Dissertation
NUTRITIONAL AND LANDSCAPE ECOLOGY OF BROWN BEARS (URSUS ARCTOS)
Doctor of Philosophy (PhD), Washington State University
01/2020
Handle:
https://hdl.handle.net/2376/116975
Abstract
The manuscripts within this dissertation relate to the nutritional and landscape ecology of brown bears (Usus arctos) within Katmai National Park, Alaska and elsewhere. In chapter one we examined the role of marine-influenced resources (e.g., salt marsh and intertidal areas) on the diet and habitat selection of coastal brown bears in Katmai National Park, seeking to understand how changes to the marine environment might affect bears in coastal ecosystems. We found that the proportion of salmon in the diets of coastal bears has declined by 55% and the number of bears has declined by 64% since the 1990s. Chum and pink salmon abundance in coastal streams has declined while human visitation has increased by 1000% during that time. In chapter two we investigated the use of salt marshes by bears in Katmai National Park, compared the nutritional content of salt marshes to other vegetation, and examined how the proportional contribution of vegetation to bear diets affects proxies of productivity (mass and fat). Densities of bears on salt marshes were higher than most coastal salmon streams and up to 43 times higher than the average density of bears throughout the park. Female bears gained mass (29 + 17 kg, n= 20), 90% gained lean mass (22 + 19 kg, n= 17), and 74% gained fat (8 + 13 kg, n= 14) on plant matter, suggesting plant matter, including salt marsh vegetation, can be valuable for bear conservation. In chapter three we conducted feeding trials with captive bears at Washington State University to aid in the more accurate estimation of diets of wild bears. We fed bears controlled diets from March 21 (den emergence) to October 30 2019 (den entry) and measured growth patterns of guard hairs and underfur, the timing of shedding, isotopic incorporation rates of 15N and 13C in blood and hair, and isotopic discrimination values for blood and hair. We found that guard hair had non-constant rates of growth and that isotopic discrimination for bears was high and variable between tissues and diets when compared to other studies.
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Details
- Title
- NUTRITIONAL AND LANDSCAPE ECOLOGY OF BROWN BEARS (URSUS ARCTOS)
- Creators
- Joy Anne Erlenbach
- Contributors
- Charles T Robbins (Advisor)Lisa Shipley (Committee Member)Grant Hilderbrand (Committee Member)Caren Goldberg (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 155
- Identifiers
- 99900581812601842
- Language
- English
- Resource Type
- Dissertation