The University of Maine DigitalCommons@UMaine Electronic Theses and Dissertations Fogler Library 12-2003 Pond-Breeding Amphibian Species Distributions in a Beaver-Modified Landscape, Acadia National Park, Mount Desert Island, Maine Jesse Cunningham Follow this and additional works at: http://digitalcommons.library.umaine.edu/etd Part of the Fresh Water Studies Commons, and the Natural Resources and Conservation Commons Recommended Citation Cunningham, Jesse, "Pond-Breeding Amphibian Species Distributions in a Beaver-Modified Landscape, Acadia National Park, Mount Desert Island, Maine" (2003). Electronic Theses and Dissertations. 384. http://digitalcommons.library.umaine.edu/etd/384 This Open-Access Thesis is brought to you for free and open access by DigitalCommons@UMaine. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of DigitalCommons@UMaine. POND-BREEDING AMPHIBIAN SPECIES DISTRIBUTIONS IN A BEAVER-MODIFIED LANDSCAPE, ACADIA NATIONAL PARK, MOUNT DESERT ISLAND, MAINE BY Jesse Cunningham B.A. Middlebury College, 1995 A THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science (in Ecology and Environmental Sciences) The Graduate School The University of Maine December, 2003 Advisory Committee: Aram J.K. Calhoun, Assistant Professor of Wetland Ecology, Co-Advisor William E. Glanz, Associate Professor of Zoology, Co-Advisor Cynthia S. Loftin, Assistant Professor of Wildlife Ecology POND-BREEDING AMPHIBIAN SPECIES DISTRIBUTIONS IN A BEAVER-MODIFIED LANDSCAPE, ACADIA NATIONAL PARK, MOUNT DESERT ISLAND, MAINE By Jesse Cunningham Thesis Co-Advisors: Dr. Aram J.K. Calhoun and Dr. William E. Glanz An Abstract of the Thesis Presented in Partial Fulfillment of the Requirements for the Degree of Master of Science (in Ecology and Environmental Sciences) December, 2003 In order to maintain pond-breeding amphibian species richness, it is important to understand how both natural and anthropogenic disturbances affect species assemblages and individual species distributions both at the scale of individual ponds and at a larger landscape scale. The goal of this project was to investigate what characteristics of ponds and the surrounding wetland landscape were most effective in predicting pond-breeding species richness and the individual occurrence of wood frog (Rana sylvatica), bullfrog (Rana catesbeiana) and pickerel frog (Rana palustris) breeding sites in a beaver- modified landscape and how this landscape has changed over time. The wetland landscape of Acadia National Park was historically modified by the natural disturbance cycles of beaver (Castor- ca~zadensis),and since their reintroduction to the island in 192 1, beaver have played a large role in creating and maintaining palustrine wetlands. In 2000 and 200 1, I studied pond-breeding amphibian assemblages at 7 1 palustrine wetlands in Acadia National Park, Mount Desert Island, Maine. I determined breeding presence of 7 amphibian species and quantified 15 variables describing local pond conditions and characteristics of the wetland landscape. I developed a pr-iori models to predict sites with high amphibian species and used model selection with Akaike's Information Criterion (AIC) to identify important variables. Single species models were also developed to predict wood frog, bullfrog and pickerel frogs breeding presence. The variables for wetland connectivity by stream corridors and the presence of beaver disturbance were the most effective variables to predict sites with high amphibian richness. Wood frog breeding was best predicted by local scale variables describing temporary, fishless wetlands and the absence of active beaver disturbance. Abandoned beaver sites provided wood frog breeding habitat (70%) in a similar proportion to that found in non-beaver- influenced sites (79%). In contrast, bullfrog breeding presence was limited to active beaver wetlands with fish and permanent water, and 80% of breeding sites were large (>2ha in size). Pickerel frog breeding site selection was predicted best by the connectivity of sites in the landscape by stream corridors. Models including the presence of beaver disturbance, greater wetland perimeter and greater depth were included in the confidence set of pickerel frog models but showed considerably less support. Analysis of historic aerial photographs showed an 89% increase in the total number of ponded wetlands available in the landscape between the years of 1944 and 1997. Beaver colonization generally converted forested wetlands and riparian areas to open water and emergent wetlands. Temporal colonization of beaver wetlands favored large sites low in the watersheds and sites that were impounded later were generally smaller, higher in the watershed, and more likely to be abandoned. These results suggest that beaver have not only increased the number of available breeding sites in the landscape for pond-breeding amphibians, but the resulting mosaic of active and abandoned beaver wetlands also provides suitable breeding habitat for species with differing habitat requirements. ACKNOWLEDGEMENTS The process of conducting research and writing a thesis is not solely the result of the effort of one person. I would like to acknowledge some of the people who have contributed to my success in this endeavor. Aram Calhoun and Bill Glanz served as my co-advisors. I am indebted to both of them for having faith in me and allowing me the freedom to pursue my research interests with minimal supervision. Freedom is not without its frustrations and they both were available for help when I needed it most. Aram provided unlimited enthusiasm and support for my work and gave me pep talks when I became overwhelmed by the task at hand. Bill added a balanced perspective when plotting the course of my work and could always be counted on for relevant and valuable advice. Cyndy Loftin served on my committee and provided thoughtful insight, suggestions and feedback. The National Park Service and the Biological Sciences and Plant, Soil and Environmental Sciences departments at UMaine provided funding, and the staff of Acadia National Park assisted with logistical support. I would like to thank the entire ANP resource management staff for their assistance and friendliness, with special thanks to Bruce Connery for help and support beyond the call of duty. Mary Beth Kolozsvary and I worked together under the same grant and shared resources; her understanding of the system in which we worked yielded crucial feedback and countless discussions with her helped me to focus my work. T. Blackburn, R. Chalmers, J. Crocker, J. Everett, T. Hartke, H. Moore, C. Rabatin, E. Taylor, and K. Theriault assisted with field work and Jeff and Wendy Charland shared their home with me and helped to keep me sane during field seasons. My discussions with faculty and other students were invaluable throughout the learning process. I give special thanks to Neal Taylor and Bill Halteman for statistical advice and to the numerous students who I pestered with statistical questions, including Volker Bahn, Rob Baldwin, Mike Bank, and Mike Chadwick. I am indebted to Rob Baldwin for his mentorship, advice and constant encouragement; he would be listed as an honorary committee member if there were such a thing. Last but not least I would like to thank my family, and friends who provided support and distractions, including (but not limited to) Melinda Coleman, Erin Haramoto, Susan Kaspari, Ellen Klinger, Julia Knisel, Josh Laidacker, Keny Lough, T.R. Morley, Jeff Piotrowski, Sultana Shah, Johanna Szillery, and all who shared office space with me in Deering 26. TABLE OF CONTENTS . ACKNOWLEDGEMENTS ................................................................................................11 LIST OF TABLES .............................................................................................................vi .. LIST OF FIGURES ..........................................................................................................vii 1. PREDICTORS OF POND-BREEDING AMPHIBIAN SPECIES OCCURRENCE AND RICHNESS IN A BEAVER-MODIFIED LANDSCAPE ........................................1 Introduction .....................................................................................................................1 Methods ...........................................................................................................................4 Study Area ..................................................................................................................4 Study Species ..............................................................................................................6 Site Selection ..............................................................................................................8 Amphibian Surveys .....................................................................................................9 Site Characterization .................................................................................................11 Data Analysis ............................................................................................................14 Results ...........................................................................................................................18 Amphibian Surveys ...................................................................................................18 Local and Landscape Characteristics ........................................................................22