MULTI-SCALE INVESTIGATIONS OF GRAY TREEFROG MOVEMENTS: PATTERNS OF MIGRATION, DISPERSAL, AND GENE FLOW ___________________________________________________ A Dissertation presented to the Faculty of the Graduate School University of Missouri-Columbia ___________________________________________________ In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy ___________________________________________________ by JARRETT REED JOHNSON Dr. Raymond Semlitsch, Dissertation Supervisor JULY 2005 The undersigned, appointed by the Dean of the Graduate School, have examined the dissertation entitled MULTI-SCALED INVESTIGATIONS OF GRAY TREEFROG MOVEMENTS: PATTERNS OF MIGRATION, DISPERSAL, AND GENE FLOW presented by Jarrett R. Johnson a candidate for the degree of Doctor of Philosophy and hereby certify that in their opinion it is worthy of acceptance. ACKNOWLEDGEMENTS I have been fortunate to be a part of a large group of students that shared very similar research interests as myself. Never has there been a time in my tenure as a graduate student that advice or other assistance was unavailable from other members of the Semlitsch lab. For this I am grateful to all the current and former lab members (especially Betsie Rothermel and Tracy Rittenhouse) for participating in helpful discussions regarding research projects and reviewing manuscripts. I also thank John Crawford, Chris Conner, Elizabeth Harper, Bethany Williams, Sara Storrs, and Dan Hocking for all their assistance in the field and in the lab. I have also benefited greatly from having Ray Semlitsch as an advisor. He was always available to provide guidance, and eagerly awaited progress reports (especially if I was working on a manuscript). I often wondered how he got any of his own work done considering the constant pestering by his graduate students. Nevertheless, his excitement for the research of his students is readily apparent, and he has greatly facilitated my ability to improve upon the skills that make a good scientist. I also am indebted to my committee (Carl Gerhardt, Tim Holtsford, Mark Ryan, and Chris Phillips) both for their support and for critically reading this gratuitously long dissertation. I would specifically like to thank Carl for sharing his knowledge of the gray treefrog and for believing I saw a rattlesnake on the herpetology field trip (it wasn’t a stick!). I especially thank Tim for allowing me to parasitize his lab space for my early genetic work, and for his constant ii willingness to help. I am grateful to Chris for counsel regarding my struggles with generating and analyzing tetraploid genetic data and for sharing insight regarding the proper way to catch a hellbender. I thank Mark for providing the perspective of a conservation biologist and for his efforts to produce particularly useful suggestions on the chapters of this dissertation. For numerous activities ranging from manual labor to tedious data entry I give sincere thanks to the enthusiastic undergraduates Rachel Mahan, Rachel Mank, and Jeff Haynes. I am also grateful to Chad Rittenhouse, Oli Beckers, and Richard Daniel for help both in the field and in the lab. Many others have also contributed to my genetic work, including Dean Bergstrom, Ellen Krueger, Gordon Burleigh, Karen Cone, Tiffanie Hamilton, Jim Birchler, and Kathy Newton. I thank Jim Carrel for hallway pleasantries and his ‘stockroom’ of miscellaneous supplies and equipment, and Mary Jackson for invertebrate identification. Sarah Mathews has been instrumental in my most recent genetic work by providing lab space and sage advice, not to mention croquet (not crochet) lessons. I am most definitely thankful for the overwhelming support of my family and friends. My wife, Gina, deserves this degree as much as I do. For her help during the construction of the cattle tank arrays and marking of metamorphs I am forever indebted, and when it comes to organization of data she is a wizard. She was always willing to help in any way that she could, and her support has meant more to me than I could ever put into words. I am grateful to my mom, Dianne, for teaching me the determination to finish what I started (even if it meant wearing tight pants) and for encouraging my education at all stages. I thank my dad, Darrell, for instilling in me an enthusiasm for iii wildlife and for providing the opportunity to explore the natural world. Our ‘road- runnin’ trips to catch herps in the rain were the start of all this madness (I still haven’t told mom that I sat on the hood!). I am lucky to have found the friends that I have made as a graduate student, and these past six years would have been far more miserable without their (you know who you are) support and camaraderie. I would be remiss not to mention several by name, most notably Marc Brock, Casey Dillman, and Scott Rothermel. I thank these charter members of a secret society, along with Dorsal McGill, for providing much needed distractions and debauchery over the years. I probably could have finished faster without them, but it wouldn’t have been as much fun. Some of these words are theirs. iv TABLE OF CONTENTS ACKNOWLEDGEMENTS.............................................................................................ii LIST OF TABLES .........................................................................................................ix LIST OF FIGURES........................................................................................................xi ABSTRACT.................................................................................................................xiv Chapter 1. DEFINING CORE HABITAT OF LOCAL POPULATIONS OF THE GRAY TREEFROG (HYLA VERSICOLOR) BASED ON CHOICE OF OVIPOSITION SITE Abstract...................................................................................................................1 Introduction.............................................................................................................2 Methods...................................................................................................................4 Results.....................................................................................................................7 Discussion ...............................................................................................................8 Acknowledgements ...............................................................................................13 Literature Cited......................................................................................................14 2A. SEX AND SEASONAL DIFFERENCES IN TERRESTRIAL DISTRIBUTIONS AND CORE HABITAT ESTIMATES FOR POPULATIONS OF THE GRAY TREEFROG (HYLA VERSICOLOR) Abstract.................................................................................................................29 Introduction...........................................................................................................30 Methods.................................................................................................................34 Results...................................................................................................................38 Discussion .............................................................................................................41 v Acknowledgements ...............................................................................................50 Literature Cited......................................................................................................51 2B. BIOTIC AND ABIOTIC FACTORS AFFECTING TERRESTRIAL MICROHABITAT USE BY GRAY TREEFROGS (HYLA VERSICOLOR): EVIDENCE FROM ARTIFICIAL ARBOREAL RETREATS AND RADIOTRACKING Abstract.................................................................................................................70 Introduction...........................................................................................................71 Methods.................................................................................................................75 Results...................................................................................................................78 Discussion .............................................................................................................81 Acknowledgements ...............................................................................................86 Literature Cited......................................................................................................87 3. EFFECT OF INTER-POND DISTANCE AND MATRIX HABITAT ON MOVEMENTS OF THE GRAY TREEFROG, HYLA VERSICOLOR, IN EXPERIMENTAL POND ARRAYS Abstract...............................................................................................................106 Introduction.........................................................................................................107 Methods...............................................................................................................111 Results.................................................................................................................115 Discussion ...........................................................................................................118 Acknowledgements .............................................................................................126 Literature Cited....................................................................................................127