EFFECTS OF LANDUSE CHANGE AND FOREST FRAGMENTATION ON THE BIODIVERSITY AND ECOSYSTEM FUNCTIONING IN THE TROPICAL LOWLANDS OF SRI LANKA ENOKA PRIYADARSHANI KUDAVIDANAGE B.Sc. (Zoology), M.Sc (Environmental Sciences) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF BIOLOGICAL SCIENCES NATIONAL UNIVERSITY OF SINGAPORE 2011 1 “The forest is a peculiar organism of unlimited kindness and benevolence that makes no demands for its sustenance and extends generously the products of its life activity; it provides protection to all beings, offering shade even to the man who destroys it.” — Gautama Buddha i Dedicated to my parents ii ACKNOWLEDGEMENTS I am grateful to late Prof. Navjot Sodhi, my ex-supervisor whose unique combination of intelligence, determination, intimidation and social skills defined my path into the field of conservation biology. I am indebted, to my supervisor Prof. Edward Webb for persuasion and guidance that enabled me to complete the PhD thesis, and to the constant encouragement provided by Prof. Richard Corlett. I extend my gratitude to Prof Sarath Kotagama, my supervisor in Sri Lanka, and mentor for the last 15 years, for his guidance provided throughout my academic life. I thank all examiners for their most valuable and helpful comments that were adopted in the final version of my thesis. Many thanks to all the past and present staff member and colleagues of the Conservation Ecology, Applied Plant Ecology laboratories and the terrestrial ecology group including Daniel Friess; David Bickford; Mary Rose Posa, Nanthinee Jeevanadam, Reuben Clement, Arvin Diesmos and Lee Wei Kit; the technical and administrative staff including Tommy Tan, Reena Devi Samayanadan, Priscilla Lee, members of the Biodiversity group and the Raffles Museum for Biodiversity research of the Department of Biological Sciences for all the encouragement assistance and inspiration extended in one-way or another. Special thanks towards Janice Lee and Qie Lan, my fellow dung girls for the comradeship of dung beetles. Prof. David J. Lohman (Lohman Lab, City College of New York) is kindly acknowledged for extending a generous helping hand in many challenges faced during my PhD study including correcting manuscripts, assisting analytical problems, helpful discussions and providing resources. I’m grateful to Darren J. Mann, Eleanor Slade and the staff of the Oxford University Museum of Natural History for patiently guiding me through the intense process of species identification and for the opportunity to use the scarab beetle collection at the American Museum iii of Natural History. Thanks to the ScarabNet research team including Finbarr Horgan for sharing with me their knowledge about dung beetles. I acknowledge all my collaborators; Thomas Wanger (Center for Conservation Biology , Stanford University), Neil Collier (Lohman Lab, City College of New York) for analytical work; Priyadarshan Dharmarajan (Ashoka Trust, India), Manori Gunetilleke (National Museums, Sri Lanka) and Deepchandi Lekamge (Sabaragamuwa University) for the taxonomic study. I acknowledge the Department of Wildlife Conservation and the Forest Department, Sri Lanka for granting me access to work in the protected area and permission to export specimen for taxonomic work. I thank the Vice- Chancellor of the Sabaragamuwa University of Sri Lanka and the Department of Natural Resources for kindly facilitating my graduate studies. Gratitude extended to Professors Nimal Gunatilleke, Savithri Gunatilleke and Drs. Eben and Uromi Goodale for expertise knowledge, guidance and helpful discussions. Ravi Amarasinghe, Chamitha de Alwis, Vimukthi Herath, Krishan and Udeni Ariyasiri, Vishan, Amila Perera, Nuwan Hegodaaarachchi, the Wildlife Conservation Society of Galle and the local assistants who supported the field work are acknowledged. The Field research was funded by NAGAO Natural Environmental Foundation, Japan and Joe Grove memorial award, UK, while the taxonomic study was funded by the Oxford University Museum of Natural History, London. The World Bank sponsored IRQUE project and the National University of Singapore Research Scholarship supported the PhD studies. Finally, I thank everybody including my family who stood by me extending their constant support, patience and understanding through the graduate studies. I owe all that I am to my parents, who made it their lifetimes’ goal to help me fulfill my dreams. I remember with heartfelt gratitude and warmth, my father who passed away one month before I entered the graduate iv school of his choice and my mother who stood by me all my life before she passed away seven months ago. She shared my love for nature and all living things, supported my chosen career and enjoyed every one of my field expeditions, participating with great enthusiasm. This thesis is a product of her faith in me. v Contents ACKNOWLEDGEMENTS ......................................................................................................................... iii THESIS SUMMARY ................................................................................................................................... 1 LIST OF FIGURES ...................................................................................................................................... 4 LIST OF TABLES ........................................................................................................................................ 5 APPENDICES .............................................................................................................................................. 6 CHAPTER 1: GENERAL INTRODUCTION ............................................................................................. 7 CHAPTER 2: STUDY SITE ...................................................................................................................... 13 2.1 Sri Lanka and the Lowland Wet Zone: a biodiversity hotspot .......................................................... 13 2.2 From game protection to biodiversity conservation: the history and status of biodiversity conservation in the wet zone of Sri Lanka .............................................................................................. 15 2.3 Study sites: Sinharaja, Kanneliya and Kottawa ................................................................................ 20 2.3.1 Sinharaja Man and Biosphere Reserve ...................................................................................... 20 2.3.2 Kanneliya conservation forest .................................................................................................... 23 2.3.3 Kottawa Kombala conservation forest ....................................................................................... 24 CHAPTER 3: AMPHIBIAN AND BUTTERFLY DIVERSITY ACROSS A LOWLAND TROPICAL LAND-USE GRADIENT IN SRI LANKA ................................................................................................ 28 3.1 Introduction ....................................................................................................................................... 28 3.2 Materials and methods ...................................................................................................................... 29 3.2.1 Study area ................................................................................................................................... 29 vi 3.2.2 Sampling diversity and abundance ............................................................................................ 30 3.2.3 Environmental variables ............................................................................................................ 31 3.2.4 Analysis of species richness and abundance data ...................................................................... 32 3.2.5 Analysis of environmental variables .......................................................................................... 33 3.3 Results ............................................................................................................................................... 34 3.3.1 Butterflies ................................................................................................................................... 34 3.3.2 Amphibians ................................................................................................................................ 35 3.3.3 Environmental determinants ...................................................................................................... 37 3.4 Discussion ......................................................................................................................................... 38 3.4.1 Butterfly response to land-use change ....................................................................................... 38 3.4.2 Amphibian response to land-use change .................................................................................... 40 3.4.3 Environmental predictors of butterfly and amphibian diversity patterns ................................... 42 3.5 Conclusions ....................................................................................................................................... 43 4.1 Introduction ....................................................................................................................................... 51 4.2 Dung beetles (Insecta: Coleoptera: Polyphaga: Scarabaeoidea: Scarabaeidae: Scarabaeinae and Aphodiinae) ............................................................................................................................................