Faculty of Resource Science and Technology

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Faculty of Resource Science and Technology DIETARY, TEMPORAL AND HABITAT RESOURCE PARTITIONING BY FOUR GEKKONID LIZARDS (SAURIA: GEKKONIDAE) AT

1 Faculty of Resource Science and Technology DIETARY, TEMPORAL AND HABITAT RESOURCE PARTITIONING BY FOUR GEKKONID LIZARDS (SAURIA: GEKKONIDAE) AT UNIMAS CAMPUS, KOTA SAMARAHAN, SARAWAK Syazwan Affandi bin Zulkipli Bachelor of Science with Honours (Animal Resource Science and Management) 2013

2 DIETARY, TEMPORAL AND HABITAT RESOURCE PARTITIONING BY FOUR GEKKONID LIZARDS (SAURIA: GEKKONIDAE) AT UNIMAS CAMPUS, KOTA SAMARAHAN, SARAWAK SYAZWAN AFFANDI BIN ZULKIPLI This project is submitted in partial fulfillment of the requirements for the Degree of Bachelor of Science with Honours (Animal Resource Science and Management) Faculty of Resource Science and Technology UNIVERSITI MALAYSIA SARAWAK 2013

3 Acknowledgement Alhamdulillah, I am very grateful to Allah SWT for His willing and blessing, allowing me to complete this project entitled Dietary, Temporal and Habitat Resource Partitioning by Four Gekkonid Lizards (Sauria: Gekkonidae) at Unimas Campus, Kota Samarahan, Sarawak. First of all, I would like to express my deepest thanks and appreciation to my beloved parents, En. Zulkipli b. Md Yusof and Pn. Rahimah bt. Abd. Rahim, my family and all of my friends; for their endless loves, financial support, and encouragement from the beginning till the end. Special thanks to my supervisor: Prof. Dr. Indraneil Das for all his contribution of time and helps; in guiding me, giving me continuous ideas, suggestions and constructive comments on the manuscripts during completion of this thesis. I would also like to express my sincere gratitude to Nur Syarafina Farhah Shukery, Muhammad Hafizan Abd Raoff and Pui Yong Min for their willing helping me during the sampling and computing the data analysis. My thanks also go to all lecturers, staffs and students of Departments of Zoology, who are involved direct or indirectly during this project. Last but not the least, thanks to Department of Zoology, Faculty Resource Science and Technology for giving the opportunity to conduct this project. i

4 DECLARATION I hereby declare that the Final Year Project Report is based on my original work except for quotations and citations, which have been duly acknowledged. No portion of the work in this dissertation has been submitted in support of an application for another degree of qualification of this or any other university or institution of higher learning.... (Syazwan Affandi bin Zulkipli) Department of Animal Resource Science and Management Faculty of Resource Science and Technology Universiti Malaysia Sarawak ii

5 Table of Contents Acknowledgement. I Declaration. II Table of Contents.. List of Abbreviation.. List of Tables List of Figures... III VI VII VIII Abstract Introduction and Objective Background Study Problem Statement Objectives Literature Review Resource Partitioning Geckos Research Methodology Study Sites Field Observation and Techniques Stomach Content Analysis Data Analysis 10 iii

6 3.4.1Dominance of Food Item Niche Breadth Niche Breadth Standardized Niche Overlap Clustering Analysis Results Species Abundance Microhabitat Diets Diel Time (Temporal) Dominance of Food Item Niche Breadth Microhabitat Diet Diel Time (Temporal) Overlaps Microhabitat Diet Diel Time (Temporal) Discussion Observation Stomach Content Analysis 25 iv

7 5.3 Microhabitat Diet Diel Time Niche Breadth and Overlap Clustering Analysis Conclusion and Recommendation.. 32 References 33 APPENDIX 1 Data Sampling APPENDIX 2 Stomach Content Data.. 36 v

8 List of Abbreviation g Geh. mutilate Gek. monarchus Gram Gehyra mutilata Gekko monarchus H. platyurus Hemidactylus platyurus H. frenatus Hemidactylus frenatus m mm MSVP SVL Meter Millimeter Multi-Variate Statistical Package Snout Vent Length vi

9 List of Tables Table 1 Relative Frequency of Samples Table 2 Frequency Occurrences of The Species At Specific Habitat Table 3 Summary of Stomach Content Table 4 Frequency Occurrence of Each Species at Specific Period of Time Table 5 Percentage of Dominance Food Item by Each Species Table 6 Niche Breadth in Microhabitat Table 7 Niche Breadth in Diet Table 8 Niche Breadth in Diel Time (Temporal) Table 9 Overlap in the Microhabitat Table 10 Overlap in Diet Table 11 Overlap in Diel Time (Temporal) Table 12 Data recorded during sampling Table 13 Data recorded during stomach content analysis vii

10 List of Figures Figure 1 Frequency occurrences of each species in UNIMAS campus Figure 2 Gekko monarchus Figure 3 Hemidactylus frenatus Figure 4 Hemidactylus platyurus Figure 5 Gehyra mutilata Figure 6 Percentage of particular species at specific microhabitat Figure 7 Percentage of microhabitat partitioning for four sympatric geckos species Figure 8 Percentage of each prey in geckos stomach Figure 9 Percentage of gecko species at specific time period Figure 10 Dendogram of relation between each species in microhabitat Figure 11 Dendogram of relation between each species in diets Figure 12 Dendogram of relation between each species in diel time viii

11 Dietary, Temporal and Habitat Resource Partitioning by Four Gekkonid Lizards (Sauria: Gekkonidae) at UNIMAS Campus, Kota Samarahan, Sarawak Syazwan Affandi bin Zulkipli Animal Resource and Management Programme Faculty of Science and Technology Universiti Malaysia Sarawak ABSTRACT A study of resource partitioning among four sympatric geckos species were conducted at UNIMAS campus over a period of three days. Four species were collected- Hemidactylus platyurus, Hemidactylus frenatus, Gehyra mutilata and Gekko monarchus. A total 46 specimens were collected to compare resource use in terms of diet, microhabitat and use of diel temporal resources. Berger-Parker Diversity Index, Diversity Index of Simpson (1949) and Mac Arthur and Levi s (1967) were used to compute food dominance, niche breadth and niche overlap. Results show partitioning only for microhabitat and diel time, but not in dietary resources. Keywords: gecko, resource partitioning, diet, microhabitat,diel time, overlap. ABSTRAK Kajian mengenai pembahagian sumber dalam kalangan empat simpatrik spesis telah dijalankan di kampus UNIMAS sepanjang tiga hari. Empat jenis spesis telah dikumpul dan dibandingkan, iaitu Hemidactylus platyurus, Hemidactylus frenatus, Gehyra mutilata dan Gekko monarchus. Sejumlah 46 ekor sampel telah ditangkap untuk membandingkan pembahagian sumber dalam mikrohabitat, masa makan dan diet. Berger-Parker Diversity Index, Diversity Index of Simpson (1949) dan Mac Arthur and Levi s (1967) telah diguna pakai untuk menganalisa dominasi makanan, keluasan niche dan pertindihan niche. Keputusan menunjukkan pembahagian sumber hanya berlaku di mikro-habitat, masa pemakanan tetapi tidak pada sumber makanan. Kata kunci: gecko, pembahagian sumber, diet, microhabitat, masa makan, pertindihan. 1

12 CHAPTER 1 INTRODUCTION 1.1 Background Study Whether species can coexist in the same animal assemblage is determined by physical and biological factors, the concept referred to as resource partitioning, first introduced in the mid-1960s (Schoener, 1965) to refer to ways species differ in their use of resources. Resource partitioning patterns may generally derive from the interaction of some categories of causes, including predation, extrinsic and intrinsic constraints on an organism s performance, and interspecific competition (Toft, 1985). Thus, the main scopes of resource partitioning studies are not only to describe the patterns as they occur in living communities, but also to understand factors causing these patterns (Schoener, 1977). In this project, I studied diet, habitat and temporal resource partitioning in geckos including how sympatric species choose food, habitat and time of activity to reduce competition. Ecological differences in the use of trophic (food), spatial (place) and temporal (time) resources have long been associated with the structure of biological community because of their potential to reduce competition, thereby apparently facilitating coexistence (Pianka, 1975). The ways species within a communities partition the available resources is a determinant of the diversity of coexisting species (Pianka, 1974). The ability to share the resources, which lead to greater niche overlap, will support more species rather than one with lower niche overlap. An understanding of the level of resource overlap 2

13 between the existence species will enhance the knowledge on interactions between these species. In order to understand the competition and determinant of the species diversity, this study will focus on the ecological requirement of each species within the study site. The major purpose of resource partitioning studies is to analyze the limits of interspecific competition and to determine the number of species that can coexist (Schoener, 1974). A total of 108 species of lizards are known from Borneo, of which 29 represent the family Gekkonidae, and 11 of these are endemic to the island (Das, 2004). Geckos are not only present in forested areas, but are also able to survive within urban areas. A few species are found on walls of buildings or on wooden houses. Representative of this group on Borneo are Gehyra mutilata, Gekko monarchus, Gekko gecko, Hemidactylus brookii, Hemidactylus frenatus, Hemidactylus garnoti, Hemidactylus platyurus and Lepidodactylus lugubris (Das, 2010). Most of the world s geckos are nocturnal rather than diurnal, and on Borneo, all 29 known species are nocturnal in habits. 1.2 Problem Statement Lizards are enormously diverse and differ in their morphology, physiology and life history. Studies on geckos as models allow an understanding of their diet, habitat and time resource partitioning. In this project, I report variation in food intake, examine habitat specialization and use of time by different species of geckos. I studied their stomach contents to see if there are any variations in food types, observe their habitat and time of activity during the sampling period, based on their location found and the light intensity of the location. 3

14 The extent of spatial overlap between sympatric species largely determines the potential for competition for all resources. Dietary overlap can also lead to interspecific competition. There are no documented information on dietary resource partitioning between sympatric gecko species in Sarawak or indeed, anywhere in Borneo. Recent studies have forced a reassessment of this perception, because it is increasingly clear that some reptiles exhibit complex social behaviour and niche partitioning (Kearney et al. 2001). 1.3 Objectives The objectives of this research are, to determine whether different sympatric species of geckos: a) consume different food resources, b) utilize different microhabitats and c) are active at different time 4

15 CHAPTER 2 LITERATURE REVIEW 2.1 Resource partitioning Concepts of resource partitioning, as originally developed, relates to evolutionary change in species in response to selection pressure generated by interspecific competition (Walter, 1990). The term earliest use has been attributed to Schoener (Toft, 1985) and MacArthur (1985), Hutchinson (1959), (Walter, 1990). Schoener (1965) stated that a first stage in the evolution of the sympatric species association is often food partitioning by size or dimensional properties of the immediate food environment. He also stated that "The extent to which resource-partitioning patterns in fact result from pressures, evolutionary or otherwise, to avoid interspecific competition is now more of an issue than when most of the studies were carried out" (Schoener, 1986). Resource partitioning among competing species is one of the most important phenomenon in population biology (Roughgarden, 1976). Numerous studies have documented the limitation of the distribution and abundance of reptile species by competitively dominant reptiles. Compilations on how resources are partitioned among community members that belong to particular taxonomic groups have been done. For example, Toft (1985) has summarized the available information on amphibians and reptiles, and Ross (1986) has reviewed the same for fishes. 5

16 Investigations of resource overlap and interactions between species may provide insight into the mechanisms of sympatry that are operating. These mechanisms act to decrease either exploitative competition, by resource partitioning (Schoener 1974), or interference competition, by avoidance (Case and Gilpin 1974), to facilitate coexistence with a dominant or predatory species. Habitat, food and time are the three main resources, believed to be partitioned by competing species (Pianka, 1975). Animals partition environmental resources in three basic ways: temporally, spatially, and tropically; that is, species differ in times of activity, the places they exploit, and/or the food they eat. Such differences in activities separate niches, reduce competition, and presumably allow the coexistence of a variety of species (Pianka, 1973). Schoener (1974) divided available resources into six categories, which are microhabitat, food type, food size, diel time and seasonal time. Analysis of foraging biology has been an important subject in ecology and evolutionary biology (Perry and Pianka, 1997). Members of the Gekkonidae tend to show a complex trend of foraging which are intermediate, alternating or fluctuating foraging mode which making them poor understood (Perry and Pianka, 1997). The mode of foraging or the way in which a lizard uses space can influence both its place and food niches, which widely foraging species typically have broader place niches than sit-and-wait species and a pairs of lizard species with high overlap along one niche dimension may have low overlap along another niche dimension to reduce interspecific competition between them (Pianka, 1973). 6

17 2.2 Geckos Chou (1975), reported five gecko species associated with houses in Singapore- Gehyra mutilata, Gekko gecko, Gekko monarchus, Hemidactylus frenatus and Hemidactylus platyurus, of which the most abundant species was Hemidactylus frenatus. Most geckos are nocturnal hunters that feed on insects, spiders and other small invertebrates. The Tokay gecko, Gekko gecko is a large species whose diet includes heftier prey items, such as small lizards, birds and mammals. Day geckos from the islands of the Indian Ocean (Phelsuma sp.) feed on insects, but also bolster their diet with pollen, fruit and flower nectar. Geckos locate on their food using a combination of sight and smell.pianka (1973), stated that being active at different time leads to use of different resources, such as prey species, temporal separation of activities, which will decrease the competition between lizard species and the most conspicuous temporal separation of activities is the dichotomy of diurnal and nocturnal lizards, which are entirely non-overlapping in temporal dimension. Some lizards are strongly restricted to their respective habitats, and various species have specialized their microhabitats requirement.most lizards are insectivorous and fairly opportunistic feeders, taking without any obvious preference, whatever arthropods they encounter within a broad range of types and sizes. Smaller species or individuals, however, do tend to eat smaller prey than larger species or individuals also; differences in foraging techniques and place and time niches often result in exposure to a different spectrum of prey species. Few lizard species have evolved severe dietary restrictions but some of them also depend on the abundance of the food sources (Pianka, 1973). 7

18 CHAPTER 3 RESEARCH METHODOLOGY 3.1 Study Sites Field work was conducted within an urbanized area in the Universiti Malaysia Sarawak (UNIMAS) campus, which is located in Kota Samarahan District of Sarawak State, Malaysia (on Borneo). The targeted sampling sites were buildings and isolated patches of trees. The original vegetation is mostly peat swamp forests. 3.2 Field Observation and Techniques Geckos were collected during their natural period of nocturnal activities, which begin after sunset and extended at least until midnight. The periods of times were designated into four different parts, which are a) 19:30 20:30 h, b) 20:31 21:30 h, c) 21:31 22:30 h and 22:31 23:30 h. Most geckos are nocturnal rather than diurnal and at this locality, all are nocturnal. The geckos were located by observing using light sources nearby or headlamp within the dark area. All specimens were caught by using one of the several methods, primarily by attracting them with a laser pointer and catching them when accessible. Beams from laser pointers attract gekkonid lizards to the projected light, which possibly is mistaken for food or perhaps a potential competitor. From their usually high perches, gekkonid lizards were lured toward my assistant. This technique worked well on walls of buildings as well as tree trunks, and it is more successful in the early evening than later, 8

19 presumably when geckos are becoming active and are hungry. Using rubber band is more effective when the geckos are no longer hungry. Most individuals were grabbed by the head between the thumb and forefinger before insertion into containers and labeled with the field collection numbers. Founding of the geckos provide enough data on their ecology, such as the foraging behaviour, microhabitat and the time of activity. The following data were recorded during the sampling session: 1) Species identified using external morphological features following Das (2004). 2) Time encounter time (0000 hours) for each gecko. 3) Height the vertical distance (in meters) from the substrate to where a gecko was first observed. 4) The microhabitat-dark, shade or light. Some species were quite common, such as Hemidactylus platyurus and Gehyra mutilata whereas others were difficult to acquire in large numbers either because of restricted habitat requirement or an apparent rarity. Specimen identification was done by Prof. Dr. Indraneil Das and followed by referencing to the series of voucher specimens to confirm the identities. The snout-vent lengths were measured to identify their maturity. Specimens were measured using a ruler (to the nearest mm) and weighed with an electronic-weight balance (to the nearest gm). 3.3 Stomach Content Analysis Preserved specimens were dissected for stomach contents observation, in order to compare diets between species. They were subsequently preserved in the ethanol before long-term storage in formalin. All stomach contents were preserved in ethanol and 9

20 observed under an Olympux SZX9 microscope for identifications of food items recovered. I used the work of Bland (1978), How to Know the Insects, for identification of stomach contents. Prey in the stomachs were counted individually and recorded in the data sheet. There are six successful type of prey identified, which are Hymenoptera, Ants, Diptera, Isoptera, Spider and Indeterminate for the unrecognized stomach content. Ants were separated from order Hymenoptera due to the abundance of hymenoptera in stomach contents. 3.4 Data Analysis Data analysis formulae adopted from other studies on resource partitioning and method of measuring the overlap and niche breadth (Hulbert, 1978; Pianka, 1974; Das, 1996) Dominance of Food Items To examine the degree of dominance food items in stomach samples, the Berger-Parker Diversity Index was used: Equation 1 d=, Where N is the total number of individuals and, the number of individuals in the most abundant resource type Niche Breadth To quantify the variety of resources exploited by different species (niche breadth), the diversity index of Simpson (1949), were used: 10

21 Equation 2, Where is the proportion of the th resource category used Standardized Niche Breadth Standardized of niche breadth (B) of each species express it on a scale 0 to 1.0 using Hurbert s (1978) standardized niche breadth formula: Equation 3 Where B is niche breadth and N is the total number of spatial type for the species of interest. 11

22 4.3.4 Niche Overlap Niche overlap between the species will be calculated by using a symmetric version of Mac Arthur and Levin s (1967) equation: Equation 4 Ojk=Okj= Where Pi and Pik are the proportions of the resource used by the and the species, respectively. It cannot generate values less than zero or greater than one. Dietary analyses are based on ordinal level of prey identification. Computations of niche breadths, niche overlaps and dominance were made from data after compilation into a rectangular m by n matrix that indicates the rate of utilization of each m discrete resource type (food, time or microhabitat) by n gecko s species Cluster analysis Cluster analysis was performed using Multi-Variate Statistical Package Version 3.13, MSVP (Kovach, 2002). The agglomerative hierarchical clustering method was conducted to generate dendrogram, utilising unweighted pair-group method using arithmetic averages approach. The programme also was set to generate the similarity matrix of the calculation. All figures in the following steps are referred in Appendix 3. i. MSVP programme for Windows was launched. The file contains cluster data was loaded and a window shows an open file with total variables and samples or cases appeared. 12

23 ii. iii. ii. In the analyses menu, cluster analysis was selected. iii. Cluster analysis options pop-up window appeared, and from the dropdown list of clustering method, UPGMA was selected. For similarity or distance, I selected the interest index from the dropdown list, e.g., Euclidean. I clicked OK to continue iv. iv. Next, the output data results were generated in two windows- MSVP Results and Graphs. The output was saved as text and JPEG files. 13

24 Number of Individuals CHAPTER 4 RESULTS 4.1 Species Abundance Hemidactylus platyurus showed the highest number of individuals collected during the sampling, followed by Gehyra mutilata. Based on the observation along the sample collection, Hemidactylus platyurus is the most sighted individuals and easier to catch, while Gekko monarchus are the rarest species and hardest to find. Table 1: Relative Frequencies of Samples SPECIES Total Weight(Mean)(g) SVL (Mean) (mm) H. platyurus H. frenatus Geh. mutilata Gek. monarchus Total Species Collected in UNIMAS campus 35% 32.61% 30% 25% 21.74% 23.91% 21.74% 20% 15% 10% 5% 0% H. platyurus H. frenatus Geh.mutilata Gek. monarchus Species Figure 1: Frequency occurrences of each species in UNIMAS campus. 14

NOTES ON THE ECOLOGY AND NATURAL HISTORY OF CTENOPHORUS CAUDICINCTUS (AGAMIDAE) IN WESTERN AUSTRALIA

NOTES ON THE ECOLOGY AND NATURAL HISTORY OF CTENOPHORUS CAUDICINCTUS (AGAMIDAE) IN WESTERN AUSTRALIA By ERIC R. PIANKA Integrative Biology University of Texas at Austin Austin, Texas 78712 USA Email: erp@austin.utexas.edu