MICROHABITAT SELECTION IN THE EASTERN WORM SNAKE (CARPHOPHIS AMOENUS) AND A SURVEY OF THE AMPHIBIANS AND REPTILES OF HUNTLEY MEADOWS PARK, ALEXANDRIA, VIRGINIA by Kara S. Jones, M.S. A Thesis Submitted to the Graduate Faculty of George Mason University in Partial Fulfillment of The Requirements for the Degree of Master of Science Environmental Science and Policy Committee: __________________________________________ Dr. Larry L. Rockwood, Thesis Director __________________________________________ Dr. Arndt F. Laemmerzahl, Committee Member __________________________________________ Dr. David Luther, Committee Member __________________________________________ Dr. Albert P. Torzilli, Graduate Program Director __________________________________________ Dr. Robert B. Jonas, Department Chairperson __________________________________________ Dr. Donna Fox, Associate Dean, Student Affairs & Special Programs, College of Science __________________________________________ Dr. Peggy Agouris, Dean, College of Science Date: _____________________________________ Spring Semester 2015 George Mason University Fairfax, VA Microhabitat Selection in the Eastern Worm Snake (Carphophis amoenus) and a Survey of the Amphibians and Reptiles of Huntley Meadows Park, Alexandria, Virginia A Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at George Mason University by Kara S. Jones, M.S. Bachelor of Science George Mason University, 2013 Director: Larry L. Rockwood, Professor Department of Environmental Science and Policy Spring Semester 2015 George Mason University Fairfax, VA This work is licensed under a creative commons attribution-noderivs 3.0 unported license. ii ACKNOWLEDGEMENTS This thesis could not have been completed without the help of many people, so I have many people to thank. In no particular order: My mom (Cindy Jones) and Iain Curtain for financial and moral support; Dave Lawlor, Karen Sheffield, Kevin Munroe and the rest of the staff and volunteers at Huntley Meadows Park for working on herp surveys; Tatiana Galitzin, James Sinks, Jenna Wingfield and Joel Mota for help with worm snake wrangling; Rob Aguilar for help getting the project started; Emma Boyle for tipping me off to Jug Bay’s worm snakes and Elaine Friebele for approving my research there; David Luther and OSCAR for supporting this project with mentorship and money; and last, but definitely not least, Todd Tupper for inspiring my love of herps and encouraging me to reach my potential. iii TABLE OF CONTENTS Page List of Tables ..................................................................................................................... vi   List of Figures ................................................................................................................... vii   List of Abbreviations and Symbols .................................................................................. viii   Abstract .............................................................................................................................. ix   Chapter One: Factors affecting microhabitat selection in the eastern worm snake (Carphophis amoenus) ........................................................................................................ 1   Introduction ..................................................................................................................... 1   Materials and Methods .................................................................................................... 4   Study Sites ................................................................................................................... 4   Snake Searches and Measurements ............................................................................. 4   Microhabitat Measurements ........................................................................................ 5   Statistical Analyses ...................................................................................................... 8   Results ............................................................................................................................. 9   Discussion ..................................................................................................................... 20   Conclusion ..................................................................................................................... 23   Chapter Two: Census of the amphibians and reptiles of Huntley Meadows Park, Alexandria, Virginia ......................................................................................................... 25   Introduction ................................................................................................................... 25   Materials and Methods .................................................................................................. 26   Study Site ................................................................................................................... 26   Time-Constrained Searches ....................................................................................... 27   Anuran Calling Surveys ............................................................................................. 28   Vernal Pool Monitoring ............................................................................................. 28   Visual Encounter Surveys ......................................................................................... 29   Mark-Recapture of Spotted Turtles (Clemmys guttata) ............................................ 30   Landscape Analyses .................................................................................................. 30   iv Results ........................................................................................................................... 31   Annotated Species List .................................................................................................. 36   Frogs .......................................................................................................................... 39   Salamanders ............................................................................................................... 42   Turtles ........................................................................................................................ 44   Lizards ....................................................................................................................... 47   Snakes ........................................................................................................................ 48   Discussion ..................................................................................................................... 50   Conclusion ..................................................................................................................... 56   Appendix ........................................................................................................................... 57   Background ................................................................................................................... 57   Methods ......................................................................................................................... 57   Taking digital images ................................................................................................ 57   Analyzing canopy cover ............................................................................................ 58   Analyzing ground cover ............................................................................................ 59   References ......................................................................................................................... 62   v LIST OF TABLES Table Page 1-1. Decay classification scheme for coarse woody debris............................................... 6 1-2. Morphological characteristics for captured C. amoneus............................................ 11 1-3. Microclimate characteristics of used and available coarse woody debris refugia...... 12 1-4. Structural microhabitat characteristics surrounding used and available coarse woody debris refugia......................................................................................................... 16 2-1. Results of time-constrained searches in Huntley Meadows Park............................... 32 2-2. Change in land cover from 1992 to 2011 within Huntley Meadows Park................. 36 2-3. Change in land cover from 1992 to 2011 in a 1000 m buffer surrounding Huntley Meadows Park................................................................................................................... 36 2-4. List of species historically recorded in the park and their current status................... 37 2-5. Habitat preferences for amphibians and reptiles found in Huntley Meadows Park... 53 vi LIST OF FIGURES Figure Page 1-1. Map of Huntley Meadows Park.................................................................................. 10 1-2. Map of Jug Bay Wetlands Santuary........................................................................... 10 1-3. Temperatures of refuges where Carphophis amoenus were captured, divided by sex...................................................................................................................................... 13 1-4. Temperatures within refuges and ambient air temperatures throughout both field seasons............................................................................................................................... 14 1-5. Refuge temperatures increased as a function of ambient air temperatures................ 15 1-6. Proportion of C. amoenus captured in each CWD decay class.................................. 17 1-7. Proportion of invertebrates found at used and available refuge sites......................... 17 1-8. Refuge and soil temperature (~50 cm depth) compared to preferred temperature range for Carphophis amoenus.......................................................................................... 19 2-1. Map of Huntley Meadows Park, Alexandria, Virginia, showing the location of major wetlands, meadows, forest, and formal and informal trails surveyed for amphibians and reptiles..................................................................................................... 27 2-2. Maximum calling intensity heard for ten species during anuran calling surveys in the main wetland................................................................................................................ 23 2-3. Change in and around Huntley Meadows Park between 1992 and 2011................... 35 A-1. Digital image of canopy cover before and after manipulation.................................. 59 A-2. Digital image of ground cover before and after manipulation.................................. 61 vii LIST OF ABBREVIATIONS AND SYMBOLS Meters ................................................................................................................................ m Celsius ................................................................................................................................. C Hectares .............................................................................................................................. ha Coarse Woody Debris .................................................................................................. CWD Huntley Meadows Park ................................................................................................. HMP Jug Bay Wetlands Sanctuary ............................................................................................ JB viii ABSTRACT MICROHABITAT SELECTION IN THE EASTERN WORM SNAKE (CARPHOPHIS AMOENUS) AND A SURVEY OF THE AMPHIBIANS AND REPTILES OF HUNTLEY MEADOWS PARK, ALEXANDRIA, VIRGINIA Kara S. Jones, M.S. George Mason University, 2015 Thesis Director: Dr. Larry L. Rockwood The eastern worm snake (Carphophis amoenus) is a fossorial species that often uses coarse woody debris (CWD) refuges when it is not beneath the ground. The purpose of this study was to determine whether CWD the worm snakes select as refugia differ from available CWD within the microhabitat. This study took place at Huntley Meadows Park, Alexandria, Virginia, and Jug Bay Wetlands Sanctuary, Lothian, Maryland. Snakes were found by searching CWD refuges. Microclimate, ground cover and canopy cover measurements were taken at used and available refuges. There was no significant difference between refuges selected by different sexes or by individuals undergoing ecdysis and the general population. Refuge temperatures were significantly lower than ambient air temperatures, but there was no significant difference between the microclimate characteristics of used and available refuges. Used refuges had significantly more decayed CWD and a higher proportion of CWD cover. They were ix