UNIVERSITY OF CALIFORNIA Santa Barbara Decline, Movement and Habitat Utilization of the Yosemite Toad (Bufo canorus): An Endangered Anuran Endemic to the Sierra Nevada of California A Dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Ecology, Evolution and Marine Biology by David Lamar Martin Committee in charge: Professor Samuel S. Sweet, Chair Professor Steve I. Rothstein Professor Allan Stewart-Oaten June 2008 3319824 Copyright 2008 by Martin, David Lamar All rights reserved 3319824 2008 The dissertation of David Lamar Martin is approved. _____________________________________________ Allan Stewart-Oaten _____________________________________________ Steve I. Rothstein _____________________________________________ Samuel S. Sweet, Committee Chair June 2008 Decline, Movement and Habitat Utilization of the Yosemite Toad (Bufo canorus): An Endangered Anuran Endemic to the Sierra Nevada of California Copyright © 2008 by David Lamar Martin iii ACKNOWLEDGEMENTS “The (Yosemite toads) that live on my (forest) are reluctant to tell me, in so many words, how much of my township is included within their daily or nightly beat. I am curious about this, for it gives me the ratio between the size of their universe and the size of mine, and it conveniently begs the much more important question, who is the more thoroughly acquainted with the world in which he lives? Like people, my (toads) frequently disclose by their actions what they decline to divulge in words. It is difficult to predict when and how one of these disclosures will come to light.” With apologies to Aldo Leopold, and A Sand County Almanac, 1949, p. 78. I am indebted to Dr. Sam Sweet, my dissertation committee chair and major professor, for allowing me the freedom to learn how to conduct science rather than spoon feeding it to me. His example and wisdom in wading through endangered anuran research and the trials and tribulations that come with it, have been formative. For his comments, suggestions and support of my research I will be forever grateful. I also extend my sincere gratitude to my other dissertation committee members, Dr. Steve Rothstein, Dr. Allan Stewart-Oaten and early on Dr. John Endler. I thank Dr. Rothstein for the many conversations and suggestions early in my time at UCSB that helped guide the direction of my research, for his careful review and helpful suggestions on this dissertation and for filling in as faculty advisor when Dr. iv Sweet was away on sabbatical. I thank Dr. Stewart-Oaten who contributed a great deal of help with the statistical analysis and graciously stepped up and filled out my committee during the final stretch. I thank Dr. Endler who helped me develop the theoretical perspective under which I tackled my research and provided helpful comments on the first chapter of this dissertation before he retired. Finally, for her judicious application of a cattle prod that forced me to put a period on this albatross, I thank my Graduate Advisor, Dr. Gretchen Hofmann. Major funding for this research project was provided by a U.S. Fish and Wildlife Service, Endangered Species Division research grant (#10181-5-1919) supervised by Amadee Brikey, Diane Windham and Steven Morey. Without this funding, and the support of Kathy, Diane and Steve this project would have never gotten off the ground. Additional funding for this research and personal support was provided by my parents, Mr. and Dr. George and Patty Martin, and grandparents, Dr. and Mrs. Lamar and Marguerite Fryer. Personal support was also provided by my brother and sister, Jeff Martin and Debbie Martin. I cannot thank my family enough for sticking by me throughout this process, and especially through the difficult times. The intensive four years of field work would not have been possible without the assistance and enthusiasm of the field research assistants who generously gave of their time and energies to help me complete this project. First among them is Paulo Philippidis who stuck with me through two long field seasons. For hiking miles in the snow to get to research sites early in the season, for slogging through mud and cow pies, for tolerating 18 to 20 hour periods of nonstop work without complaining (much) and for tolerating temperatures ranging from over 32°C to less than -22°C I v cannot thank you enough! Additional field assistance, for which I am eternally grateful, was provided by Donna Clifton, Brenden Borell and Alan McCready. My two office mates, David Greenberg and John LaBonte, and fellow grad Rocky Strong provided much needed feedback on research ideas, methods of analysis and social interaction. The next round is on me guys. I would be remiss if I did not thank Dr. Ernest L. Karlstrom, Dr. Martin L. Morton and Dr. Cynthia Kagarise Sherman for their formative research on which my dissertation is based. Dr. Karlstrom and Dr. Morton were also kind enough to spend many days with me in the field showing me their research sites and providing invaluable insights into the behavior of the Yosemite toad. Thank you very much gentlemen. In addition to assistance with field work, my good friend Alan McCready also generously shared his historical knowledge of Yosemite toad breeding activities and distribution throughout the research project area. Thanks Alan. I also thank Tom Beck of Stanislaus National Forest who helped with logistical support and assistance in working through Forest Service bureaucracy. Finally, there are no words to adequately thank the two women in my life who believed in me no matter what, and who provided me with never-ending love and support: my mother, Dr. Patty M. Martin, and my fiancée, Miss Sara E. Johnson. It is to these two women that I dedicate my dissertation. Ladies, I kept my promise and stuck with it! vi VITA OF DAVID LAMAR MARTIN June 2008 EDUCATION Bachelor of Science in Biological Science with a Concentration in Zoology, San Jose State University, San Jose, California, May 1989 Master of Arts in Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California, June 2006 Doctor of Philosophy in Ecology, Evolution and Marine Biology, University of California, Santa Barbara, June 2008 (expected) PROFESSIONAL EMPLOYMENT 1992-2008: Consultant, Environmental and Wildlife Law Enforcement Canorus Ltd., San Jose, California 1993-2002: Teaching Assistant, Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara 1995-2000: Covert Investigator, Division of Law Enforcement, Branch of Special Operations, U.S. Department of Fish and Wildlife, Burlingame, California 1993: Student Research Associate, Sansum Medical Research Foundation, Santa Barbara, California 1990-92: Research Assistant, Osher Molecular Systematics Laboratory, California Academy of Sciences, San Francisco, California 1991: Instructor, Vertebrate Museum Methods, Department of Biology, San Jose State University, San Jose, California 1986-92: Assistant Curator, Museum of Birds and Mammals, Department of Biology, San Jose State University, San Jose, California PUBLICATIONS Martin, D.L., M. Olin. 1992. The decline of the Yosemite toad & the role of the modern zoo. Maagizo, 29(7):8-9. Martin, D.L. 1992. Sierra Nevada Anuran Guide. Canorus Ltd. Press, San Jose, CA. Pp 28. Lawson, R., P.G. Frank and D.L. Martin. 1990. A gecko new to the United States herpetofauna with notes on other gekkonids inhabiting the Florida Keys. Herpetological Review, 22(1):11-12. vii Martin, D.L. 1990. Captive husbandry as a technique to save a species of special concern, the Yosemite toad (Bufo canorus). In R.E. Staub (ed.), Proceedings of the Fifth Conference on the Captive Propagation and Husbandry of Reptiles and Amphibians, pp 16-32. Northern California Herpetological Society, Special Publication No. 6. AWARDS U.S. Department of Justice Certificate of Commendation, for outstanding performance and invaluable assistance in support of the activities of the Environment and Natural Resources Division, Washington DC, 2003 Marianna Pisano Memorial Scholarship, for the most outstanding Biological Science student, San Jose State University, San Jose, California, 1991 FIELDS OF STUDY Major Field: Conservation Biology Studies in Theoretical Ecology with Professor Samuel S. Sweet Studies in Evolutionary Biology with Professor John A. Endler viii ABSTRACT Decline, Movement and Habitat Utilization of the Yosemite Toad (Bufo canorus): An Endangered Anuran Endemic to the Sierra Nevada of California by David Lamar Martin Since 1990 there has been an accumulation of evidence suggesting that global amphibian populations have declined. The majority of these declines can be explained by habitat destruction, but some have occurred in seemingly “pristine” habitats such as the high elevation Sierra Nevada mountains of California where the Yosemite toad (Bufo canorus), which is endemic to these “pristine” habitats in the Sierra, has declined. Unfortunately, the designation of “pristine” habitat is based on general management goals rather than on the habitat utilized by amphibians. This study used radio transmitters to track the movements of toads to determine what habitats are utilized and found that adult B. canorus are capable of traveling up to 657m ( x = 278m) from breeding pools to upland foraging habitats, thereby providing a mean total home range estimate for adult B. canorus of 8,457m2, which is considerably larger than previously suggested. Further, this study found that B. canorus conducts much of its movements at night and is therefore not strictly diurnal as previously reported. The habitat utilized by B. canorus was found to include meadows, which were used predominantly by subadult toads and matched the reported preferred habitat of lush meadows with willows and a mean vegetation height of 25cm; upland foraging habitat, which is predominantly occupied by adults and is characterized by rocky substrate and lush vegetation dominated by lupines ix occurring on mountain slopes with a mean vegetation height of 11cm; and overwintering habitat, which is characterized by a gravel and duff substrate that occurs on the margins of old forest with a mean vegetation height of 3cm.