University of Montana ScholarWorks at University of Montana Graduate Student Theses, Dissertations, & Professional Papers Graduate School 2010 Are black bears declining in Montana? Inference from multiple data sources in the face of uncertainty Julie Ann Beston The University of Montana Follow this and additional works at: https://scholarworks.umt.edu/etd Let us know how access to this document benefits ou.y Recommended Citation Beston, Julie Ann, "Are black bears declining in Montana? Inference from multiple data sources in the face of uncertainty" (2010). Graduate Student Theses, Dissertations, & Professional Papers. 53. https://scholarworks.umt.edu/etd/53 This Dissertation is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. ARE BLACK BEARS DECLINING IN MONTANA? INFERENCE FROM MULTIPLE DATA SOURCES IN THE FACE OF UNCERTAINTY By JULIE ANN BESTON B.S. in Biology and Mathematics, Truman State University, 2005 Dissertation presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Fish and Wildlife Biology The University of Montana Missoula, MT Fall 2010 Approved by: Perry Brown, Associate Provost for Graduate Education Graduate School Elizabeth Crone, Chair Wildlife Biology Vanessa Ezenwa Division of Biological Sciences Mark Hebblewhite Wildlife Biology Scott Mills Wildlife Biology Michael Mitchell Montana Cooperative Wildlife Research Unit Beston, Julie, Ph.D., Fall 2010 Fish and Wildlife Biology Are black bears declining in Montana? Inference from multiple data sets in the face of uncertainty Chairperson: Dr. Elizabeth Crone Carnivores are managed both to maintain populations and reduce conflict with humans, but data-based decision-making is difficult due to the expense of data collection. When new fieldwork is impossible, we can benefit from available data in assessing populations. I used demographic and harvest data to assess the population status of black bears (Ursus americanus) in Montana. I conducted a hierarchical Bayesian meta-analysis of black bear demographic studies to evaluate geographic structuring and estimate vital rates and population growth rate. Adult survival is higher in the west than the east, but the reverse is true for fecundity. The mean population growth rate is 0.97 (0.93, 1.00) in the west, but variability among populations suggests many are increasing. I analyzed the sex and age of bears harvested in Montana, 1985-2005, to estimate harvest rate and population size. The harvest rate of females is 4.3% and the total population is 30- 40000. Montana’s population is stable or increasing. I modeled discrete and continuous spatial variation in population growth rate with varying movement and habitat distributions. In order for the entire population to be stable, fewer than 20% of individuals can disperse, which is reasonable based on the literature. Landscapes with 20-30% source habitat were generally able to sustain populations. I applied a similar approach to brown bears (U. arctos) in British Columbia, where management of salmon and bears occur independently despite the reliance of brown bears on salmon. I conducted a demographic meta-analysis and used several models and parameter combinations to evaluate the consequences of salmon reduction and bear harvest. While both affect populations, bear harvest has a more dramatic effect. My research highlights the application of available data when new fieldwork is not feasible. Both intensive, demographic data and extensive data, like statewide harvest information, are useful in evaluating population status and management actions. ii ACKNOWLEDGEMENTS First and foremost, I would like to thank everyone at the University of Montana who made this work possible. Elizabeth Crone is a great advisor, and without her commitment, I could not have succeeded. Jeanne Franz is an invaluable asset to the Wildlife Program who always had the answers or could direct me to someone who did. My committee; Scott Mills, Mark Hebblewhite, Vanessa Ezenwa, and Mike Mitchell; were generous, both with criticism and support, and improved my ability as a scientist. Mike Mitchell, in particular, helped me land this great project and facilitated communication with the powers that be who were interested in my work. Thanks also go to various funding sources. Elizabeth, the College of Forestry and Conservation, and the Wildlife Program, largely thanks to Dan Pletcher, were essential in keeping me fed and working. Rick Mace and Montana Fish, Wildlife, and Parks provided guidance, data, and funding for my work on black bears. M. Sanjayan gave me the opportunity to get paid working on some vastly different questions with the Nature Conservancy and also introduced me to Richard Geo, who was my connection for the final chapter of my dissertation on grizzly bears. I also received support through the National Science Foundation’s EPSCoR program. Many individuals and agencies provided information for the analysis in chapter 2, including: T. Berens, Northwest Territories Environment and Natural Resources; W. Bolduc, R. Cross and J. Vashon, Maine Department of Inland Fisheries & Wildlife; K. Bunnell, Utah Division of Wildlife Resources; K. Burguess, New Jersey Division of Fish and Wildlife; J. Cardoza, Massachusetts Division of Fisheries & Wildlife; K. Cartwright, Arkansas Game and Fish Commission; H. Hristienko, Manitoba Conservation; H. Jolicoeur, Québec Ministère des Ressources Naturelles et de la Faune; E. Kowal, Saskatchewan iii Environment & Resource; R. Mace, Montana Fish, Wildlife, & Parks; G. MacHutchon, Wildlife Biology Consultant, British Columbia; P. Murphy, New Brunswick Department of Natural Resources; M. Obbard, Ontario Ministry of Natural Resources; L. Olver, Wisconsin Department of Natural Resources; C. Ryan, West Virginia Division of Natural Resources; H. Spiker, Maryland Department of Natural Resources; S. Still, South Carolina Department of Natural Resources; A. Timmins, New Hampshire Fish and Game Department; R. Winslow, New Mexico Department of Game and Fish; P. Zager, Idaho Department of Fish and Game. Thanks also to the many biologists and field technicians who collected those data. Finally, the unwavering support and encouragement of my family helped pull me through the hard times and keep me focused on the light at the end of the tunnel. My husband, Adam, and my daughter, Journey, gave me the motivation to keep working toward the future that we envision together. My parents, Mike and Diana Bates, my sister, Amanda Stephens, and my awesome niece, Wendy, were the best cheerleaders anyone could wish for. This dissertation is really for all of them. iv TABLE OF CONTENTS ABSTRACT .................................................................................................................... ii ACKNOWLEDGEMENTS ........................................................................................... iii LIST OF TABLES ....................................................................................................... vii LIST OF FIGURES .................................................................................................... viii CHAPTER 1 – Introduction and overview .................................................................... 1 CHAPTER 2 – Variation in life history and demography of the American black bear (Ursus americanus) ................................................................................................................... 6 Abstract … ................................................................................................................. 6 Introduction ............................................................................................................... 7 Methods…… ............................................................................................................ 10 Results..... ................................................................................................................ 14 Discussion.... ............................................................................................................ 16 CHAPTER 3 – What do harvest data tell us about American black bears? .............. 38 Abstract …... ............................................................................................................ 38 Introduction ............................................................................................................. 39 Methods …............................................................................................................... 43 Estimating harvest rate....................................................................................... 43 Using harvest to detect declines .......................................................................... 47 Results …... ............................................................................................................. 48 Estimating harvest rate....................................................................................... 48 Using harvest to detect declines .......................................................................... 50 Discussion ............................................................................................................... 50 v CHAPTER 4 – Spatial