Population dynamics and management of brown bears on Kodiak Island, Alaska


Van Daele, Lawrence J.. (2007). Population dynamics and management of brown bears on Kodiak Island, Alaska. Theses and Dissertations Collection, University of Idaho Library Digital Collections.

Population dynamics and management of brown bears on Kodiak Island, Alaska
Van Daele, Lawrence J.
Brown bear--Population viability analysis--Alaska--Kodiak Island Bear hunting--Alaska--Kodiak Island
Natural Resources
Brown bear (Ursus arctos) populations along the North Pacific Rim are generally healthy and an important economic resource, yet there are few long-term studies of their population dynamics and harvest management. This project gathered information on the population dynamics of bears on Kodiak Island, Alaska to develop an easily understood model for use by managers to develop harvest strategies and guidelines.;I investigated a geographically closed brown bear population with no impassable physical barriers from 1982-2004. I hypothesized that Kodiak had a single bear population that could occupy any habitat and would use the best resources available. I investigated 402 marked bears within 4 diverse study areas, including 261 that were radiocollared, yielding 15,539 relocations. Mean home ranges for females were significantly smaller than males, and varied between areas. There was considerable home range overlap and no evidence of territoriality. Topography, vegetation, and salmon availability varied between areas, as did denning habitat and chronology. Elevations used by bears varied by area, reproductive status, and season. Most variations appeared to be related to resource availability. Reproductive fitness and bear densities were comparable in all areas.;Generations of behavioral specialization have resulted in a population that is a radiating continuum in which bears that lived adjacent to each other used similar resources, but those living apart used different resources. Mitochondrial DNA analysis confirmed the hypothesis that bears on Kodiak were a single population; however resource use patterns rejected the hypothesis that all bears used the same "optimal" habitat. This ecological flexibility resulted in a higher carrying capacity than if all bears conformed to uniform habitat use patterns.;I created a model that used population and harvest inputs to derive estimates of population change and the number of trophy-sized bears. Model validation suggested the Kodiak bear population was healthy and productive as it supported a sustainable harvest that yielded consistently large bears. To obtain refined harvest strategies, managers must consider local population parameters, management objectives, harvest characteristics, and confidence levels. There is no single harvest rate that is applicable to all situations.
Thesis (Ph. D., Natural Resources)--University of Idaho, February 2007.
Major Professor:
Edward O. Garton.
Defense Date:
February 2007.
Format Original:
122 leaves :col. ill., col. maps ;29 cm.

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