted Parakeet
14
Osprey
15
Ringed Kingfisher
16
American Pygmy Kingfisher
57
Squirrel Cuckoo
17
Belted Kingfisher
58
Mangrove Cuckoo
18
Green Kingfisher
59
Long-billed Hermit
19
Amazon Kingfisher
60
Band-tailed Barbthroat
20
Green-and-rufous Kingfisher
61
Great Kiskadee
62
Boat-billed Flycatcher
Forest, including swamp & terra firme
63
White-ringed Flycatcher
21
Broad-winged Hawk
64
Gray-capped Flycatcher
22
Double-toothed Kite
65
Social Flycatcher
23
Collared Aracari
66
Tropical Kingbird
24
Keel-billed Toucan
67
Eastern Kingbird
25
Chestnut-mandibled Toucan
68
Clay-coloured Robin
26
Rufous-tailed Hummingbird
69
Rufous Mourner
27
Green-breasted Mango
70
Dusky Antbird
28
Blue-throated Goldentail
71
Passerini´s Tanager
29
Cinnamon Hummingbird
72
Blue-grey Tanager
30
Pale-billed Woodpecker
73
Palm Tanager
Clearings
Clearings continued
44
31
Lineated Woodpecker
74
Olive Tanager
32
Northern Barred-Woodcreeper
75
Scarlet-rumped Cacique
33
Streak-headed Woodcreeper
76
Olive-backed Euphonia
34
Plain-brown Woodcreeper
77
Yellow-crowned Euphonia
35
Wedge-billed Woodcreeper
78
Blue-black Grassquit
36
Black-striped Woodcreeper
79
Variable Seedeater
37
Bright-rumped Attila
80
Thick-billed seed-finch
38
White-collared Manakin
81
Montezuma Oropendola
39
Red-capped Manakin
40
White-ruffed Manakin
Aerial
Beach and near-shore waters
82
Black Vulture
83
Turkey Vulture
41
Neotropic Cormorant
42
Brown Pelican
Note: Species in the above table that
43
Common Black-Hawk
are presented in normal text are Key
44
Great Black-Hawk
Species. Species in italics are not Key
45
Semipalmated Plover
Species but may be confused with one or more of the Key Species.
Audio 1
Pale-billed Woodpecker
16
Chestnut-mandibled Toucan
2
Lineated Woodpecker
17
White-collared Manakin
3
Black-cheeked Woodpecker
18
Squirrel Cuckoo
4
White-crowned Parrot
19
Clay-colored Robin
5
Red-lored Parrot
20
Band-backed Wren
6
Mealy Parrot
21
Black-throated Wren
7
Bright-rumped Attila
22
Bay Wren
8
Great Kiskadee
23
Stripe-breasted Wren
9
Social Flycatcher
24
Plain Wren
10
Lesser Greenlet
25
House Wren
11
Blue-black Grassquit
26
White-breasted Wood-Wren
12
Variable Seedeater
27
Nightingale Wren
13
Montezuma Oropendola
28
Song Wren
14
Collared Aracari
29
Slaty-tailed Trogon
15
Keel-billed Toucan
30
Western Slaty-Antshrike
45
Britt M. Larsen, Nicole Evans, Lydia Chaparro and James P. Lewis
1.
EXECUTIVE SUMMARY
The third 10-week phase of the Costa Rican Global Vision International (GVI) Expedition has now been completed. The expedition has continued to gather important environmental scientific data whilst working with local, national and international partners. The expedition has also maintained working relationships with local communities through both English classes and Inter-cambio. The following projects have been run during phase 3: I.
Jaguar predation on sea turtles. In collaboration with the Costa Rica Ministry of Environment and Energy (MINAE);
II. Marine Turtle Monitoring Programme (collaboration with the Canadian Organization for Tropical Education and Rainforest Conservation (COTERC), MINAE and the Caribbean Conservation Corporation (CCC)); III. EBCP Resident Bird Project (collaboration with Steven Furino, Waterloo University, Canada); IV. Tourist impact assessment within the Tortuguero National Park; V. English language lessons (collaboration with the San Francisco community); and VI. Inter-cambio with staff from Cabinas Vista al Mar and the Tortuguero National Park staff at Cuatro Esquinas. GVI has initiated an additional preliminary study during phase 3: VII. Tourist impact assessment on Caño Palma canal in addition to and in comparison with the tourist impact assessment conducted in Tortuguero National Park.
i
1.1.
Introduction
The Coastal Rainforest Conservation Expedition at the Biological Station Caño Palma in Tortuguero, Costa Rica has now completed its third phase (3 x 10 weeks). The expedition to date has assisted in collecting a substantial amount of scientific data. Although this data is already helping to identify potential future research areas and providing important data to the international scientific community it is still at the preliminary stage. Methodologies continue to be improved and focused as experience is gained and improvement to data quality is continuous. A full Annual Report in December 2006 will collate and summarize all data and enable more descriptive and accurate analysis. The main aim of the GVI projects established with MINAE is to collect raw data, which will then be handed over to MINAE for collation, analysis and comparison with other relevant data.
Acknowledgements This report is successful due to the hard work of all Expedition Members who took part in this third phase of the Costa Rican Rainforest and Wildlife Expedition: Andrew Metcalfe Joanna Miller Amie Smith Ben Stubbens Nadia Gergova Jennifer Smith Tracy Keyte
Alyssa Mummert Melissa Martin Derek Harder Sally-Ann Haw Clayton Bostock Helen Smith Kelsey Doods
Julie Jackson Karen Donnor Jayne Elliott Gabriela Mora Camac Holly Guest Alan Collins
We also thank our partners COTERC, MINAE, ACTo, Steven Furino, and San Francisco community for all their help and support.
ii
Contents 1.
EXECUTIVE SUMMARY .......................................................................................i 1.1.
2.
3.
Introduction................................................................................................... ii
JAGUAR PREDATION ON MARINE TURTLES...................................................1 2.1.
Introduction...................................................................................................1
2.2.
Aim ...............................................................................................................1
2.3.
Methodology .................................................................................................1
2.4.
Results .........................................................................................................2
2.5.
Discussion ....................................................................................................3
MARINE TURTLE MONITORING PROGRAMME................................................6 3.1.
Introduction...................................................................................................6
3.2.
Aim ...............................................................................................................7
3.3.
Methodology .................................................................................................7
3.3.1.
Track and Nest Surveys .......................................................................7
3.3.2.
Night surveys........................................................................................8
3.3.3.
Tagging.................................................................................................8
3.3.4.
Biometric Data ......................................................................................8
3.3.5.
Human impact data ..............................................................................9
3.4.
Results .........................................................................................................9
3.4.1.
Track census and nest surveys ............................................................9
3.4.2.
Monitoring of nests .............................................................................10
iii
3.4.3.
Monitoring of female turtles ................................................................10
3.4.4.
Tagging...............................................................................................11
3.4.5.
Biometry of female turtles...................................................................11
3.4.6.
Human impact data ............................................................................11
3.5.
4.
3.5.1.
Track census and nest surveys ..........................................................12
3.5.2.
Monitoring of nests .............................................................................12
3.5.3.
Tagging and monitoring of female turtles ...........................................13
3.5.4.
Biometry of female turtles...................................................................13
EBCP RESIDENT BIRD PROJECT....................................................................13 4.1.
Introduction.................................................................................................13
4.2.
Aim .............................................................................................................13
4.3.
Method .......................................................................................................14
4.3.1.
Point Count Method............................................................................14
4.3.2.
Area Search Method...........................................................................15
4.4.
Results .......................................................................................................16
4.4.1.
Point Count Results............................................................................17
4.4.2.
Area Search Results...........................................................................19
4.5. 5.
Discussion ..................................................................................................12
Discussion ..................................................................................................22
NATIONAL PARK TOURIST IMPACT ASSESSMENT ......................................23 5.1.
Introduction.................................................................................................23
iv
5.2.
Aims ...........................................................................................................24
5.3.
Methods......................................................................................................24
5.3.1.
Aquatic Trails......................................................................................25
5.3.2.
Terrestrial Trail ...................................................................................26
5.3.3.
Strawberry Poison Dart Frog (Dendrobates pumilio) transects ..........26
5.4.
5.4.1.
Aquatic Trails......................................................................................27
5.4.2.
Terrestrial Trail ...................................................................................31
5.4.3.
Strawberry Poison Dart Frog (Dendrobates pumilio) Transects .........31
5.5.
6.
Results .......................................................................................................27
Discussion ..................................................................................................31
5.5.1.
Aquatic Trails......................................................................................32
5.5.2.
Terrestrial Trails..................................................................................33
5.5.3.
Strawberry Poison Dart Frog Transects .............................................33
TOURIST IMPACT SURVEY CAÑO PALMA .....................................................33 6.1.
Introduction.................................................................................................33
6.2.
Aims ...........................................................................................................34
6.3.
Methods......................................................................................................34
6.3.1.
Aquatic Trails......................................................................................34
6.3.2.
Boat Dock Survey...............................................................................35
6.4.
Results .......................................................................................................35
6.4.1.
Aquatic Trails......................................................................................35
v
6.4.2. 6.5.
7.
Boat Dock Survey...............................................................................37
Discussion ..................................................................................................37
6.5.1.
Aquatic Trails......................................................................................37
6.5.2.
Boat Dock Survey...............................................................................38
COMMUNITY WORK..........................................................................................39 7.1.
Introduction.................................................................................................39
7.2.
Aims ...........................................................................................................39
7.3.
Method .......................................................................................................39
7.4.
Results .......................................................................................................40
7.5.
Discussion ..................................................................................................40
8.
SUMMARY CONCLUSION.................................................................................41
9.
Bibliography ........................................................................................................43
vi
Tables Table 3-1. Number of Monel tags, Details of previous and recent tags and measurements of carapace lenght and width from the turtles encountered during nesting on the North Beach, Tortuguero 2006. ..........................................................11 Table 4-1 Data collected during Point Count surveys ................................................15 Table 4-2 Data collected during Area Searches ........................................................15 Table 4-3 Species composition of birds, recorded during both Point Counts and Area Searches, based on abundance within the Tortuguero area .....................................16 Table 4-4 Species composition of birds, recorded during Point Counts, based on abundance within the Tortuguero area ......................................................................17 Table 4-5 Species composition of birds, recorded during Area Searches, based on abundance within the Tortuguero area ......................................................................19 Table 5-1 Comparison of the six most common bird species found within the different study areas.................................................................................................................29 Figures Figure 2-1 Beach distribution of Jaguar and turtle track along the 14.5 miles in Tortuguero National Park. Period: 3 February – 22 March 2006……………………….3 Figure 2-2 Date distribution of tracks (Jaguar and Turtles) and turtle carcasses in Tortuguero
National
Park.
Period:
3
February
–
22
March
2006.…………………………………………………………………………………………..4 Figure 3-1 and Figure 3-2 Temporal and spatial nesting distribution of total tracks (nests and half moons) for Leatherbacks (Dermochelys coriacea) on the North Beach during the first month of the nesting season in 2006. ................................................10 Figure 4-1 Species composition of birds, recorded during Point Counts, based on abundance within the Tortuguero area ......................................................................16 Figure 4-2 Species composition of birds, recorded during Point Counts, based on abundance within the Tortuguero area ......................................................................17 vii
Figure 4-3 Variation between number of birds and frequency of records during Point Counts........................................................................................................................18 Figure 4-4 Variation in identification of species and comparison between seen and heard recordings during Point Counts........................................................................19 Figure 4-5 Species composition of birds, recorded during Area Searches, based on abundance within the Tortuguero area ......................................................................20 Figure 4-6 Variation between number of birds and frequency of records during Area Searches. ...................................................................................................................20 Figure 4-7 Variation in identification of species and comparison between seen and heard recordings during Area Searches. ...................................................................21 Figure 5-1 Data categories for aquatic survey. ..........................................................25 Figure 5-2 Mean percentage difference for combined mean percentage difference for time, number of records and number of birds ............................................................28 Figure 5-3 Quantity of the top six non-avian species recorded during aquatic surveys ...................................................................................................................................30 Figure 5-4 Distribution of non-avian species within Aquatic Study site......................30 Figure 5-5 Number of individuals recorded per trail sector ........................................31 Figure 6-1 Data categories for aquatic survey ...........................................................34 Figure 6-2 Comparison of mean average data from National Park and Caño Palma 36 Figure 6-3 Top 6 avian species recorded on Caño Palma.........................................36
Appendix Appendix 1. GVI Costa Rica Key Avian Species List…………………………………..44
viii
2.
JAGUAR PREDATION ON MARINE TURTLES
2.1.
Introduction
Marine turtle predation by Jaguars (Panthera onca) seems to have increased within the past 10 years in Tortuguero National Park (Troëng, 2000; Magally Castro, pers. comm.). In 1998 a minimum of 25 Green Turtles (Chelonia mydas) were killed by Jaguars in Tortuguero National Park and several sightings occurred in the late 1990’s (Troëng, 2000). Although there is not much evidence of this atypical foraging behaviour, documentation exists from Suriname, where 82 Green Turtles were killed in the period 1963-1973 (Autar, 1994) and French Guiana (Troëng, 2000). Data has also been collated from the Pacific Coast of Costa Rica, where Jaguars prey upon Olive Ridleys (Lepidochelys olivacea), Black (Chelonia agassizii) and Hawksbill Turtles (Eretmochelys imbricata) (Troëng, 2000). Due to lack of human resources the Costa Rican Ministry of Environment and Energy (MINAE) invited GVI to continue data collection on Jaguar presence and predation of marine turtles in Tortuguero National Park. Data collection has now been conducted by GVI since 11 July 2005, and together with the existing sets of data collected by MINAE, it will aid in their future analysis in order to use as a tool for further management of Jaguars, turtles and their habitat in Tortuguero National Park. 2.2.
Aim
The Jaguar project aims to document the presence of Jaguars (Panthera onca) on the beach of Tortuguero National Park and their predation of nesting marine turtles. Data collection from this season will be compared with the previous year’s collected data and added to the long-term monitoring of Jaguar predation on marine turtles in Tortuguero National Park. 2.3.
Methodology
Jaguar walks are conducted over the 14½ mile stretch of beach from the entrance of Tortuguero National Park (mile 3½) south to Jalova lagoon (mile 18). One to two GVI staff member and three to five Expedition Members conduct the survey once per week, starting from either Tortuguero or Jalova at dawn. General data such as date, name of researchers, weather, sand condition and start time is noted at the beginning of the survey. Beach size (distance from vegetation to high tide mark) is recorded every four miles (at mile 4, 8, 12 and 16) to give an indication of how much 1
beach was exposed during the previous night. Sand condition and general weather are also recorded every four miles. During the survey, researchers count the total number of fresh (1-2 nights old) turtle tracks on the beach, including both half moons (not nested) and full tracks (nested). When Jaguar tracks are encountered, the right hind foot is photographed and the length and width of the track are measured. The direction of the track (north or south) and location (mile marker and GPS coordinates) are also recorded. The track is then followed until it ends (goes into the vegetation or is washed away by the tide) and the mile marker and GPS coordinates are recorded again. As would be expected intense and prolonged rain, high winds and very dry sand, can reduce the quality of Jaguar prints making data collection very difficult. As weather conditions vary throughout the year it is possible data quality will be affected. In order to minimise this Jaguar surveys are undertaken during and after periods of optimal weather conditions where possible. Data on fresh carcasses of turtles killed by Jaguars is collected where possible. Data includes location (mile marker and GPS coordinates), species, point of attack, nights since kill, amount of meat eaten, location of carcass relative to the vegetation, whether the turtle is on its front or back, and any extra comments/observations. Photographs of particular features may be taken. 2.4.
Results
A total of 7 full surveys 1 were conducted between 3 February and 22 March 2006, with an average time of 9 hours and 20 minutes. A total of 31 surveys have been conducted by GVI since 11 July 2005. During Phase 3, two Green Turtles (Chelonia mydas) were killed by Jaguars (8 March and 22 March 2006). The number of separate sets of Jaguar tracks found during this phase was 39. A total of 67 Green tracks (full tracks 2: n = 37 and half moons: n = 30) and 21 Leatherbacks tracks (full tracks: n = 19 and half moons: n = 2) was recorded. The distribution of turtle and Jaguar tracks per mile and the location of the two turtle carcasses are shown in figure 2.1.
1
The total number of surveys was 8, but one (1) was aborted.
2
One ascending and one descending track independent of nest information; attempted nest or nest.
2
# 30 25 20 15 10 5 0 4 4/8
5
5 4/8
6
6 4/8
7
7 4/8
8
8 4/8
9
9 10 10 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 4/8 4/8 4/8 4/8 4/8 4/8 4/8 4/8 4/8
# jaguar set of tracks
Mile
# turtles tracks
Figure 2-1 Beach distribution of Jaguar and turtle track along the 14.5 miles in Tortuguero National Park. Period: 3 February – 22 March 2006. The symbol (
) represents the location of the
two turtle carcasses found during this period
In this phase, the highest concentration (more than 15 sets of tracks) of Jaguar tracks was between mile 7 and 13. The overall distribution of tracks and carcasses in
#
relation to date of survey is shown in figure 1.2.
70 60 50 40 30 20 10 0 3-feb
10-feb
17-feb
24-feb
Jaguar tracks
3-mar
10-mar
17-mar
Turtles tracks
Figure 2-2 Date distribution of tracks (Jaguar and Turtles) and turtle carcasses in Tortuguero National Park. Period: 3 February – 22 March 2006. The symbol (
) represents the date of the
two turtle carcasses found during this period (8 March and 22 March 2006)
2.5.
Discussion
Data collection during Phase 3 incorporates off season data (January and February) for Green and Leatherback Turtles and the beginning of the nesting season (March to July) for Leatherback Turtles. This information gives us a good picture of Jaguar
3
Date
presence on the beach of Tortuguero National Park during non-nesting and low density nesting periods. The presence of Jaguar tracks was registered in all the surveys. However, due to heavy rain washing out the tracks in the days before the survey, no data was collected on the size of tracks during the last survey on 22 March. The presence of tracks were recorded from mile 4 to 17 4/8, with an important concentration from mile 4 to 17 4/8 and in particular there seem to be two areas with a higher concentration from 7 4/8 to 8 and from mile 9 to 11. The two turtle carcasses located around mile 11 and mile 13 2/8 were found in the area of highest concentration of Jaguar tracks (> 15 sets of tracks). During Phase 3 there was evidence of Jaguar presence from all beach surveys. It therefore seems to indicate that Jaguars include this habitat in their home range during turtle non-nesting season and indeed most of the year (based on data collected by GVI since July 2005). Although the Green Turtle nesting seasons is recognised to begin on the 1st of June a few turtles came up the beach to lay eggs before this date (full tracks, n = 37). Two Green Turtles were recorded as being killed by Jaguars during Phase 3. It should be acknowledged however that although the Green Turtles came on to the beach outside of their nesting period it did fall within the nesting period of Leatherback Turltes. Currently there is insufficient data to support the theory that Jaguars’ foraging behaviour is directly correlated to marine turtle nesting seasons. Further long term research will help to identify any correlation that may be present and may possibly identify if there is an adaptive behavioural trait within the jaguar population, relating to turtles nesting. There are several hypotheses for jaguar presence on the beach, these include an increase in the jaguar population, deforestation forcing jaguars out on the beach and the decline in other prey species. At present none of the hypothesis can be supported or disproved (Troëng, 2000). The current method being used by GVI to distinguish between Jaguar prints involves comparison of print width and length. This method however is not ideal as track sizes can be statistically similar based on these two characteristics alone. Computer analysis of tracks enables up to 48 different measurements to be taken from each print. This increases significantly the statistical confidence with which it can be assumed a print belongs to a specific animal (Miller, 2001). However, accuracy of the basic width and length is still important and thus in order to minimise any error that 4
may occur during the measurement of Jaguar tracks, all future records will involve taking a minimum of 10 sets of track measurements where possible. From this a mean average print size can be calculated and used for analysis. The measurements of individual tracks seems to indicate that there may be different Jaguars in the two areas of high activity (from miles 7 4/8 to 8 and from 9 to 11). Most of the tracks found in the first half of the beach (closer to Tortuguero) were of a Jaguar with hind-foot prints of approximately 80mm x 100mm. This individual was usually found together with another individual with prints of about 80mm x 80mm. The second half of the beach was dominated by a larger Jaguar with hind-foot prints that measured 90mm x 110mm. However, this observation was more evident during Phase 1 (July – September), whereas the prints were more mixed in the two areas towards and after the end of the season (November - February). In addition, weather conditions and thus conditions of the sand make it very difficult to always obtain accurate measurements and good photos of the prints, so it remains a very biased assumption until more valid data supports this theory. Nevertheless, from the data collected so far, it is plausible to assume that there may actually be three different Jaguars walking on the beach in the Tortuguero National Park between mile 4 and 18. The print measurements could indicate a female with a one-year old cub usually in the area between mile 7 to mile 11. These two prints have been observed together many times. The second half of the beach has been dominated by larger Jaguar prints, possibly a male. The tracks from this individual have been recorded most frequently between miles 14 and 17, suggesting that the beach may have two separate Jaguar territories. In the beginning of Phase 1 this data proved consistent as only one size of prints were observed per area. In recent months (January – March) the ranges have been overlapping, and the larger Jaguar prints have been observed as far north as mile 7½ and two prints together (one larger than the other) as far south as mile 16½. Data from fresh turtle carcasses shows that the amount eaten by Jaguars is usually relatively small. They seem to kill the turtle, and then only eat a small amount of the internal organs (including the heart) found immediately below the fat layer. This could be due to the relative low energy expenditure of hunting turtles compared to hunting other prey like peccary (Tayassu spp.), deer or other mammals inside the forest (M. Castro, pers. comm.)
5
Continued data collection will help to improve this monitoring project and will provide a useful tool for the management and conservation of jaguars and turtles in the Tortuguero National Park.
3.
MARINE TURTLE MONITORING PROGRAMME
3.1.
Introduction
Tortuguero National Park was established in 1975 with the main purpose of protecting sea turtles and the nearby areas of humid lowland forest and beach (A. Castro, pers. comm.). The largest Green Turtle (Chelonia mydas) breeding colony in the Atlantic and the western hemisphere is situated in Tortuguero (Troëng, 2000). Over the past 20 years there has been a huge decline in both Leatherback Turtles (Dermochelys coriacea) (Troëng et al., 2004) and Green Turtles (Troëng & Ranking, 2005) due to overexploitation such as illegal harvesting of their meat and eggs, as well as fishing, contamination and habitat alteration. In addition to the general decline in marine turtles, Tortuguero and the surrounding area are continuously developing and thus the demand for protection and conservation of the marine turtles and their habitat is growing. Whilst the protection of wildlife in Tortuguero National Park is contributing to the stability of sea turtle populations, many beaches surrounding the park are supposedly undergoing a high percentage of poaching (J. Daigle, pers. comm.) In response to this, COTERC (Canadian Organization for Tropical Education and Rainforest Conservation) started a five-year long feasibility study in 2004 with the aim of determining nesting populations and poaching rates of Green and Leatherback Turtles on the North Beach. This beach which encompasses the study area is 31/8 miles long and extend from the Tortuguero river mouth (10º36’36,9”N 83º31’52,1”W) at the most southern point until Laguna Cuatro (10º37’56,3”N – 83º32’25,7”W) in the north. Although this beach is not within the Tortuguero National Park boundaries, it is situated within the Barra Colorado Wildlife Refuge, which is also managed by ACTo (Area de Conservacion Tortuguero) under MINAE – the Costa Rican Ministry for Environment and Energy. In July 2005 GVI joined COTERC in collecting data on the unprotected North Beach. As well as collaborating on the data collection and analysis, GVI and COTERC share data with the CCC (Caribbean Conservation Corporation) in order to increase the 6
available turtle data and compare poaching rates of turtles nesting on the National Park beaches. The project will be conducted during the main nesting season of Leatherback Turtles (March to mid-July) (Troeng et al., 2004), and that of Green Turtles (June to November). Data will also be collected during the nesting season for Hawksbill Turtles (Eretmochelys imbricata) and Loggerhead Turtles (Caretta caretta), which extends from June to September, but very few of these species are expected to nest on the North Beach. 3.2.
Aim
According to previous studies (conducted by COTERC) there is a great amount of illegal harvesting of turtle eggs, and to a lesser extent meat, on the North Beach. Thus, the aim of this project is to study the spatial and seasonal distribution of nesting females, the number of nesting emergences, illegal harvesting of turtle meat and eggs, and natural depredation of nests in order to study, monitor and protect the sea turtles coming to nest on the North Beach. 3.3.
Methodology
The methodology used for the marine turtle monitoring programme follows the COTERC and GVI protocol which is adapted from and approved by the CCC. 3.3.1.
Track and Nest Surveys
Each survey consisted of walking the beach between mile 0 and 3 1/8, recording tracks and nesting turtles during 5 hours (9 p.m. to 2 a.m.) for the night team and 2 hours in the morning (starting at 5.30 a.m.) for the day team. The teams identify tracks as full (turtle nested), half moon (turtle came out intending to lay but turned around before even attempting to nest), or a lifted/poached turtle (no tracks going back into the sea). Nests (full tracks) were then identified as either an attempted nest, a natural nest, or a poached nest. Data was also recorded from encountering dead turtles on the beach. The size, sex, state of the turtle, and an estimated time of death were recorded. Any obvious signs of an unnatural death were also recorded such as harpoon marks, machete cuts or blows to the head and/or limbs and photographs are taken. If the turtle had been tagged, the ID number was recorded and checked against CCC tagging data. 7
3.3.2.
Night surveys
The purpose of the night patrols was to collect data from as many turtles as possible. However, considering that the beach is 31/8 miles in length there was a possibility that not all turtles would be observed prior to or during nesting. If a turtle was not observed but the tracks were then standard track data was taken. Once there was confirmation of a nest (body pit and camouflaged egg chamber), it was investigated to identify whether the nest had been illegally harvested (signs of stick marks to find the egg chamber, exposed egg chamber or human foot prints), predated by animals or if remained in its original state. When encountering a turtle on the beach the following data was collected. •
The date and the time that the track was encountered
•
Time when the nesting process ended (if the turtle is encountered before going into the oviposition stage)
•
The initials of each member of the team
•
The mile marker number and GPS of each nest
•
The position of the nesting turtle (turtle facing North, South, East or West) when the turtle is laying eggs
•
The position of the nest on the beach in relation to the vegetation (in vegetation, close to vegetation or on open beach)
•
If the nesting process was observed a count of the number of eggs with yolk and yolkless eggs.
• 3.3.3.
Any other comments or anomalies observed Tagging
Female Leatherback Turtles were tagged on the membrane located between the tail and rear flipper using Monel (metallic) tags. Females were only tagged after having completed the nesting process, while they were covering the nest or returning to the ocean. Evidence of old tags in the flippers, old tag notches (OTN) or old tag holes (OTH) were also recorded as well as evidence of injuries or parasites. 3.3.4.
Biometric Data
For all the turtles encountered the minimum Curved Carapace Length (CCL) and the Curved Carapace Width (CCW) were recorded. Measurements were conducted by 8
two people and reviewed three times. Deformation or pieces missing of the carapace and flippers or any other relevant data was also recorded. 3.3.5.
Human impact data
Due to the recent increase in human activity on the North Beach all artificial light (white or red) observed during the night surveys was recorded. Number of people present and direction of travel was also recorded. 3.4.
Results
Data for Phase 3 was collected during the day between the 1st – 25th March (total: 25 days) covering the beginning of the Leatherback Turtle nesting season. Night surveys started on the night of 10th March, after two researchers from COTERC and GVI completed training provided by the CCC. During the daily track census a total of 812/8 miles (total: 37 hours 22 minutes) was walked, taking an average of 1 hour and 30 minutes to complete the 31/8 miles. Meanwhile, the nightly surveys covered 133 miles (total: 74 hours 16 minutes), taking an average of 5 hours to cover an average of 86/8 miles. 3.4.1.
Track census and nest surveys
All tracks encountered on the North Beach were identified as Leatherbacks. A total of 10 tracks were observed during the survey period divided into five nests and five half moons. The spatial and temporal distribution of activity is shown in figure 3.1 and 3.2.
9
LEATHERBACK TEMPORAL NESTING DISTRIBUTION IN NORTH BEACH 2006 3 2 1
Nest
23 -m ar
21 -m ar
19 -m ar
17 -m ar
15 -m ar
13 -m ar
11 -m ar
9m ar
7m ar
5m ar
3m ar
1m ar
0
Half Mon
LEATHERBACK SPATIAL NESTING DISTRIBUTION IN NORTH BEACH 2006 4 3 2 1 0 0
2/8
4/8
6/8
1
1 2/8 1 4/8 1 6/8 2
Nest
2 2/8 2 4/8 2 6/8 3
3 2/8
Half moon
Figure 3-1 and Figure 3-2 Temporal and spatial nesting distribution of total tracks (nests and half moons) for Leatherbacks (Dermochelys coriacea) on the North Beach during the first month of the nesting season in 2006.
3.4.2.
Monitoring of nests
60% of the nests (n = 3) seemed to be left in their natural state without any signs of poaching, erosion or predation. 20% (n = 1) of the total nests were poached based on various combination of evidence such as human foot prints, stick marks and / or an exposed egg chamber. Finally, it was not posible to determine whether the last 20% (n = 1) was poached or not, although there was evidence of stick marks and a deep hole in the sand which was not exactly where the egg chamber was located. 3.4.3.
Monitoring of female turtles
During three of the 15 days of night surveys, a Leatherback turtle was encountered nesting on the North Beach. The first female (No 1) was encountered during the process of covering her nest and it was not possible to count the eggs laid. The second female (No 2) was encountered during egg chamber excavation and the whole process of counting eggs, tagging and measuring took place. The third female (No 3) was encountered whilst covering her nest and thus it was not possible to go 10
through the normal process of counting eggs. These three turtles came out of the water to nest between the hours of 23:00 and 01:15. 3.4.4.
Tagging
Two of the three turtles (No 1 and No 3) encountered during this phase had already been tagged or had evidence of previous Monel tags (OTH). The second turtle encountered had no evidence of old tags and was thus tagged by the night survey team. See table 3.1 for more details. MONEL TAG's
OTN / OTH
Left
Left
Right
Right
CCL (cm)
CCW (cm)
Turtle No 1
VA1872
-
None
OTH
145
145
-
-
-
Turtle No 2
VA8206
VA8205
None
none
161
161 160,5 116 116,1 116
Turtle No 3
VA2494
VA2495
OTH
none
150
150 149,9 107
107
107
Table 3-1. Number of Monel tags, Details of previous and recent tags and measurements of carapace lenght and width from the turtles encountered during nesting on the North Beach, Tortuguero 2006.
All three turtles presented complete caudal projection and some small bites to the flippers. However, none showed any signs of deformation or any obvious disease. With respect to the position of the nest, all three turtles were found to nest in the open zone, a few metres above the high tide line. 3.4.5.
Biometry of female turtles
The counting of eggs was conducted once (Turtle No 2) and a total of 125 large eggs and 20 small eggs (infertile) were counted. The measurements of the carapace was 152 cm CCL and 111.5 cm, see table 3.1 for more detail. 3.4.6.
Human impact data
During the night surveys a minimum of 2 strong, white lights were observed at various times throughout the patrol. A total of 8 other white lights were observed from various locals or tourists passing by the survey team during a patrol. Only one red light was encountered during the night surveys when meeting a guide with a group of 20 tourists. In various places along the beach a few permanent lights from private houses have been observed, including a very bright external light on the top part of the beach in front of Turtle Beach Lodge. 11
3.5.
Discussion
Since the data collection from Phase 3 only covers the very beginning of the nesting season for Leatherback Turtles, there is only preliminary data from 3 worked turtles, and 25 day and 15 night surveys. In order to obtain better results from nesting female turtles, the aim of the project is to continue collecting data from the entire nesting season of both Leatherbacks and Green Turtles. Final results will be able to give an indication of nesting behaviour, nest success, and the level of poaching as well as comparing this data to future years of research.
3.5.1.
Track census and nest surveys
Five tracks out of the total 10 were recorded as nests and the other five were recorded as half moons, of which 2 presented a body pit and the initiation of egg chamber excavation. The reason why 50% of the turtles made half moons and went back into the sea without nesting could be various (Bjorndal et al., 1999) (due to physical state of the sand, state of the tide, lights, etc.) and perhaps at the end of the nesting season some factors which may have influenced it may be possible to identify this behavior. 3.5.2.
Monitoring of nests
At the moment it is not possible to determine if the nesting follows the Gauss curve (gradual increase in numbers of nesting turtles culminating in a peak at mid-season and then a gradual decrease towards the end of the season), but at the current rate it seems that 1-2 turtles are observed every 2.5 days of work. With respect to nests there has been one nest per five nights of surveys. From the limited data it seems that nesting is concentrated around mile 5/8 and 15/8. As previously mentioned, it is not possible to precisely know if out of the current five nests on the North Beach one or two are poached. Consequently, the poaching rate is somewhere between 20% and 40%, the remainder were left in a natural state.
12
3.5.3.
Tagging and monitoring of female turtles
All three females coming up the beach to nest were tagged, either previously (Turtle No 1 & 3) or by the COTERC/GVI team (turtle No 2). This tagging process will help determine nesting frequency and location of individuals and the interval between nesting events. 3.5.4.
Biometry of female turtles
Based on previous studies, the average number of eggs layed by a nesting Leatherback female is 82 normal sized and 30 infertile with a CCL of 154 cm. The turtle tagged on North Beach varied from these by laying 125 normal eggs, but only 20 infertile eggs and measuring 160.8 cm. These numbers and in particular the carapace length (CCL) seem to indicate that it was not a young adult, but instead an older female which has not been tagged during any of her previous nesting events. 4.
EBCP RESIDENT BIRD PROJECT
4.1.
Introduction
Although much research into the migratory avifauna of the New World has been conducted in Costa Rica, there is still much to be learned about the natural history of residential species. In collaboration with Steven Furino at Waterloo University, Canada, GVI is continuing to accumulate data on the presence of resident and migratory bird species and monitor their seasonal activity patterns in four different sites around the Estación Biológica Caño Palma (EBCP). Steven Furino has designed a programme, ‘WINGS’, in order to make this raw data available to fellow researchers and the general public. In addition, the data may also provide the Costa Rican Ministry of Environment and Energy (MINAE) with a management tool. 4.2.
Aim
The aim of this study is to collect presence data on local bird communities which can then be accessed and used for scientific research by anyone in the world. The data collected may help to identify changes in population trends, migration patterns and habitat usage and prove to become a useful management tool for MINAE and ACTo (Area de Conservación Tortuguero). 13
4.3.
Method
The bird project is conducted using two standard bird monitoring methods; Area Searches and Point Counts which are discussed below. For both survey types the ‘Widdowson Tortuguero Species Checklist’ for birds (Widdowson & Widdowson, 2004) is used to allocate an abundance rating to each bird species recorded. This rating is based on the probability of encountering the species in its preferred habitat in the appropriate season. This system is used to assess how many of the species recorded fall into the following categories: I.
Common; Easily seen most days, often in moderate to high numbers;
II. Fairly Common; Should be seen most days, in small numbers; III. Uncommon; Hard to see, only once or twice a week; IV. Rare; Very hard to see even in appropriate habitat and season; and V. X; Casual, vagrant, or few records; unlikely to see. Also includes species recorded but not on the Widdowson list. In order to achieve and maintain a high standard of data collection, expedition and staff members undergo continuous training on the research methodology and identification of study species. The identification of target species focuses on avian species, examining not only the study species but also those species that may be easily confused with any one of the study species. Appendix 1 contains a list of all the avian study species along with species they could be easily confused with. 4.3.1.
Point Count Method
Point Counts are undertaken at predetermined points within the four study sites. Within each study site there are six points except for Caño Palma where there are five Point Count stations. Dawn Point Counts and Area Searches are conducted between sunrise and 0930, and afternoon Point Counts and Area Searches between 1400 and 1700. Both Point Count and Area Search methods are used in the same four study sites around EBCP. These sites are: I.
CT - Cerro Tortuguero, the highest local point (119m). It possesses a terra firme forest different from the forest near the station. Its height also makes it a favourite spot for soaring raptors; 14
II. NB - North Beach, a 5 km section of sand beach from the mouth of Laguna de Tortuguero to Laguno Cuatro, providing a coastal habitat to study; III. CP - Caño Palma, a 5 km section of narrow canal from EBCP to the entrance to the canal to Laguna Cuatro,; and IV. CA - Cleared Areas, including the grounds of EBCP, the grounds of Cabinas Vista al Mar, and the barrio of San Francisco. When undertaking Point Counts surveyors record all birds seen and heard during a
S
H
S/ H
S
S/ H
H
S
H
S/ H
Notes
S/ H
Habitat (G,L,H,A)
H
Total #
S
>50
Unknown distance
Distance and Cue from point 10-25 25-50
0-10
name)
Species (common
Time observed
Station Code
ten minute period. For each record the following data is taken:
Table 4-1 Data collected during Point Count surveys
During the ten minute period surveyors must remain in the same location, only moving in order to obtain a positive identification. 4.3.2.
Area Search Method
Area Searches are within the same study sites as Point Counts however surveyors are recording data for twenty minute periods whilst moving. Twenty minute surveys are undertaken between predetermined points so as to allow for comparative analysis. Area searches can prove to be more useful for determining species
S/H
Table 4-2 Data collected during Area Searches
15
S
H
S/H
Notes (Male, Female)
H
Habitat (G,L,H,A)
S
Number off site Total # ind.
Species (common name) Species (scientific name)
Number on site Time observed
Station Code
composition within study sites.
4.4.
Results
A total of 110 different species were recorded during the Phase 3 survey period. Table 4-3 presents a breakdown of species abundance and Figure 4-1 shows the same data in graphical format. Abundance Common Fairly common Uncommon Rare
Number of species 69 19 16 3 3 110
X Total
Table 4-3 Species composition of birds, recorded during both Point Counts and Area Searches, based on abundance within the Tortuguero area
120
100
Number of species
80
60
40
20
0 species
common
fairly
uncommon
Rare
X
Figure 4-1 Species composition of birds, recorded during Point Counts, based on abundance within the Tortuguero area
Of the bird species recorded 62% were Common, 17% Fairly Common, 15% Uncommon, 3% Rare and 3% Casual, Vagrant or Few records. The three species recorded during the surveys as rare species within the Tortuguero area, were the Great Black Hawk Buteogallus urubitinga (North Beach), Cinnamon Woodpecker Celeus loricatus (Cerro Tortuguero) and Green Ibis Mesembrinibis cayennensis 16
(Caño Palma). The “X” species were Pomarine Jaeger Stercorarius pomarinus and Yellow-bellied Sapsucker Sphyrapicus varius, both which were recorded on North Beach, and White-lined Tanager Tachyphonus rufus recorded on Cleared Areas. 4.4.1.
Point Count Results
During the Phase 3 survey period a total of 106 different species were recorded during Point Count surveys. Table 4-4 presents a breakdown of species abundance and Figure 4-1 shows the same data in graphical format. Abundance Common Fairly common Uncommon Rare
Number of species 68 19 16 2 1 106
X Total
Table 4-4 Species composition of birds, recorded during Point Counts, based on abundance within the Tortuguero area
80
70
Number of species
60
50
40
30
20
10
0 common
fairly
uncommon
Rare
X
Figure 4-2 Species composition of birds, recorded during Point Counts, based on abundance within the Tortuguero area
Of the bird species recorded 64% were Common, 18% Fairly Common, 15% Uncommon, 2% Rare and 1% Casual, Vagrant or Few records. The two species recorded during Point Counts as rare species within the Tortuguero area, were the Great Black Hawk (North Beach) and Green Ibis (Caño Palma). The one “X” species recorded was the Pomarine Jaeger recorded on North Beach. 17
160
140
number seen/ number of records
120
100
Black Vulture Montezuma Oropendola Bright-rumped Attila Brown Pelican Keel-billed Toucan Semipalmated Plover Stripe-breasted Wren
80
60
40
20
0 CA most numerous
CA most frequent
CP most numerous
CP most frequent
CT most numerous
CT most frequent
NB most numerous
NB most frequent
Figure 4-3 Variation between number of birds and frequency of records during Point Counts
Figure 4-3 illustrates the variation in most numerous and most frequent 3 avian species recorded within each study site. On CA, CP and NB the two most frequent and most numerous birds were the same (Black Vulture Coragyps atratus and Montezuma Oropendola Gymnostinops montezuma on CA; Montezuma Oropendola and Bright-rumped Attila Attila spadiceus on CP; and Brown Pelican Pelecanus occidentalis and Semipalmated Plover Calidris pusilla on NB) however on CT this was not the case. On CT the two most numerous birds were the Brown Pelican and Keel-billed Toucan Ramphastos sulfuratus where as the most frequently recorded species were Keel-billed Toucan and Stripe-breasted Wren Thryothorus thoracicus.
3
Frequent refers to the number of records obtained for the species and numerous refers to
the number of that species recorded e.g. frequent: 10 records, numerous: 25 birds
18
120
100
% of birds
80
CA CP CT NB
60
40
20
0 total number of positive id
total number of family only
total number of Unknown
total number seen
total number heard
Figure 4-4 Variation in identification of species and comparison between seen and heard recordings during Point Counts
The total number of positively identified birds varied between 64% and 76.5%. Positive identification was most successful within the NB study site and least successful along CP. The percentage of birds that could not be identified to either species or family level varied between 3% and 10%. The percentage of ‘unknowns’ was greatest within the CP study site. Of the birds recorded the majority were seen, however the percentage of species seen against species heard varies between study sites. Within the CP and CT study sites the percentage of birds seen were 57% and 54%, respectively, whereas on CA and NB the percentage of birds seen were 86% and 96% respectively. 4.4.2.
Area Search Results Abundance
Number of species
Common
62
Fairly common
17
Uncommon
12
Rare
2
X
2
Total
95
Table 4-5 Species composition of birds, recorded during Area Searches, based on abundance within the Tortuguero area
19
100
90
80
number of species
70
60
50
40
30
20
10
0 species
common
fairly
uncommon
Rare
X
Figure 4-5 Species composition of birds, recorded during Area Searches, based on abundance within the Tortuguero area
Of the bird species recorded 65% were Common, 18% Fairly Common, 13% Uncommon, 2% Rare and 2% Casual, Vagrant or Few records. The two species recorded during Area Searches as rare species within the Tortuguero area, were the Cinnamon Woodpecker (Cerro Tortuguero) and Green Ibis (Caño Palma). The two “X” species were Yellow-bellied Sapsucker (North Beach) and White-lined Tanager (Cleared Areas). 300
number seen or heard/number of records
250
200 Black Vulture Variable Seedeater Great Kiskadee Western Slaty-Antshrike Stripe-breasted Wren Turkey Vulture Semipalmated Plover Brown Pelican
150
100
50
0 CA most numerous
CA most frequent
CP most numerous
CP most frequent
CT most numerous
CT most frequent
NB most numerous
NB most frequent
Figure 4-6 Variation between number of birds and frequency of records during Area Searches.
20
Figure 4-6 illustrates the variation in most numerous and most frequent avian species recorded within each study site. On CP, CT and NB Area Searches the two most frequent and most numerous birds were the same (Western Slaty-Antshrike Thamnophilus atrinucha and Stripe-breasted Wren on CP; Black Vulture and Turkey Vulture Cathartes aura on CP; and Brown Pelican and Semipalmated Plover on NB) however on CA this was not the case. On CA the two most numerous birds were the Black Vulture and Variable Seedeater Sporophila corvina where as the most frequently recorded species were Black Vulture and Great Kiskadee Pitangus sulphuratus.
120
100
% of birds
80
CA CP CT NB
60
40
20
0 total number of positive id
total number of family only
total number of Unknown
total number seen
total number heard
Figure 4-7 Variation in identification of species and comparison between seen and heard recordings during Area Searches.
The total number of positively identified birds varied between 71% and 90%. Positive identification was most successful within the NB study site and least successful along CP. The percentage of birds that could not be identified to either species or family level varied between 2% and 11%. The percentage of ‘unknowns’ was greatest within the CP study site. Of the birds recorded the majority were seen, however the percentage of species seen against species heard varies between study sites. Within the CP and CT study 21
sites the percentage of birds seen were 40% and 74% respectively where as on CA and NB the percentage of birds seen were 90% and 96% respectively. 4.5.
Discussion
The EBCP Resident Bird Project monitoring surveys began in July of 2005 and will continue for several years. As the study is only in its third phase, this early set of data can not be taken as indicative of trends for local bird species. The data collected in this third phase generally supports data collected in the previous two phases. The data confirms that the Cerro Tortuguero is the least species-rich site for avifauna, while the Cleared Areas sites support the highest species richness and remain the best site for relative abundance and diversity. The technique of using both Area Searches and Point Counts to conduct monitoring surveys works as an effective indicator to determine the local bird presence. The two survey techniques seem to generally yield a similar species list. The composition of species found within each study site has been based on all records. Although species were recorded as on or off site, early confusion on the correct definition of these terms has resulted in inconsistent data collection. In order to overcome this issue, to some extent species were analysed based on the number of times they were recorded and the number of individuals 4 recorded. Analysis of both Point Counts and Area Searches indicates that the second most numerous species was generally the best example of significant species for that habitat. Large flocks of pelicans and vultures tended to skew the results. The top two most numerous and common species tended to be the same within sites and survey technique. When species composition was compared between survey technique and study site there was a distinct difference. Although it is difficult at this stage to confirm any reason for this, it appears that small and more audible species were detected during the Area Searches, where as on the Point Counts the larger visual species were recorded.
4
It is recognized that where the term “individual” is used that these do not necessarily refer to different
birds within the population, however for the analysis no differentiation is possible.
22
The overall numbers of rare species is expected to increase as the project becomes more established. Not only will the surveys cover a longer period of time, but the survey techniques are expected to improve along with the training of expedition members and therefore more birds should be identified based on hearing calls/songs as well as by sight. The Tortuguero area offers great opportunities to find rare and accidental species due to its remote location and undisturbed habitats. The location is also an important area for migrating birds and is connected with the Barra Colorado Wildlife Refuge and the large Indio-Maiz National Park in Nicaragua. During Phase 3 a relatively high proportion of X, Rare and Uncommon species were recorded during surveys. This is a promising sign that surveys are being conducted to a high enough standard for these more unusual species to be positively identified. The fact that birds still being identified to only family level or recorded as unidentified, indicates that birds are not being “guessed” where surveyors are not 100% sure of the species these categories are used. The EBCP Resident Bird Project surveys undertaken during Phase 3 have assisted in increasing the overall data set. They have also helped in identifying areas where continued improvement to the methodology is required in order to gain the most useful and accurate data possible. A new key species list will be developed for Phase 4 that will include migratory species in addition to those which are typical of the selected habitats. It will be important that the species list is concise in order to facilitate training and data collection. It must be acknowledged that the aim of the study is to monitor changes in species and not to create a new species list for the Tortuguero area. 5.
NATIONAL PARK TOURIST IMPACT ASSESSMENT
5.1.
Introduction
Tortuguero National Park was created in 1975 in order to protect the large diversity of wildlife that exists within it. The park is managed and protected by the Costa Rican Ministry of Environment and Energy (MINAE). Terrestrial sections of the park consist of primary rainforest and flooded swamplands, which extend from the Caribbean coastline to the foothills of the central Costa Rican mountain range. Aquatic sections of the park include navigable lagoons, canals, and waterways. Terrestrial and aquatic trails are clearly marked and allow tourists the opportunity to experience the impressive species richness of the area; 2200 species of plant, 375 bird species, 125 23
mammal species and 124 species of reptiles and amphibians exist within the park’s boundaries (Bermúdez & Hernández, 2004). The flow of tourists to the national park is regulated by MINAE; however, rising tourist numbers could increase the pressure to the area. Greater accessibility to this region has begun produce a constant influx of groups of tourists using both the aquatic and terrestrial trails. Eco-tourism is encouraged, however it is essential that a certain balance between the park’s human activity and use and the conservation of these fragile ecosystems should be respected (Bermúdez & Hernández, 2004; C. Calvo, pers. comm.). However, there is a potential threat to the biodiversity of the park due to excessive stress from continuous human activity. In the last 15 years, annual totals of visitors to the park have risen from 9,000 to more than 70,000. 5.2.
Aims
Funded by the European Union, in 2005 MINAE developed a Management Plan for Visitors to Tortuguero National Park. However, due to lack of human resources, MINAE requested the assistance of GVI to initiate and implement the Tourism Impact Assessment in order to provide data for an objective and quantitative evaluation of the impact of Tourism in Tortuguero National Park (Bermúdez & Hernández, 2004). The aim of the National Park Tourist Impact Assessment is to document and monitor species abundance and diversity in relation to presence of human activity. The ongoing collection of this data is being documented by GVI in conjunction with MINAE, to accurately assess the degree to which tourists are influencing the park’s biodiversity. The commencement of this data collection was initiated in November 2005 by GVI. This baseline data is essential in order to generate a good understanding of the ecological systems operating in and around the park. As this understanding continues to develop, methodology is adapted to yield the most beneficial results possible. 5.3.
Methods
The National Park Tourist Impact Study consists of three separate research areas, these are: I.
Aquatic Survey; 24
II. Terrestrial Survey; and III. Strawberry Poison Dart Frog Transect. The data obtained from these three research areas assists in the establishment of creating a realistic view into what is happening within the park both on an ecological level and a tourist impact level. 5.3.1.
Aquatic Trails
This part of the study involves surveying two aquatic transects within the National Park; Caño Harold and Caño Chiquero. Transects are conducted between 05:40am and 06:50am on a weekly basis for both Caño Harold and Caño Chiquero. Caño Harold is also surveyed before dusk, commencing at between 13:50 and 15:00. Up to six researchers record avian, reptilian and mammalian species activity using the following data categories: Sector
Time
Species
# Cue
On/Off
Habitat
Notes
Site Figure 5-1 Data categories for aquatic survey.
Each study site has been divided into sections to aid with data recording and analysis. Caño Harold is divided into four sections whilst Caño Chiquero is divided into five sections. AC1 and AC2 (Access 1 and 2) form the first two sectors of either Caño Harold or Chiquero and are thus surveyed during every aquatic survey. The beginning of AC1 is located at the start of Rio Tortugero and continues along the Caño until it reaches the westerly Caño which leads to both Caño Harold and Chiquero. At this point AC2 begins and continues in a westerly direction towards Caño Harold. Where Caño Harold enters AC2, CH1 (Caño Harold 1) begins. CH1 continues up Caño Harold leading into CH2 and CH3 along the way. The survey of Chiquero continues past Caño Harold along AC2. Where AC2 leads into Caño Chiquero, CC1 (Caño Chiquero 1) begins. The transect continues up along the Caño and becomes sector CC2. When a species is observed, a record is made of the sector in which it is located including the time of sighting, the species, number of individuals, cue (whether seen and / or heard), the location (on or off site) and the position within the habitat (Ground Level, Low Level, High Level and Aerial). Points of interests include; behavior, sex and stage are recorded in the notes. 25
The non-avian target species for the aquatic surveys include the Spider Monkey Ateles geoffroyi, Black River Turtle Rhinoclemmys funerea, and Spectacled Caiman Caiman crocodiles. The avian target species are the Anhinga Anhinga anhinga, the Green-backed Heron Butorides virescens, the Cormorant Phalacrocorax brasilianus and all Kingfishers (family Alcedinidae). However, all individuals encountered are identified to species level where possible; where this cannot be achieved family name is recorded. Occasionally it is not possible to obtain either of these categories so the individual is recorded as unknown. Tourist activity is also recorded during each survey, information on number of visitors and the type or name of boats seen (eg. Canoe, Laguna Lodge, no motor, electric motor, 4-stroke motor) is recorded. Individual boats are recorded only once per survey. 5.3.2.
Terrestrial Trail
The Sendero Gavilán is a terrestrial loop trail, 1.920 meters long, located immediately south of the Park Head Office, Cuatro Esquinas. Up to four researchers commence survey at Cuatro Esquinas, and walk counterclockwise around the trail. Data is collected using the same methodology as with the aquatic survey. The only target species for the terrestrial trail are Spider Monkeys Ateles geoffroyi and Strawberry Poison Dart Frogs Dendrobates pumilio, but data is also collected from other mammal and avian species.
The trail is broken into four sectors: I.
G1 – Trail head to 550 meters;
II. G2 – 550m to 1100m (at the path parallel to the beach); III. G3 – 1100m to 1500m (the trail parallel to the beach); and IV. G4 – 1500m (the water tower) to the trail head. 5.3.3.
Strawberry Poison Dart Frog (Dendrobates pumilio) transects
Presence/absence data is collected on Strawberry Poison Dart frogs along two transects cut west (100m from Sendero Gavilán) and south (500m from Sendero
26
Gavilán) of the trail. This frog species, D. pumilio, is believed to have declined possible to the point of local extinction within this area of the national park. 5.4.
Results
The following results highlight the main findings from the research undertaken during phase 3. Data has been analyzed based on the quantity available to produce sound results. Some areas of study will require further research in order to be assessed adequately. 5.4.1.
Aquatic Trails
The two Aquatic Trails were surveyed 24 times during the course of Phase 3, which means that Access 1 and 2 (AC1 and AC2) were surveyed a total of 24 times. However, Caño Harold was surveyed 18 times, 12 of which were dawn surveys. Caño Chiquero was surveyed 6 times, all of which were dawn surveys. The average time taken to complete surveys on Caño Harold was 1.38 hours, whilst Caño Chiquero took an average of 1:15 hours. The average time spent on both aquatic surveys within the national park was 1:33 hours. The average number of records collected on both surveys was 66. On Caño Harold surveys alone the average was 71 and for Caño Chiquero the average was 51. The average number of birds recorded on both surveys was 81. On Caño Harold surveys alone the average was 87 and for Caño Chiquero the average was 65. Figure 5-2 illustrates the percentage difference of the individual Caño compared to the average of both surveys combined.
27
10
% mean difference from combined mean
5
0 Time spent surveying
Number of records
number of birds
-5 Cańo Harold Cańo Chiquero -10
-15
-20
-25
Figure 5-2 Mean percentage difference for combined mean percentage difference for time, number of records and number of birds
The average number of records collected per minute and birds seen per minute are 0.72 and 0.89 on Caño Harold, respectively, and on Caño Chiquero they are 0.68 and 0.87. This data indicates that there is no significant difference in the number of records collected or the number of bird species recorded between the Caño. However when the bird assemblages are examined there is a clear difference in the species present in the various Caño.
28
Most common birds in AC2
Most common birds in AC1 Common name
Latin name
Little Blue Heron Montezuma Oropendola Bare-throated Tiger-Heron
Egretta caerulea Gymnostinops montezuma Tigrisoma mexicanum
Snowy Egret Western SlatyAntshrike Chestnut-backed Antbird
Egretta thula Thamnophilus atrinucha Myrmeciza exsul
Number seen
Common name Montezuma Oropendola
117 45
Little Blue Heron Bare-throated Tiger-Heron Short-billed Pigeon
33 26 16
Sungrebe Stripe-breasted Wren
15
Most common birds in CC Common name
Latin name
Little Blue Heron Montezuma Oropendola Western SlatyAntshrike
Egretta caerulea Gymnostinops montezuma Thamnophilus atrinucha
Sungrebe Stripe-breasted Wren Chestnut-backed Antbird
Heliornis fulica Thryothorus thoracicus Myrmeciza exsul
Latin name Gymnostinop s montezuma Egretta caerulea Tigrisoma mexicanum Patagioenas nigrirostris Heliornis fulica Thryothorus thoracicus
Number seen 35 26 8 7 7 6
Most common birds in CH Number seen
Common name Little Blue Heron Green-backed Heron
31 16 9
Snowy Egret Bare-throated Tiger-Heron Short-billed Pigeon Western SlatyAntshrike
7 6 6
Latin name Egretta caerulea Butorides virescens Egretta thula Tigrisoma mexicanum Patagioenas nigrirostris Thamnophilus atrinucha
Number seen 138 88 42 38 38 36
Table 5-1 Comparison of the six most common bird species found within the different study areas
The Little Blue Heron Egretta caerulea was the most common bird species recorded on three of the four Caño sectors. The variation between species composition increases when the 2nd to 6th most common species are examined. In addition to the avian records, data was also collected on the presences of other families, the following were all recorded during aquatic surveys: Mantled Howler Monkey Allouata palliate, Spider Monkey Ateles geoffroyi, White-faced Capuchin Cebus capucinus, Monkey Cebidae sp., Black River Turtle Rhinoclemmys funerea, Spectacled Caiman Caiman crocodilus, Neotropical River Otter Lutra longicaudis, Dolphin Delphinidae, Bat Chiroptera ord., Basilisk Basiliscus sp., Iguana Iguana iguana, Lizard Norops sp.. Figure 5-3 shows the number of individuals of the top six species recorded on the aquatic survey.
29
120
100
number seen/heard
80
60
40
20
0 Mantled Howler Monkey
White-faced Capuchin
Spider Monkey
Neotropical River Otter
Black River Turtle
Spectacled Caiman
Figure 5-3 Quantity of the top six non-avian species recorded during aquatic surveys
CH
CC Mantled Howler Monkey White-faced Capuchin Spider Monkey Neotropical River Otter Black River Turtle Spectacled Caimen AC2
AC1
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
% of individual species
Figure 5-4 Distribution of non-avian species within Aquatic Study site
The data collected on non-avian species illustrates that Mantled Howler Monkeys are the most common non-avian species within all Caño sectors except Caño Harold where the most common species was Spider Monkey.
30
5.4.2.
Terrestrial Trail
The terrestrial trail Sendero Gavilán was surveyed eight times during Phase 3 in the morning hours, starting before or at 06:30, for an average of 1:49 hours per survey. 52% of recorded species were noted in sector G1, 19% in both G2 and G3, and the remaining 10% of recorded species were seen in sector G4. 73% of all recorded animals were birds, 23% mammals, 3% reptile and 1% amphibians throughout the Gavilán.
140
120
number seen or heard
100
Amphibian
80
Bird Mammal Reptile
60
40
20
0 G1
G2
G3
G4
Sector
Figure 5-5 Number of individuals recorded per trail sector
5.4.3.
Strawberry Poison Dart Frog (Dendrobates pumilio) Transects
The two transects were sampled eight times during Phase 3. No Dendrobates pumilio were recorded, however, two Tree Climbing Toads Bufo coniferus, one Veined Tree Frog Hyla phlebodes and a Gulf Coast Toad were all positively identified during the surveys. 5.5.
Discussion
Although methodologies have been identified, the data collected is at the preliminary stage, where further modifications and increased data samples are necessary. 31
All target species sightings (birds, reptiles and mammals) were recorded on the surveys and data on visitor numbers and transport mode was also recorded. This is very important and quantifiable data which is necessary to properly assess the impact tourist presence is having on wildlife within the Park. However, current sample sizes are too small at the moment and more data should be collected before any indepth analysis can take place. From the data collected during this phase of the study some preliminary conclusions can be presented. 5.5.1.
Aquatic Trails
The data colleted from the Aquatic Trails indicates the unit effort is constant throughout the survey period. This factor eliminates any effort biases that may occur due to different surveyors undertaking the research at different times. This unit effort should be monitored during future phases to ensure it remains constant in relation to the survey technique. Analysis of the data indicates possible patterns in relation to bird assemblages within the different Caños of the study site. Although the volume of data collected between Caño Harold and Caño Chiquero were very similar, there were distinct differences in the species recorded. Further data collection will help to confirm this pattern, whilst analysis of other variable will be helpful to find why this difference is occurring. The data collected on the Aquatic Trail illustrated that of the aquatic species recorded, the herons, egrets and Sun Grebes were the most common. The other species recorded as the most common species were all very auditable species and not necessarily good indicators of the Caño habitats. The non-avian species recorded varied distinctively between Caños. For example AC1 had the largest number of Mantled Howler Monkeys recorded whereas Caño Harold had the highest number of Spider Monkeys. Consistently large numbers of Mantled Howler Monkeys were recorded. A significant proportion of these records were obtained on audio bases and due to the nature of the species they are considerably more audible then any other non-avian species within the study. The number of other non-avian species recorded does not necessarily refer to quantity within the area but may be an indication of ease of viewing. Adjustments to the methodology based on data collected to date will enable a more accurate picture of both species abundance and area usage within the National Park. 32
5.5.2.
Terrestrial Trails
The Terrestrial Trail within the National Park have provided some interesting results during this phase. The difference in species composition and abundance is the most obvious area to examine. There are three distinct areas based on the aforementioned factors; G1, G2 & G4 and G3. G1 was the most abundant and species-rich area, being the only area where amphibians, reptiles, mammals and birds were all recorded. On G2 and G4 birds, mammals and reptiles were all recorded and on G3 only birds and mammals were recorded. These variations could be due to a variety of variables that if deemed necessary could be investigated at a later date. An interesting factor that can be extracted from this data is the presence of amphibians only in G1. It could be speculated that it is because amphibians are more likely to be present in the area closer to the river than to the beach, and that a transect closer to the river but further away from the trail would be worth considering for the Strawberry Poison Dart frogs transects. 5.5.3.
Strawberry Poison Dart Frog Transects
The absence of Strawberry Poison Dart frogs is not surprising as there is a general consensus in Tortuguero and with the National Park staff at Cuatro Esquinas that this species has not been observed in the last 4–10 years. The surveys have been undertaken over three phases to date with no positive record of Strawberry Poison Dart frogs. The preliminary conclusions at this point of the study would indicate that no Strawberry Poison Dart frogs have been recorded within the areas currently being surveyed.
6.
TOURIST IMPACT SURVEY CAÑO PALMA
6.1.
Introduction
Caño Palma is located within the Barra Colorado Wildlife Refuge, immediately north of the river Petenencia, about 7 km northwest of Tortuguero village and National 33
Park. Although not part of the National Park, this caño is included in the Management Plan for Visitors as it provides a suitable alternative for wildlife viewing to the National Park and thus helps to reduce the demand on the other caños (Bermúdez & Hernández, 2004). Proposed restrictions on the number of boats allowed into the National Park are due to be put in place at the end of April 2006. This is likely to increase the number of tourist boats using Caño Palma, and baseline data before this occurs is thus necessary. 6.2.
Aims
GVI has initiated the Tourist Impact Survey Caño Palma in order to estimate the intensity of the tourist activity and assess any change to species composition which could be directly related to the change in volume of usage on the Caño. 6.3. 6.3.1.
Methods Aquatic Trails
The aquatic surveys along Caño Palma are commenced between 05:30am and 06:30am or before dusk in the afternoon. Up to six researchers record avian, reptilian and mammalian species activity using the following data categories: Sector
Time
Species
# Cue
On/Off
Habitat
Notes
Site Figure 6-1 Data categories for aquatic survey
The study site has been divided into 5 sections (CP1 – 5) to aid with data recording and analysis. When a species is observed, a record is made of the sector in which the researchers are located, the time of sighting, the species, number of individuals, cue (whether seen/heard or seen and heard), the location (on or off site) and the position within the habitat (Ground Level, Low Level, High Level and Aerial). Any points of interests including; behavior, sex and stage are recorded in the notes. All individuals are identified to species level where possible; where this cannot be achieved family name is recorded. Occasionally it is not possible to obtain either of these categories so the individual is recorded as unknown.
34
Tourist activity is also recorded during each survey, information on number of visitors and the type or name of boats seen (eg. Canoe, Laguna Lodge, no motor, electric motor, 4-stroke motor) is recorded. Individual boats are recorded only once per survey. 6.3.2.
Boat Dock Survey
The Boat Dock Survey is commenced at 06:00 and continues for 12 consecutive hours. During the survey data is collected on all boats passing the boat dock. For each craft observed the following data is collected: I.
Time of observation
II. Number of passengers on each boat III. Boat name IV. Boat direction V. Time spent on canal VI. Engine type Any additional information that is considered to potentially be of use at a later date is recorded in notes. 6.4. 6.4.1.
Results Aquatic Trails
A total of 20 hours and 50 minutes was spent undertaking the aquatic surveys on Caño Palma. This consisted of 9 surveys between the 30 January and 20 March 2006. Of these 9 surveys one 5 has been excluded in the analysis of mean average data presented in figure 6- 2 because the data was collected in adverse weather conditions.
5
Data excluded from this section was gathered on 14th February.
35
3
2.5
number seen or heard
2
CP NP
1.5
1
0.5
0 average number of records per minute
average number of birds per minute
Figure 6-2 Comparison of mean average data from National Park and Caño Palma
The data in figure 6-2 shows that the mean average rate of records per minute is considerably higher in Caño Palma than within the National Park. The species that are most commonly recorded are also very different from any of the National Park Caños. Figure 6-3 illustrates the top 6 avian species recorded.
60
50
number seen or heard
40
30
20
10
0 Stripe-Breasted Wren
Montezuma Oropendola
Bright-rumped Attila
Western Slaty-Antshrike
Short-Billed Pigeon
Chestnut-backed Antbird
Figure 6-3 Top 6 avian species recorded on Caño Palma
Non-avian species were relatively infrequent during the surveys with Mantled Howler Monkeys being the most common species recorded. As with the National Park, a significant proportion of these were audio records (9 out of 25). 36
6.4.2.
Boat Dock Survey
A Tourist Impact Survey was carried out from the boat dock of Estación Biológica Cano Palma (EBCP), for twelve hours (during the hours of 06:00 to 18:00) on five separate days. Based on the limited data collated to date, the mean daily average of boats passing the station was 38.2. Laguna Lodge, Turtle Beach Lodge, Mawamba Lodge and Pachira Lodge were the most frequently observed tourist boats on Caño Palma. A significant proportion of the boats using Caño Palma can be attributed to these four lodges. 6.5.
Discussion
The Tourist Impact Survey Caño Palma has been in operation for one phase. In this time only a limited data set has been gathered. From this information only limited results can be extracted. As the data set expands with further data collection, a clear picture of localized tourist impact will become apparent. 6.5.1.
Aquatic Trails
The data gathered during the Aquatic Survey indicates that Caño Palma has a higher level of avian species abundance than the surveyed areas within the National Park. Based on this it would seem logical that it would be more appealing to tourists, however the top species composition consists almost entirely of species identified through calls only. This factor instantly reduces the value to Caño Palma to tourist in comparison to the National Park. The low number of heron and egret species compared to the National Park could be attributed to a number of factors, including level of disturbance, habitat type and water quality. Further research into these factors will help to identify possible reasons for the difference in species composition.
37
6.5.2.
Boat Dock Survey
The initial finds from the first phase of research in to this study have provided the study with baseline data. At present only 5 data sets have been obtained, therefore it is difficult to draw any sound conclusions from the data at present. As the data set increases so will its value and therefore long term analysis will be possible. The survey work undertaken in Phase 3 will be used to modify the methodology in order to gather the most relevant data required.
38
7.
COMMUNITY WORK
7.1.
Introduction
People of different nations increasingly utilize English as a common language in order to communicate with one another. Costa Rica, and in particular Tortuguero, hosts a growing number of international visitors each year. The people living in this area rely heavily on the international community and the tourism market. Acquisition of English language skills is one tool for accessing this market. GVI uses the teaching/learning theories and methodologies used by the TEFL Program (Teaching English as a Foreign Language). 7.2.
Aims
The following are the main aims of the teaching programme: I. Local community training/capacity building. II. Increase sustainable revenue to the local communities. III. Generate local community commitment to environment conservation and sustainable development. IV. Language and Cultural Exchange. V. Provide authentic opportunities for local students to practice listening and speaking English with native speakers. VI. Provide an introductory course in the methodology of TEFL for Expedition Members. 7.3.
Method
GVI, in collaboration with the local Peace Corp, conducted English lessons twice a week in the Village of Tortuguero for one hour each, for four weeks, from January 30th through February 25. The following 4 weeks, GVI taught English classes in the adjacent community of San Francisco. Throughout the 8 weeks, simultaneous Language / Cultural exchanges, or Inter-cambios, were scheduled in both San Francisco and with the Tortuguero National Park Rangers. The English lessons were created, written and adapted to fit the proficiency, the desired content, and the comfort level of the students and the teachers. Preparing and teaching in teams of two, Expedition Members had the opportunity to share ideas and work together. Each pair of teachers had a group of 3-5 students, who had comparable language skills. Planning took place in the afternoons and teaching in the evenings. The lessons focused mostly on oral skills rather than written work.
39
7.4.
Results
Along with two Peace Corp Volunteers, 8 GVI teachers taught 20 students in Tortuguero for a total of 8 contact hours. The average teacher: student ratio was 1:2. 12 GVI teachers conducted 8 hours of Language classes for 30 adult students and 18 children from the community of San Francisco. Average teacher: adult student ratio 1:2, teacher: child student ratio 1:7. GVI has continued the commitment to offer the adult English language programme in San Francisco during Phase 3, and GVI has also maintained support for the children’s programme supporting the national curriculum and local primary school. During Phase 3 GVI continued the Inter-cambio programme (a language and cultural exchange programme) between 12 Expedition Members and 4 Costa Rican citizens up to twice a week. The information exchange took place for a total of 55 hours. All Expedition Members received fundamental training in teaching English as a foreign language utilizing the TEFL system. 7.5.
Discussion
Phase 3 ended with the successful completion of 70 teaching contact hours among a total of 16 GVI teachers and 72 students. The atmosphere was relaxed and fun, but. the participants worked very hard and are extremely grateful to GVI for receiving the lessons. The lessons were given and received with great enthusiasm. When polled, our students overwhelmingly responded that their reason for learning English is to help them obtain jobs in the tourism industry. Students are keen to learn English and thus increase personal capacity building in order to improve chances of getting work or a better job within the thriving tourism of Tortuguero. The community of San Francisco is also generally interested in GVI’s presence and work in the area, and the meetings have built friendships and mutual respect.
40
8.
SUMMARY CONCLUSION
Phase 3 of the Costa Rican Rainforest and Wildlife Conservation Expedition has been successful in continuing the collection of scientific data from the 4 established biological projects. Data for the monitoring of Jaguar predation on marine turtles has continued for MINAE in this third phase. Although this period covers the non-nesting and low density nesting periods, it seems that Jaguar presence on the beach of Tortuguero National Park is still strong. In partnership with COTERC, GVI has continued the monitoring programme of marine turtles on the North Beach in order to gain more knowledge from tagged turtles and compare poaching rates of turtles nesting on protected National Park beaches. The programme involves track census and monitoring and tagging of nesting females was begun this phase. The ultimate aim is to support future protection and conservation of marine turtles nesting on the North Beach of Tortuguero. GVI has continued to collect data for the Resident Bird Project in association with Steven Furino of Waterloo University, Canada. The methodology for collecting data follows the protocols of Area Search and Point Counts techniques. The target species list has been revised and the bird identification training has been expanded. This focus on target indicator species has qualitatively improved the data collection. The Tourist Impact Assessment project in Tortuguero National Park has been successful in collecting preliminary data from the aquatic trails Caño Harold and Caño Chiquero, as well as the terrestrial trail Sendero Gavilán. Further modifications and increased data samples are necessary along with continued correspondence with MINAE.Additionally, during phase 3, GVI collected data on target species and tourist boat activity in Caño Palma. Community work has played an important part of the expedition as it is in high demand from the local communities and very enjoyable for Expedition Members. A 4week course in English language lessons for adults was conducted at Laguna Lodge in collaboration with the Peace Corp during the first half of the phase. In the second half of the phase, we returned once more to San Francisco, where English lessons were given to adults and children with much joy and success. An “Introduction to 41
TEFL” course was introduced in Phase 3 with the aim of better preparing the Expedition Members for teaching English successfully. Inter-cambio - cultural and language exchange opportunities – have again been highly successful. In addition to the two staff at Cabinas Vista al Mar, GVI has commenced Inter-cambio sessions with the staff at Tortuguero National Park. These sessions have been very positive and popular. Finally, the third expedition phase has been very successful. The 4 biological projects are becoming well established and the community work is taking shape and becoming an integral part of the expedition. Our partnership with MINAE and COTERC is becoming stronger through the relevant projects and in this way GVI Costa Rica continues to provide valuable data and support to conservation goals of the Tortuguero Conservation Area.
42
9.
Bibliography
Autar, L. 1994. Sea turtles attacked and killed by Jaguars in Suriname. Marine Turtle Newsletter 67:11-12. Bermúdez, F. A. & Hernández, C. A. 2004. Plan de Manejo para los Visitantes al Parque Nacional Tortuguero. Ministerio del Ambiente y Energía Sistema Nacional de Areas de Conservación Area de Conservación Tortuguero. 113 pages. Bjorndal, K.A., Wetherall, J. A., Bolten, A. B., & Mortimer, J. A. 1999. Twenty-Six Years of Green Turtle Nesting at Tortuguero, Costa Rica: An Encouraging Trend. Conservation Biology 13 (1): 126-134. Chacón, D., Valerín, N., Gamboa, H. & Marín, G. 1999. Manual de mejores prácticas de conservación de las tortugas marinas en Centroamérica. P.19. Miller, C. M. 2001. Measurement of Jaguar Tracks: a promising means to identify individuals, Track Collection Protocols, Belize. Troëng, S. 2000. Predation of green (Chelonia mydas) and Leatherback (Dermochelys coriacea) turtles by Jaguars (Pantera onca) at Tortuguero Nacional Park, Costa Rica. Chel. Cons. Biol. 3 (4):751-753. Troëng, S., Chacón, D. & Dick, B. 2004. Possible decline in Leatherback Turtle Dermochelys coriacea nesting along the coast of Caribbean Central America. Oryx, 38 (4), 395 - 403. Troëng, S. & Rankin, E. 2005. Long-term conservation efforts contribute to positive Green Turtle Chelonia mydas nesting trend at Tortuguero, Costa Rica. Biological Conservation, 121, 111 - 116 Widdowson, W. P. & Widdowson, M. J. 2004. Checklist to the Birds of Tortuguero, Costa Rica. Caribbean Conservation Corporation, San Jose, Costa Rica.
43
APPENDIX Appendix 1. GVI Costa Rica Key Avian Species List
Beach and near-shore waters Fresh water: canals, lagoons & marshes
cont.
1
Rufescent Tiger-Heron
46
Collared Plover
2
Bare-Throated Tiger Heron
47
Wilson´s Plover
3
Yellow-crowned Night-Heron
48
Killdeer
4
Green Heron
49
Black-bellied Plover
5
Little Blue Heron
6
Great Blue Heron
7
Boat-billed Heron
50
White-crowned Parrot
8
Tricolored Heron
51
Red-lored Parrot
9
Agami Heron
52
Mealy Parrot
10
Anhinga
53
Brown-hooded Parrot
11
Great Egret
54
Orange-chinned Parakeet
12
Cattle Egret
55
Olive-throated Parakeet
13
Snowy Egret
56
Crimson-fronted Parakeet
14
Osprey
15
Ringed Kingfisher
16
American Pygmy Kingfisher
57
Squirrel Cuckoo
17
Belted Kingfisher
58
Mangrove Cuckoo
18
Green Kingfisher
59
Long-billed Hermit
19
Amazon Kingfisher
60
Band-tailed Barbthroat
20
Green-and-rufous Kingfisher
61
Great Kiskadee
62
Boat-billed Flycatcher
Forest, including swamp & terra firme
63
White-ringed Flycatcher
21
Broad-winged Hawk
64
Gray-capped Flycatcher
22
Double-toothed Kite
65
Social Flycatcher
23
Collared Aracari
66
Tropical Kingbird
24
Keel-billed Toucan
67
Eastern Kingbird
25
Chestnut-mandibled Toucan
68
Clay-coloured Robin
26
Rufous-tailed Hummingbird
69
Rufous Mourner
27
Green-breasted Mango
70
Dusky Antbird
28
Blue-throated Goldentail
71
Passerini´s Tanager
29
Cinnamon Hummingbird
72
Blue-grey Tanager
30
Pale-billed Woodpecker
73
Palm Tanager
Clearings
Clearings continued
44
31
Lineated Woodpecker
74
Olive Tanager
32
Northern Barred-Woodcreeper
75
Scarlet-rumped Cacique
33
Streak-headed Woodcreeper
76
Olive-backed Euphonia
34
Plain-brown Woodcreeper
77
Yellow-crowned Euphonia
35
Wedge-billed Woodcreeper
78
Blue-black Grassquit
36
Black-striped Woodcreeper
79
Variable Seedeater
37
Bright-rumped Attila
80
Thick-billed seed-finch
38
White-collared Manakin
81
Montezuma Oropendola
39
Red-capped Manakin
40
White-ruffed Manakin
Aerial
Beach and near-shore waters
82
Black Vulture
83
Turkey Vulture
41
Neotropic Cormorant
42
Brown Pelican
Note: Species in the above table that
43
Common Black-Hawk
are presented in normal text are Key
44
Great Black-Hawk
Species. Species in italics are not Key
45
Semipalmated Plover
Species but may be confused with one or more of the Key Species.
Audio 1
Pale-billed Woodpecker
16
Chestnut-mandibled Toucan
2
Lineated Woodpecker
17
White-collared Manakin
3
Black-cheeked Woodpecker
18
Squirrel Cuckoo
4
White-crowned Parrot
19
Clay-colored Robin
5
Red-lored Parrot
20
Band-backed Wren
6
Mealy Parrot
21
Black-throated Wren
7
Bright-rumped Attila
22
Bay Wren
8
Great Kiskadee
23
Stripe-breasted Wren
9
Social Flycatcher
24
Plain Wren
10
Lesser Greenlet
25
House Wren
11
Blue-black Grassquit
26
White-breasted Wood-Wren
12
Variable Seedeater
27
Nightingale Wren
13
Montezuma Oropendola
28
Song Wren
14
Collared Aracari
29
Slaty-tailed Trogon
15
Keel-billed Toucan
30
Western Slaty-Antshrike
45
Related Documents
Phase 3 - Science Report Final
May 2020 21
Phase 2 Science Report Final
May 2020 26
Phase 1 Science Report Final
May 2020 26
Phase 4 Science Report Final
May 2020 26
Phase 091 Science Report
May 2020 36