Extended Abstract Of Thesis

Comparative Study of Lizard Population between Mahogany Plantation and Secondary Old Growth Forest at Mt. Makiling Forest Reserve

An Extended Abstract Presented to the Department of Biological Sciences College of Science University of Santo Tomas

by Fabunan, Melody Aivi B. Gerardo, Mary Antonette O. Maguslog, Justine P. Salumbre, Renz L. Surquia, Joseph Michael S. 4BIO6

Mrs. Mae Lowe Diesmos Thesis Adviser

INTRODUCTION

Biodiversity is the sum of all the different species of animals, plants, fungi, and microbial organisms living on Earth and the variety of habitats in which they live. It underlies everything from food production to medical research. Scientists have discovered and named only 1.75 million species—less than 20 percent of those estimated to exist. Much of the Earth’s great biodiversity is rapidly disappearing. Species of plants, animals, fungi, and microscopic organisms such as bacteria are being lost at alarming rates. The increasing awareness regarding the increase of species extinction has led to the practice of conservation biology through the principles of biodiversity. Habitat loss and degradation may be the largest single factor in reptile loss. (Brown et al., 2000) Further researches in the fields of Biodiversity and Conservation Biology may just pave the way for further awareness of the current status of animals, in general, and of lizards, in particular. It is then the objective of this study to generate an honest evaluation of lizard population and lizard diversity status between Mahogany Plantation, a fragmented habitat and Secondary Old-Growth Forest in Mt. Makiling for further appreciation of the environment and to at least provide a credible view of the lizard population with respect to biodiversity and habitat fragmentation. This study dealt with the assessment of lizards found in Mahogany plantation and Secondary Old Growth forest of Mt. Makiling using species density and population count. The study was limited to lizard population in Mahogany Plantation and Secondary Old-Growth Forest of Mt. Makiling from June-November 2008 only.

METHODOLOGY Data was gathered from June-November 2008 with a total of 7 sampling trips using random strip transect distance sampling measuring 50m x 10m each. The species collected on both sites were captured, placed in Ziplocs, and documented using digital camera. Species were identified using field guidebooks, consultation with expert Herpetologist and interview of local residents. The data were tabulated, graphed and analyzed using statistical tests namely: Species Effort Curve, MannWhitney U test for two independent sample, Simpson index of diversity and Sorensen Quantitative index. (See Fig.1 for Schematic Diagram of Methodology)

RESULTS AND DISCUSSION A total of 12 species of lizards were found in both Mahogany plantation and Secondary Old Growth Forest. (See Table 1) The total number of species count in the mahogany plantation is 26 while in the secondary old growth forest yielded a total count of 39. Using MannWhitney U test for two independent samples with a p-value of 31, which is greater than the critical value of 14 at a confidence interval of 0.05, thus statistically indicating the difference between the two sampling sites. Habitat fragmentation directly affects lizard population. This can be corroborated by the number of species observed in secondary old growth forest, a less fragmented habitat as opposed to Mahogany Plantation. The most diverse of both sites is the Secondary Old Growth since there are 9 identified species present compared to the Mahogany Plantation having only 5 species present with Eutropis multicarinata as the most frequent species in both sites, and, Lipinia vittigera in the Secondary Old Growth. On the other hand, Varanus salvator, Gonocephalus sp., Sphenomorpus steerei and the 2 unidentified species are the least frequent species. (See Fig.2) In the two study sites, the group has found out that the most frequent species namely: Sphenomorphus cumingi, Lipinia pulchella and Eutropis multicarinata belong to the same family of Scincidae. Skinks, as they are commonly known, are the most diverse group of lizards. They are found in various habitats and are more arboreal and terrestrial than aerial or aquatic, which are catered by the environment of the sampling sites contributing to their abundance than the other family of lizards. Similarities between the two sampling sites were also computed using Sorensen quantitative index. This index has a value of 0 when samples have no species in common at all, while high value indicates low diversity. (Magurran, 2006) The computed value for Sorensen is 0.95, indicating high diversity in the sampling sites and little commonalities between the two further corroborating the result from Mann-Whitney U Test for two independent sample stating that there is a significant difference between the two sites. Using the Simpson index of diversity, the difference between the two sampling sites in terms of diversity, was computed. This index states that the

higher the value, the stronger the dominance but lower in diversity. (Odum, 2005) The computed values were DMahogany of 0.21 and DSecondary of 0.14, thus, Secondary Old-Growth forest, a natural habitat, is more diverse than the Mahogany Plantation.

CONCLUSION This study has focused on the following: a) the diversity of lizard population in a fragmented and natural habitat; and b) the effect of fragmented habitat in lizard population diversity. The group employed random strip transect distance sampling since it is the most convenient because it facilitates easy counting of species and, due to the study sites vast area, strip transects can be expediently performed. A total of 12 species were observed in both mahogany plantation and secondary old growth. Before diversity can be established, a Mann-Whitney U Test was performed to detect whether a significant difference exists between the two habitats. The result yielded that mahogany plantation and secondary old growth differs in terms of species diversity. Having established the difference, the Simpson’s index was used to evaluate the degree of biodiversity with the conclusive result that lizards in the secondary old growth is much more diverse compared to that of mahogany plantation. A Sorensen quantitative index was also computed. The result was that there is minimal lizard species similarity between the two habitats.

REFERENCES: Brown, R. M., J. A. McGuire, J. W. Ferner, N. Icarangal, Jr. & R. S. Kennedy. 2000. Amphibians and reptiles of Luzon island, II : Preliminary report on the herpetofauna of Aurora Memorial National Park, Philippines. Hamadryad Vol. 25 No. 2. Diesmos, A. C., R. M. Brown, A. C. Alcala, R. V. Sison, L. E. Afuang, G.V. A. Gee. 2002. Philippine amphibians and reptiles : An overview of species diversity, biogeography, and conservation. UP Center for Integrative & Developmental Studies Chronicles. Magurran, A.E. 2004. Measuring biological diversity. Blackwell Science Ltd. : India. Mendenhall, W., R. J. Beaver, B. M. Beaver. 2006. Introduction to probability and statistics. Brooks/Cole : Singapore.

Mt Makiling Forest Reserve

Mahogany Plantation

Secondary Old-Growth Forest

Data gathering (strip-transect distance sampling)

Photograph Documentation

Graphical Analysis - sampling effort curve

Statistical Analysis -Mann-Whitney U test -Simpson index of diversity - Sorensen index

Fig.1: A schematic diagram of the Methodology

Table 1: Species account of Lizards in Mahogany Plantation and Secondary Old-Growth Forest

Species Family Agamidae Genus Draco Draco spilopterus Genus Gonocephalus Gonocephalus semperi Family Gekkonidae Genus Gekko Gekko gecko Family Scincidae Genus Brachymeles Brachymeles bonitae Genus Dasia Dasia grisea Genus Eutropis Eutropis multifasciata Eutropis multicarinata Genus Lipinia Lipinia vittigera Genus Sphenomorphus Sphenomorphus jagori Sphenomorphus cumingi Sphenomorphus steerei Family Varanidae Genus Varanus Varanus salvator Total

Mahogany Plantation

Secondary Old Growth Forest X X

X X X X

X X

X

X

X

X X X

5

X 10

10 9 8 7 6 5 Count

4 3 2 1 0

S. jagori G. gecko D. grisea S. steerei B. bonitae G.semperi V. salvator S. cumingi L. pulchella D. spilopterus E. multifasciata E. multicarinata Lizards Fig.2: Frequency of lizards in Mahogany Plantation and Secondary Old-Growth Forest