The Influence of Environmental Factors and Landcover Change on the Distribution and Metacommunity Structure of Upper Montane (Shola) Forests in the Western Ghats Thesis Submitted for the Degree of Doctor of Philosophy Thesis Submitted By Arundhati Das Reg No: 090900049 Thesis Submitted to Manipal University Manipal, 576104 Research carried out at The Academy for Conservation Science and Sustainability Studies Ashoka Trust for Research in Ecology and the Environment (ATREE) Bangalore Certificate This is to certify that the thesis entitled “The influence of environmental factors and landcover change on the distribution and metacommunity structure of upper montane (shola) forests in the Western Ghats” submitted by Ms. Arundhati Das, for the award of Doctor of Philosophy for, Manipal University, Manipal, is a record of the research work carried out by her during the period of her study in this university under my guidance and supervision and the thesis has not formed the basis for the award of any degree, diploma or other similar titles. Signed by Guide with name and date Place: Bangalore Date: April 14, 2015 i Declaration by the candidate I Arundhati Das, hereby declare that this thesis “The Influence of Environmental Factors and Landcover Change on the Distribution and Metacommunity Structure of Upper Montane (Shola) Forests in the Western Ghats” has been compiled by me under the supervision of Dr. Kamaljit Singh Bawa, President, Ashoka Trust for Research in Ecology and the Environment (ATREE), Bangalore. This thesis has not been previously submitted for the award of any degree, diploma, associateship, fellowship or its equivalent to any other university or institution. Place: Bangalore ----------------------------- Date: 14/4/2015 (Arundhati Das) ii Acknowledgements This thesis describes the study of a community of montane forest trees, but in the end it is the vast and wonderful community of people that have inspired, supported and contributed to this work that really matters. I would like to start by thanking my parents, without whose unflinching support – moral, emotional and financial - I would not have been able to complete this endeavour and emerge at the end (more or less) sane. I would like to acknowledge the patient support, wise guidance and intellectual inputs of my Guide Dr. Kamaljit Singh Bawa and my co-Guide Dr. T. Ganesh. I am very grateful to Dr. Harini Nagendra whose valuable inputs, advice and suggestions have strengthened the work, making it richer and more cohesive. She has been a wonderful person to work with and have on my committee. Dr. Robert John Chandran contributed greatly to various aspects of the study, including data gathering, soil sampling and analysis (in the labs at IISER, Kolkatta) and the writing of the fourth chapter. I am thankful for his active interest in the work and critical inputs. Stipend support during my tenure as a PhD student was provided by the JRS Foundation, ATREE-Noragric Grant, which also supported some of my field work, and the Tata Social Welfare Trust. I also received support from the Canadian Commonwealth Scholarship. The two and a half years spent in the Nilgiris gathering data and exploring sholas will forever remain one of the most valuable, memorable and worthwhile experiences of my life. I worked in remote locations that posed several logistic challenges and was successful only because of the generous support of several people. I would like to begin by thanking Tamil Nadu State Forest Department and the field staff of Mukurthi National Park and the South Division of Nilgiris Reserve Forest. In particular, I would like to acknowledge the support of the Chief Wildlife Warden and Field Director for Mukurthi N.P. as well as the Divisional Forest Officer for Nilgiris South Division. I am extremely grateful to Dr. Kartik Shanker and Dr. Raman Sukumar at the Centre for Ecological Sciences, Indian Institute of Science, for allowing me to use their field station in Upper Bhavani. Without this, much of the sampling within parts of Mukurthi N. P. and the surrounding areas would have been impossible. My hard-working and able field assistants were: Paul Dorai, V. Rathish, Thorthai, Mayavan, Kishore and James. I owe them a lot for the long hours spent in sholas, often in difficult conditions, racing against time or the weather to complete a vegetation plot. Their good company, field knowledge and dedication were much appreciated, as was Paul’s cooking! The field staff of T.N. Electricity Board Settlement in Upper Bhavani welcomed us - I am very thankful for their help with logistics, field station maintenance and for including me in all of their festivals. I thank Devcharan Jathanna for his time and assistance with field work. Initial field reconnaissance and setting up was greatly assisted by Dr. Siddhartha Krishnan at ATREE and his wide network of acquaintances in the Nilgiris. In particular, I would like to acknowledge Mr. Renia, Farooq and Satish. I am very grateful to the owners and management of several estates for allowing me to sample sholas and providing accommodation and field assistance: Korakundah Tea Estate, Thia Shola Tea Estate, Royal Valley Estate and Prospect Tea Estate. I would especially like to thank Mr. iii Preetham Dambekodi, Manager of Korakudah Estate and Mr. Siddharth Shankar, Assistant Manager of Korakundah Estate for their tremendous support, encouragement and assistance. My friends, colleagues and peers at ATREE, Bangalore were a tremendous source of support and encouragement. I am very grateful to all ATREE Fellows (past and present) who have spent incredible amounts of their valuable time and effort to build a unique and remarkable PhD programme from scratch in less than a decade! I am one of many students who have benefitted greatly from their dedication to such institution building. I would like to thank the Academic Council, especially Academy Conveners, Dr. Aravind Madhyasthya and Dr. Nitin Rai. I would also like to thank Dr. Gladwin Joseph, former Director, ATREE for always supporting my efforts and strongly encouraging me to pursue a PhD. I am also grateful to Dr. Ganesan Balachander, Director, ATREE, for his support of the PhD programme and for always making time to listen and respond to student concerns. My deepest gratitude to the following ATREE administrative and support staff: Ms. Madhavi, Mr. Ramesh, Mr. Obaiah (librarian extraordinaire!), Mr. Gopi, Ms. Sindhu, Mr. Saji, Ms. Hemalatha. Ms. Meetu Desai and of course, Raghu! I am very grateful to Dr. Jayashree Ratnam and Dr. Mahesh Sankaran at the National Centre for Biological Sciences for their advice on soil sampling and analysis and for use of their lab facilities to conduct soil analysis. Chengappa and Nandita were both very helpful in conducting the ICP analysis on soil. Rutuja Dhamale provided assistance with texture and LECO analysis. I would like to thank Samira Agnihotri for help with Matlab analysis. I have learned a great deal from many discussions with others working in the shola-grassland system of the Western Ghats. Particularly, Dr. Robin Vijayan, Dr. Milind Bunyan, Atul Joshi, Bob Stewart, Tanya Balcar and Suprabha Seshan. I thank Devcharan Jathanna, Dr. Bharath Sundaram, Dr. Kartik Shanker, Dr. Ankila Hiremath, Dr. R. Ganesan and Dr. Giby Kuriakose for valuable discussions and inputs on the data and analysis. I benefitted greatly from a six month visit to Dr. Madhur Anand’s lab at the University of Guelph, supported by the Canadian Commonwealth Scholarship. I thank her as well as Dr. Wasim Ashiq, Alice Cecile, Dr. Mark Leithead, Dr. Paul Caplat, Dr. Valerio de Patta Pillar, Dr. Carolina Blanco for many useful discussions on vegetation ecology and inputs on analysis. While there, I attended a summer school organized by the Forest Complexity Modelling Group, which was extremely useful and introduced me to some of the analytical techniques that I have used in this study. Finally, I wish to express my deep gratitude for the formative role that two people have played in my intellectual and academic development. Dr. Dean Urban, my graduate advisor, instilled in me an abiding interest in landscape ecology and its application to forest ecosystems, and taught me to think and write more clearly – guidance I benefit from to this day! The other person was my aunt Mandira Banerji, who was my biggest supporter in this endeavour, cheering me on until the bitter end. She instilled in me a love of learning and taught me the importance of language and of clear, proper communication. She is sorely missed. My biggest regret is that I did not complete this in time for her to read it. iv Executive Summary Tropical montane cloud forests are unique habitats with great ecological and hydrological significance. In the Western Ghats, these upper montane forests (also known as sholas) and associated grassland habitats form approximately 1% of the land area but harbour disproportionately high numbers of endemic taxa. Despite their great conservation significance, little is known about how patterns of tree and shrub species composition vary across space, how environmental factors such as soil, climate and topography affect tree and shrub community composition, and how widespread conversion of surrounding grasslands to tea and exotic tree plantations has affected shola forest communities. The naturally fragmented nature of shola communities, which display patchiness at hierarchically nested scales, also makes them an ideal system in which to study metacommunity structure as species distributions, interactions and ecological processes, within and across fragments are likely to have equilibrated over many hundreds of generations (for trees). Hence the central underlying assumption of the species sorting perspective of the metacommunity framework, (i.e. that local community dynamics are at equilibrium) is more likely to be met in such a system. Further, recent conversion of the natural grassland matrix to exotic tree plantations and tea estates, is likely to have disrupted this equilibrium in complex and unpredictable ways, which can provide greater insights into mechanisms driving metacommunities dynamics in general and effects of landscape matrix conversion on plant communities in particular.