Year of Publication

2016

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Agriculture, Food and Environment

Department

Animal and Food Sciences

First Advisor

Dr. John J. Cox

Second Advisor

Dr. Michael J. Lacki

Abstract

Reintroduced populations are vulnerable to demographic and environmental stochasticity, deleterious genetic effects, and reduced population fitness, all of which can increase extinction probability. Population viability is principle to determining the status of reintroduced populations and for guiding management decisions. To attempt to reestablish black bear (Ursus americanus) populations in the central Appalachians, two reintroductions using small founder groups occurred during the 1990s in the Big South Fork area along the Kentucky-Tennessee border (BSF) and in the Jefferson National Forest along the Kentucky-Virginia border (KVP). My objectives were to estimate demographic and genetic parameters, and to evaluate long-term viability and reintroduction success for the KVP and BSF black bear populations.

The KVP grew rapidly to 482 (317–751) bears with a significantly female-biased sex ratio by 2013. Spatially explicit capture-recapture models suggested KVP recolonization may continue to the southwest and northeast along linear mountain ridges. Based on radio-monitoring during 2010–2014, high adult female survival and moderate mean litter sizes were estimated in both populations. All mortality was anthropogenic and males were 4.13 times more likely to die than females. Two-cub litters were most probable in the BSF, whereas the KVP had similar probabilities of two- and three-cub litters. The average annual mortality that occurred during the study period was sustainable and allowed for moderate growth (λKVP = 1.10; λBSF = 1.13). Continued mortality at the higher 2015 rate, however, resulted in probabilities of ≥25% population decline over 10 years of 0.52–0.53 and 0.97–0.98 in the KVP and BSF, respectively.

Rapid population growth during the 13–17 years post-reintroduction and the overlapping generations inherent to bears retained genetic diversity. Cumulative findings indicated both reintroductions were successful at establishing viable, self-sustaining populations over the long-term. The anthropogenic mortality rate during 2015, if sustained, could cause precipitous declines in these populations. Reimplementation of annual vital rate monitoring and conservative harvests should be considered. Connectivity may be established between these two reintroduced black bear populations if growth and recolonization continue.

Digital Object Identifier (DOI)

http://dx.doi.org/10.13023/ETD.2016.076

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