Thesis
Black bear density in the central Cascades, Washington
Washington State University
Master of Science (MS), Washington State University
2015
Handle:
https://hdl.handle.net/2376/102480
Abstract
Population estimates of black bears are often used by agencies to set and monitor management objectives such as providing hunting opportunities and minimizing human-bear conflict, however, common methods to estimate population parameters may provide misleading interpretations. In Washington State, the black bear population is managed using density estimates extrapolated from home range data from the literature and is estimated to be 39 bears/100 km2 in western Washington and 18 bears/100 km2 in eastern Washington. However, recent home range estimates from within Washington suggest that home ranges may be larger than expected, with unknown effects on density and harvest rates. From 2013-2014, we investigated the density and home range of black bears in the Snoqualmie area of western Washington and Lake Wenatchee in eastern Washington using DNA mark-recapture data and information from radiocollared bears. Density was estimated using spatially explicit capture-recapture models and closed population models that incorporate telemetry information. Both density methods produced similar results within and between study areas. After excluding cubs from density estimates, density in Snoqualmie was approximately half of what had been previously predicted (18 bears/100 km2), and in Lake Wenatchee, density was higher than anticipated using home range data and averaged 24 bears/100 km2. Similarly, home range estimates were twice as large as those used for population estimates in Washington and did not differ between study area (female: p = 0.97, male: p = 0.46). We recommend that western Washington and the east slopes of the Cascade Mountains be managed at approximately 20 bears/100 km2 to maintain sustainable harvest rates. Further investigation is warranted to estimate density in the more xeric environments in eastern Washington.
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Details
- Title
- Black bear density in the central Cascades, Washington
- Creators
- Lindsay Suzanne Welfelt
- Contributors
- Robert B. Wielgus (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Agricultural, Human, and Natural Resource Sciences, College of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900524869201842
- Language
- English
- Resource Type
- Thesis