University of Florida Thesis Or Dissertation
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DISTRIBUTIONAL ECOLOGY AND DIVERSITY PATTERNS OF TROPICAL MONTANE BIRDS By JILL EMILY JANKOWSKI 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 2010 1 © 2010 Jill Emily Jankowski 2 To my parents, Mike and Laverne, and my loving and adorable partner in crime, Aaron 3 ACKNOWLEDGMENTS This dissertation would not have been possible without the unwavering dedication and guidance from my co-advisors and committee, the long months of work contributed by my assistants, the logistical and financial support of many people and organizations, both in the United States and abroad, and the patience and encouragement from loved ones throughout this six-year endeavor. My advisors, Doug Levey and Scott Robinson, have been terrific role models in academics and teaching, and their dedication to family serves as an example of how to keep the most important things in perspective. The members of my committee, including R. Holt, S. Phelps, and K. Sieving, were extremely supportive and gave constructive feedback on all aspects of the dissertation. Many people worked in the field with me and assisted in data collection, often for months on end, including T. Boza, R. Butrón, L. M. Cabrera, R. Cruz, K. Elliot, V. Huamán, M. Jurado, M. Libsch, G. Londoño, J. Olano, Z. Peterson, N. Quisiyupanqui, R. Quispes, M. Salazar, S. J. Socolar, A. Spalding, J. Ungvari-Martin, and C. Zurita. I thank the Campbell, Cruz, Guindon, Leitón, Lowther, Morrison, Rockwell and Stuckey families of Monteverde for allowing me to work on their properties, and the Monteverde and Santa Elena cloudforest preserves, the Monteverde Conservation League, Bosque Eterno, and Monteverde Biological Station for granting permission to work in these protected areas. K. Rabenold helped enormously with logistics in Monteverde, and I am very grateful for the academic and emotional support he has continued to provide over the years, as a friend and colleague. The staff of Parque Nacional Manu, Asociación para la Conservación de la Cuenca Amazonica (ACCA) and Peru Verde made field research possible in Peru. I thank the Dirección General de Areas Naturales Protegidas y Flora y Fauna Silvestre of INRENA, which 4 provided permits for research and exportation of samples. M. Silman, N. Salinas, W. Farfan, K. Garcia, and L. Imunda blazed the trails, literally, for much of our work in Peru, and let me tag along on adventures to other beautiful corners of Manu. Many thanks to D. Willard and the staff at the Field Museum of Chicago for use of the bird collections, and to D. Stotz, D. Lane, S. Herzog, J. Tobias and R. Yaber for help with identification of Andean bird songs. A. Spalding built microphones, repaired mistreated electronic equipment, and at one point recovered data from failed hard drives. Thanks to K. Rabenold, C. Stracey, G. Londoño and J. Terborgh for comments on various dissertation chapters and to B. Bolker, J. Poulsen and C. Clark for statistical advice. Funding was received from a University of Florida Alumni Fellowship, the Animal Behavior Society, Sigma Xi, the American Ornithologists’ Union, ACCA, the National Aeronautical and Space Administration, and the National Science Foundation. 5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ...................................................................................................... 4 LIST OF TABLES ................................................................................................................ 9 LIST OF FIGURES ............................................................................................................ 10 ABSTRACT........................................................................................................................ 11 CHAPTER 1 INTRODUCTION ........................................................................................................ 13 2 A MECHANISTIC APPROACH TO ELEVATIONAL RANGES OF TROPICAL BIRDS ......................................................................................................................... 16 Introduction ................................................................................................................. 16 Defining the Physiological Niche for Montane Species ............................................. 20 Physiological Constraints on Range Limits at Different Life History Stages ...... 23 Predicted Adaptations in Physiological Tolerances along Elevational Gradients ........................................................................................................... 24 Biotic Challenges for Montane Species ..................................................................... 26 Predation Risk along Elevational Gradients........................................................ 26 Competitive Interactions and Species Replacements ........................................ 28 Mutualistic Interactions in Mixed-Species Flocks ............................................... 32 Habitat Structure and Vegetation ........................................................................ 33 Modeling Species Distributions to Test Abiotic and Biotic Effects on Ranges ......... 35 Scenarios of Climate Change Impacts for Tropical Montane Species ..................... 37 Conclusions ................................................................................................................ 40 3 RANGE SIZES AND RESPONSE SHAPES OF TROPICAL BIRDS ALONG AN ANDEAN ELEVATIONAL GRADIENT ....................................................................... 42 Introduction ................................................................................................................. 42 Methods ...................................................................................................................... 45 Study Site ............................................................................................................. 45 Bird Surveys ......................................................................................................... 46 Data Analyses ...................................................................................................... 48 Results ........................................................................................................................ 50 Elevational Range Sizes ...................................................................................... 50 Species Response Curves and Position of Range Boundaries ......................... 52 Discussion ................................................................................................................... 55 Elevational Range Sizes ...................................................................................... 56 Species Response Shapes and Positions of Range Boundaries ...................... 58 Conclusion ............................................................................................................ 62 6 4 THE RELATIONSHIP OF TROPICAL BIRD COMMUNITIES TO TREE COMPOSITION AND VEGETATION STRUCTURE ALONG AN ANDEAN ELEVATIONAL GRADIENT ....................................................................................... 68 Introduction ................................................................................................................. 68 Methods ...................................................................................................................... 71 Study Region ........................................................................................................ 71 Tree Censuses ..................................................................................................... 73 Bird Surveys ......................................................................................................... 73 Vegetation Structure ............................................................................................ 74 Avian Feeding Guild Classification ...................................................................... 75 Data Summary and Analyses .............................................................................. 75 Results ........................................................................................................................ 78 Species Richness................................................................................................. 78 Patterns of Species Occurrence, Nestedness and Turnover ............................. 79 Taxonomic Congruence in Birds and Trees with Elevation ................................ 80 Explanation of Bird Dissimilarity by Vegetation Structure, Elevation and Trees ................................................................................................................. 82 Discussion ................................................................................................................... 84 Species Richness Patterns in Birds and Trees ................................................... 84 Species Turnover, Nestedness and Patterns of Compositional Similarity ......... 86 Importance of Tree Composition, Vegetation Structure and Elevation .............. 89 Prospects for Montane Birds and Trees with Climate Change .......................... 90 5 SQUEEZED AT THE TOP: INTERSPECIFIC COMPETITION MAY CONSTRAIN ELEVATIONAL RANGES IN TROPICAL BIRDS ............................. 101 Introduction ..............................................................................................................