Community Assembly and Habitat Specialization of Tropical Tree Species along Moisture Gradients in the Western Ghats Biodiversity Hotspot in India Shivaprakash Kodukothanahally Nagaraju A Thesis In the Department of Biology Presented in Partial Fulfillment of the Requirements For the Degree of Doctor of Philosophy (Biology) at Concordia University Montreal, Quebec, Canada August 2018 © Shivaprakash Kodukothanahally Nagaraju, 2018 CONCORDIA UNIVERSITY School of Graduate Studies This is to certify that the thesis prepared By: Shivaprakash Kodukothanahally Nagaraju Entitled: Community Assembly and Habitat Specialization of Tropical Tree Species along Moisture Gradients in the Western Ghats Biodiversity Hotspot in India and submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY (Biology) complies with the regulations of the University and meets the accepted standards with respect to originality and quality. Signed by the final Examining Committee: ---------------------------------------------------------------------- Chair Dr. Steven Shaw ---------------------------------------------------------------------- External Examiner Dr. N. Parthasarathy ---------------------------------------------------------------------- External to Program Examiner Dr. Laszlo Kalman ---------------------------------------------------------------------- Examiner Dr. Grant Brown ---------------------------------------------------------------------- Examiner Dr. Robert Weladji ---------------------------------------------------------------------- Thesis Supervisor Dr. Selvadurai Dayanandan Approved by ------------------------------------------------------------------------------------------------ Dr. Robert Weladji, Graduate Program Director February 21st, 2019 ---------------------------------------------------------------------------------------- Dr. Andre Roy, Dean, Faculty of Arts and Science ABSTRACT Community Assembly and Habitat Specialization of Tropical Tree Species along Moisture Gradients in the Western Ghats Biodiversity Hotspot in India Shivaprakash Kodukothanahally Nagaraju, Ph.D. Concordia University, 2018 The interactions between ecological and evolutionary processes mediated through functional traits that confer habitat specialization have been proposed to explain the spatial assembly of plant communities both across space and in different habitats. However, the scale at which these mechanisms operate and their relative importance in dominance and assembly of tree communities in different habitat types distributed across spatially-varying environmental gradients in tropical forests have been rarely tested. Here, I elucidate patterns of functional trait and phylogenetic variation and evolutionary history of key functional traits conferring habitat specialization to understand community assembly mechanisms operating within in tropical tree communities distributed across spatially varying environmental gradients and in different habitat types in Western Ghats biodiversity hotspot, India. The chapter 2 focuses on patterns of functional trait and phylogenetic co-variation among a community of tropical canopy trees distributed across spatially varying moisture gradient. I find that tree communities in plots that experience lower precipitation and longer duration of dry period show clustering of both functional traits and phylogenetic relationship suggesting environmental filtering play a key role in the assembly of tree communities in these forests. The chapter 3 explores the relationship between key functional traits, phylogenetic relationship and abundance of 210 co-occurring tree species distributed across contrasting extremes of seasonal flooding gradient i.e. flooded forest and terra-firme forest (non-flooded). I found that repeated evolution of key functional traits together with strong environmental filtering play a key role in determining the ecological success (dominance) and assembly of tree communities in flooded habitat. The chapter 4 focuses on climatic niche evolution and evolutionary history of flooded habitat specialization in global and endemic Myristicaceae members in the Western Ghats. I found that, repeated gain of swamp habitat specialization and associated morphological traits in global and Western Ghats iii Myristicaceae implying seasonal flooding gradient is an important driver of ecological speciation. I also found that local habitat specialization promotes range-wide niche evolution among sister taxa. By elucidating the pattern functional traits and phylogenetic relationship across flooding and spatially varying moisture gradient and analysis of climatic niche evolution and habitat specialization among co-occurring sister taxa, this thesis contributes to our understanding of the determinants of assembly, dominance and diversification of tropical tree communities across diverse habitat types in tropical forest biomes. iv Acknowledgements This thesis is a result of input from several people to whom I am always grateful. First, I would like to thank my supervisor, Dr. Selvadurai Dayanandan, for accepting me into his lab. He offered me invaluable guidance and endless support over the years and encouraged me to perceive my dreams. I have learned many human values from him. I am very fortunate to have such an amazing and kind person as my supervisor. I was also fortunate to have lot of scientific support from my committee member Dr. Jean-Phillipe Lessard, who I should thank and remember not only for providing valuable scientific input to my thesis but also for treating me as his good friend and one of his lab members. I would also like to thank my other committee members, Dr. Robert Weladji and Dr. Grant Brown for providing advice on overall thesis structure and direction. I thank Professor R. Umashaanker who is my master’s supervisor; he has always been a continuous support and inspiration in my scientific career. He generously helped me to structure my present thesis. His love for science motivated many scholars including me to pursue science. He taught me to think creatively and broadly. I am very fortunate to continuously associated with him to work and discuss inspirational ideas. I would like to thank Dr. B.R Ramesh from French Institute, Pondicherry for providing plot wise tree community data to second Chapter of my thesis. I would also like to extend my thanks to Dr. R. Vasudeva from Forestry college, Sirsi who has provided generous support for logistics during my filed work in the Western Ghats and also gave his valuable time to discuss my thesis objectives. I would also like extend my thanks to Dr. Ravikanth from ATREE, Bangalore for providing lab space and consumables for the molecular work. I would like to extend special thanks to Professor Kamal Bawa. I would like to thank my supervisor Dr. Dayanandan for introducing me to Dr. Bawa. He financially supported me from his family fund during my stay in India to write up my thesis. He gave me an opportunity to become a part of his scientific team and introduced me to exciting field of plant reproductive biology. I would like to thank Dr. M.R. Jagadish and Dr. Srikanth Gunaga for their help in the field and unforgettable company. Without their help and support, it would not have been possible for me to complete my thesis project. I also thank Prabhu Biradar, Sharath M. and many other students v from Forestry college, Sirsi for their help during my fieldwork. I would like to thank my field assistants Ganesh Naik and Sandeep Shetty for helping me to lay the plots and collect leaf samples of swampy tree species for DNA analysis. I would also like to thank my lab members at Concordia: Scahin Naik, Mohammed Atif Zayed, and Stephanie Shooner for their generosity, kindness and support. I also thank J.P. Lessard lab members: Kathrene Hebert, Julie Arrowsmith, Vicky, Daniella, Sergio Vega and many others for accepting me as one of their lab members and involving me in weekly group meetings. I thank my Montreal friends: Vinod Parmar, Prina Patel, Neha, Sasmit, Bhoomi, Amit, Sangeeta, Manoj, Anurag, Shreya, Sujith, Chandrika, Pooja, Amool, Rajesh, Divya, Senthil, Ranjan, Soodan, Gayathri and many others, without you people my stay in Montreal would not have been exciting. My very special thanks to Bangalore best buddies: Arvin, Sampath, Charan and Chengappa. You guys were always there with me to celebrate my success and stood with me when I am down. You guys have made my life beautiful and much more exciting. I also equally thank Sandeep Sen, Shweta Basnett, Ramesh BT and Anusha Reddy. Most Importantly, I would like to very specially thank my family for helping me to keep the things in perspective and pursue my dreams. To my parents, thank you for your hard effort in bringing up, respecting my decisions and gave a freedom to listen to my heart and pursue my dreams. To my brothers Raghu and Nagendra, thanks for your prayers and well wishes. To my wife Veena, my heartily thanks for being my best friend and companion, patiently supporting me to complete my thesis. To my brother in-law and mother in-law Manjunath and Geeta, thanks for taking care of my wife and me very well and praying for my success. I thank all my friends in both Montreal and India in case I missed their names. You guys have kept me busy and keep going in my life. This thesis was made possible by funding from the Quebec Center for Biodiversity Science (QCBS), Concordia University, Fonds de Recherche du Québec – Nature et technologies (FRQNT) and the Natural Science and