THE POTENTIAL FOR SPREAD OF A NOVEL INVADER, THE TROPICAL CLAWED FROG (Xenopus tropicalis), IN FLORIDA By COLIN M. GOODMAN A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2020 © 2020 Colin M. Goodman To my family ACKNOWLEDGMENTS I would like to thank my family and friends for all of the support during this process. I would also like to thank my spouse, Olivia, for all of her support and assistance in editing this thesis. I would like to thank my advisor, Dr. Christina Romagosa, for helping me to develop this project, as well as the tremendous amount of support she has provided me. I would like to thank my committee members, Drs. Jeffrey Hill, Steve Johnson, and Miguel Acevedo, for their time, material support, and their invaluable input on my thesis. Another thanks to Dr. Quenton Tuckett for his guidance on the analyses. Thanks to Dr. Anthony Herrel for his input on locomotor performance methodology. I am extremely grateful to the Florida Fish and Wildlife Conservation Commission for funding; without this funding, this project would not have materialized. Further, thanks to Daniel Quinn, Clinton Cunningham, and Tyson Dallas for providing preliminary data. I would like to thank Craig Watson, Amy Wood, Micah Alo, and all others at the University of Florida Aquaculture Laboratory. They offered material supplies, as well as a venue for the conduction of all laboratory research associated with this research. I would also like to thank Dr. Bob Reed and the United States Geological Survey for the material support. Thanks to Katie Buckman, Lauren Lapham, and Dr. Allison Durland, for their assistance with field work and animal husbandry. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 7 LIST OF FIGURES .......................................................................................................... 8 LIST OF ABBREVIATIONS ............................................................................................. 9 ABSTRACT ................................................................................................................. 111 CHAPTER 1 BACKGROUND ON THE EXTANT INVASION OF THE TROPICAL CLAWED FROG IN WEST-CENTRAL FLORIDA ................................................................... 13 General Introduction ............................................................................................... 13 Invasion History ...................................................................................................... 14 The Current Invasion .............................................................................................. 16 Research Objectives ............................................................................................... 17 2 DISPERSAL, MORPHOLOGY, AND LOCOMOTOR PERFORMANCE OF TROPICAL CLAWED FROGS IN WEST-CENTRAL FLORIDA .............................. 21 Synopsis ................................................................................................................. 21 Background ............................................................................................................. 22 Study Area .............................................................................................................. 24 Methods .................................................................................................................. 25 Field Sampling .................................................................................................. 25 Marking............................................................................................................. 26 Performance Assays ........................................................................................ 28 Maximal exertion capacity .......................................................................... 28 Jumping performance ................................................................................ 29 Morphology ....................................................................................................... 30 Data Analysis ................................................................................................... 31 Results .................................................................................................................... 32 Discussion .............................................................................................................. 36 3 CLIMATIC AND HABITAT SUITABILITY FOR INVASION OF THE TROPICAL CLAWED IN FLORIDA ........................................................................................... 57 Synopsis ................................................................................................................. 57 Background ............................................................................................................. 58 Methods .................................................................................................................. 60 5 Compiling Occurrence Records ........................................................................ 60 Variable Selection and Manipulation ................................................................ 61 Sampling Bias .................................................................................................. 64 Model Construction and Tuning ........................................................................ 66 Model Projection and Constraining ................................................................... 69 Results .................................................................................................................... 71 Model Evaluation .............................................................................................. 71 Model Projection and Transfer ......................................................................... 72 Model Constraining .......................................................................................... 73 Discussion .............................................................................................................. 74 4 CONCLUSION ........................................................................................................ 91 LIST OF REFERENCES ............................................................................................. 966 BIOGRAPHICAL SKETCH .......................................................................................... 118 6 LIST OF TABLES Table page 2-1 Pairwise correlations between each caliper-based measurement and its pictorial extracted analogue. ............................................................................... 50 2-2 Mean and standard deviation of morphometric measurements used in models, split up by sex and dispersal status ...................................................... 51 2-3 Mean and standard deviation of performance trait values, split up between sex and dispersal status ..................................................................................... 51 2-4 Mean and standard deviation of jumping trial values, split up between sex and dispersal status ............................................................................................ 51 2-5 Rankings of all candidate logistic regression models using only frogs that had dispersed or remained at the same site for an entire dry season (N=92) ........... 52 2-6 Summary from the top model from the candidate set in Table 2-5 ..................... 52 2-7 Rankings of all candidate logistic regression models linking maximal exertion capacity to dispersal status (N=84) .................................................................... 54 2-8 Summary of the conditional results from the subset of top-performing models Table 2-7 ............................................................................................................ 54 2-9 Rankings of all candidate logistic regression models from the jumping performance trials (N=90) ................................................................................... 55 3-1 Descriptions of all variables used in ENMs, and the reasoning for their inclusion ............................................................................................................. 80 3-2 Legend of all the categories inclued in the GlobCover dataset (from Bicheron et al., 2013)......................................................................................................... 82 3-3 Summary of thermal buffer data gathered from temperature logger data. .......... 84 3-4 Table showing performance metrics of all models evaluated. ............................ 84 3-5 All terms used in the top-performing model. ....................................................... 85 3-6 Relative suitability scores across all sites within the invaded range where X. tropicalis has been detected ............................................................................... 90 7 LIST OF FIGURES Figure page 1-1 Dorsal view of the skeleton (Field ID CMG-111) based on a CT scan.. .............. 19 1-2 Map of detections and non-detections of X. tropicalis in Riverview, Florida ....... 20 2-1 Collage showing the variation in sites within the study area ............................... 44 2-2 Map of