FACTORS AFFECTING the DISTRIBUTION of the ENDANGERED SHENANDOAH SALAMANDER (PLETHODON SHENANDOAH) By
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FACTORS AFFECTING THE DISTRIBUTION OF THE ENDANGERED SHENANDOAH SALAMANDER (PLETHODON SHENANDOAH) by Jennifer A. Sevin A Dissertation Submitted to the Graduate Faculty of George Mason University in Partial Fulfillment of The Requirements for the Degree of Doctor of Philosophy Environmental Science and Public Policy Committee: _________________________________________ Dr. Larry Rockwood, Dissertation Director _________________________________________ Dr. Chris Parsons, Committee Member _________________________________________ Dr. Thomas Wood, Committee Member _________________________________________ Dr. Larissa Bailey, Committee Member _________________________________________ Dr. Jesus Maldonado, Committee Member _________________________________________ Dr. Albert Torzilli, Graduate Program Director _________________________________________ Dr. Robert Jonas, Department Chairperson _________________________________________ Dr. Richard Diecchio, Interim Associate Dean for Student and Academic Affairs, College of Science _________________________________________ Dr. Peggy Agouris, Interim Dean, College of Science Date: __________________________________ Spring Semester 2014 George Mason University Fairfax, VA Factors Affecting the Distribution of the Endangered Shenandoah Salamander (Plethodon Shenandoah) A Dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at George Mason University by Jennifer A. Sevin Director: Larry Rockwood, Professor Department of Environmental Science and Public Policy Spring Semester 2014 George Mason University Fairfax, VA This work is licensed under a creative commons attribution-noderivs 3.0 unported license. ii DEDICATION This is dedicated to the memory of my mom for her strength, drive and passion. She instilled those values in me and I hope to pass them on to Taylor so that she can weather the storms and create her own rainbows. iii ACKNOWLEDGEMENTS I would like to thank the many friends, relatives and supporters who have taken this llllloooooonnnnnnggggg journey with me. I bet ya’ll never thought it would happen….neither did I at times. I wish my Mom was around to witness her child who always hated school finally finishes with a Ph.D. Dad and Scott, despite my trials and tribulations, you have never stopped loving and believing in me. What more could I ask for? I will miss your daily reminders that I have a dissertation to complete….NOT. To my wonderful boyfriend, Derek, thank you for the encouragement, love and support, and of course, the cooking and cleaning. I probably would have gotten this done a lot sooner if you were not in the picture, but I am thankful everyday for having you and Taylor as part of my family. You helped me realize there is more to life than work. Andrew, Matthew, Kasey, Trish, Adrianne and the many others….what can I say? I had the best field crew and support in the world. You not only worked on this project as if it was your own, but you kept me from falling off mountains (literally and figuratively). You will always have a special place in Mama Bear’s heart. Thank you Jason for the daunting task of helping me with GIS. There are too many people at the Smithsonian that provided encouragement to name them all, but I need to mention Steve Monfort and Francisco Dallmeier for being particularly supportive of me during the long process, and to Marshall Jones for being an exceptional mentor. Much appreciation to all my committee members for gently pushing me forward. Dr. Rockwood, I hope to one day emulate how you successfully accomplish countless tasks with a smile on your face and a positive attitude. This research would not have been possible without the tremendous in-kind support and funding from the U.S. Geological Survey, National Park Service, Virginia Department of Game and Inland Fisheries and Smithsonian Institution. I would particularly like to thank Jim Atkinson, Jeb Wofford and Alan Williams of NPS and J.D. Kleopfer of VDGIF. Thanks for your help and patience. You have no idea how happy I am that the Shenandoah salamander did not go extinct while you waited for my results. And last, but certainly not least, to the amazing support of N.E. ARMI: Larissa Bailey for getting this project off the ground and helping carry it through to the end, and Evan Grant for his invaluable contributions at every stage of the process. I am truly in debt. iv TABLE OF CONTENTS Page List of Tables .................................................................................................................... vii List of Figures .................................................................................................................... ix Abstract .............................................................................................................................. xi General Introduction ........................................................................................................... 1 Study species ................................................................................................................... 3 Study Area ....................................................................................................................... 5 Occupancy Modeling and Multi-model Inference .......................................................... 5 Literature Cited ............................................................................................................... 9 Chapter 1 - Optimal survey design: Maximizing the probability of detection for an endangered high elevation salamander ............................................................................. 14 Introduction ................................................................................................................... 14 Methods ......................................................................................................................... 18 Hypotheses .................................................................................................................... 23 Results ........................................................................................................................... 24 Discussion ..................................................................................................................... 28 Management Implications ............................................................................................. 34 Appendix 1A ................................................................................................................. 35 Literature Cited ............................................................................................................. 37 Chapter 2 - Investigating distribution and habitat-related hypotheses of the endangered Shenandoah salamander (Plethodon shenandoah). .......................................................... 43 Introduction ................................................................................................................... 43 Hypotheses .................................................................................................................... 45 Methods ......................................................................................................................... 49 Results ........................................................................................................................... 55 Discussion ..................................................................................................................... 66 Management Implications ............................................................................................. 73 v Appendix 2A ................................................................................................................. 76 Appendix 2B ................................................................................................................. 78 Literature Cited ............................................................................................................. 81 Chapter 3 - Do P. shenandoah and P. cinereus actually compete? .................................. 87 Introduction ................................................................................................................... 87 Methods ......................................................................................................................... 93 Results ........................................................................................................................... 99 Discussion ................................................................................................................... 109 Management Implications ........................................................................................... 115 Appendix 3A ............................................................................................................... 117 Appendix 3B ............................................................................................................... 119 Appendix 3C ............................................................................................................... 121 Appendix 3D ............................................................................................................... 123 Appendix 3E ................................................................................................................ 125 Literature Cited ..........................................................................................................