Year of Award

2009

Document Type

Thesis

Degree Type

Master of Science (MS)

Degree Name

Wildlife Biology

Department or School/College

College of Forestry and Conservation

Committee Chair

Mike Mitchell

Commitee Members

Kerry Foresman, Mike Schwartz, Pete Zager, Scott Mills

Keywords

black bear, food productivity, Idaho, mark-recapture, monitoring, noninvasive genetic sampling, population dynamics, population genetics, Ursus americanus, Wahlund effect

Abstract

I conducted research on the demography of a harvested north Idaho black bear (Ursus americanus) population to determine the underlying dynamics of changes in population abundance, to determine how much these dynamics were driven by variation in food productivity, and to evaluate how these processes could influence inferences based on mark-recapture analysis. In cooperation with Idaho Department of Fish and Game and the USDA Forest Service, I used barb-wire corrals to collect black bear DNA during 2003-2006 in the Purcell Mountains of Idaho. We analyzed these DNA samples to determine the number of uniquely identified individuals in each year, Nu. I used a combination of both genetic and mark-recapture analyses to evaluate the sources of variation in Nu over the four years and to what extent this variation was driven by changes in productivity of foods on the landscape. Specifically, I investigated deviations of Hardy-Weinberg equilibrium and genetic substructure in relation to changes in abundance, and whether variation in vital rates were a function of changing berry productivity in the study area. I found a heterozygote deficiency and detected genetic substructure indicating I sampled ≤ 4 subpopulations within the same area over the four years (a Wahlund Effect). My mark-recapture analyses suggest this pattern was probably in response to landscape changes in summer berry abundance. My results suggest important variation in population dynamics driven by changes in food productivity, which should be considered when using mark-recapture analyses to monitor population trends for black bears.

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© Copyright 2009 Barbara McCall