ADAPTATIONS TO HETEROGENOUS HABITATS: LIFE-HISTORY CHARACTERS OF TREES AND SHRUBS By AMY ELISE ZANNE A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2003 To my mother, Linda Stephenson, who has always supported and encouraged me from near and afar and to the rest of my family members, especially my brother, Ben Stephenson, who wanted me to keep this short. ACKNOWLEDGMENTS I would like to thank my advisor, Colin Chapman, for his continued support and enthusiasm throughout my years as a graduate student. He was willing to follow me along the many permutations of potential research projects that quickly became more and more botanical in nature. His generosity has helped me to finish my project and keep my sanity. I would also like to thank my committee members, Walter Judd, Kaoru Kitajima, Jack Putz, and Colette St. Mary. Each has contributed greatly to my project development, research design, and dissertation write-up, both in and outside of their areas of expertise. I would especially like to thank Kaoru Kitajima for choosing to come to University of Florida precisely as I was developing my dissertation ideas. Without her presence and support, this dissertation would be a very different one. I would like to thank Ugandan field assistants and friends, Tinkasiimire Astone, Kaija Chris, Irumba Peter, and Florence Akiiki. Their friendship and knowledge carried me through many a day. Patrick Chiyo, Scot Duncan, John Paul, and Sarah Schaack greatly assisted me in species identifications and project setup. A number of willing undergraduates agreed to toil through my many seed and seedling lab measurements including Carolyn Cross, Robyn Gartner, Jessi Patti, Laura Stockman, and Gabe Wagman. I thank them for their patience and diligence. I received help with soil analyses from Jacob Aniku, Nick Comerford, Hugh Popenoe, Larry Schwandes, and Ted Schuur. Both Nick Comerford and Larry Schwandes graciously opened their labs for me to conduct my analyses. Ben Bolker, Kavita Isvaran, Michael Palmer, Suhel Quader, and Nat Seavy provided assistance with statistical analyses. I would especially like to thank Ben Bolker, as I would have been unable to conduct many of the analyses without his iii guidance. I also thank Nat Seavy who was always on the lookout for new ways to analyze my data. Kavita Isvaran, Rebecca Kimball, Suhel Quader, and Doug Soltis assisted me with phylogenetic analyses. I would like to thank the staff of the Department of Zoology and Botany for their assistance throughout my graduate career. I would like to thank my family, especially my mother. They were supportive and encouraging whether or not they knew what I spent all those years doing. I would also like to thank Patrick Chiyo for being such a wonderful companion whether it was exploring the remote wilds of his home in Uganda or the remote wilds of my home in New Hampshire, especially in the winter with no heat. Many thanks are extended to friends in Gainesville. They have been both warm friends and academically-stimulating colleagues. I would like to thank the members of AAPIGS as our meetings led to many important discussions and insights. I extend special thanks to my officemates, Kavita Isvaran and Suhel Quader, who have appeared in many of the categories throughout this list. They were kind enough to open both their home and their office to me (especially toward the end of my dissertation, when their help was most needed). I would also like to thank Sarah Bouchard and Laura Sirot, who entered the graduate program with me and Scot Duncan and Denise Trunk, who were already here when I arrived. They have been strong supports for many years. This research was supported in part by College of Liberal Arts and Sciences Grinter and Dissertation Fellowships and a Ford Foundation Grant. I would also like to thank the Uganda Wildlife Authority, Makerere University, and Government of Uganda for allowing me to conduct my research in Kibale National Park. iv TABLE OF CONTENTS page ACKNOWLEDGMENTS....................................................................................................iii LIST OF TABLES.............................................................................................................vii LIST OF FIGURES........................................................................................................... ix ABSTRACT ...................................................................................................................... xi CHAPTER 1 GENERAL INTRODUCTION ..................................................................................... 1 Life-History Strategies................................................................................................ 1 Life-History Strategies: Study Objectives................................................................... 2 2 TROPICAL FOREST DIVERSITY AND HABITAT ASSOCIATIONS: COMMUNITY VERSUS SPECIES PATTERNS ........................................................ 5 Introduction ................................................................................................................ 5 Materials and Methods............................................................................................... 9 Study Site............................................................................................................ 9 Vegetation......................................................................................................... 10 Soils and Light................................................................................................... 11 Analyses............................................................................................................ 12 Results ..................................................................................................................... 14 Environment...................................................................................................... 14 Vegetation: Community Response.................................................................... 16 Vegetation: Species Associations..................................................................... 17 Discussion................................................................................................................ 18 3 DO LIFE-HISTORY CHARACTERS OF JUVENILE TREES AND SHRUBS REFLECT ADAPTATIONS TO CONTRASTING HABITATS?................................. 37 Introduction .............................................................................................................. 37 Materials and Methods............................................................................................. 40 Study Site.......................................................................................................... 40 Methods ............................................................................................................ 40 Analyses............................................................................................................ 43 Results ..................................................................................................................... 45 Life-History Character Variation........................................................................ 45 Cotyledon Types and Other Categorical Variables........................................... 46 Mean Character Comparisons among Discrete Categories.............................. 47 v Seed Mass and Continuous Variables.............................................................. 48 Multivariate Analyses ........................................................................................ 48 Phylogenetic Effects.......................................................................................... 49 Discussion................................................................................................................ 51 Cotyledon Type................................................................................................. 51 Seed Size.......................................................................................................... 55 Suites of Characters.......................................................................................... 57 Juvenile Characters and Environmental Associations ...................................... 57 Phylogeny ......................................................................................................... 58 Conclusions....................................................................................................... 59 4 ADAPTATION AND VARIATION OF TREE AND SHRUB SEEDLINGS: SURVIVAL AND GROWTH ACROSS HABITATS................................................... 69 Introduction .............................................................................................................. 69 Materials and Methods............................................................................................. 72 Study Site.......................................................................................................... 72 Methods ............................................................................................................ 73 Analyses............................................................................................................ 75 Results ....................................................................................................................