Doctoral Dissertations

Date of Award

5-2002

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Ecology and Evolutionary Biology

Major Professor

Michael R. Pelton

Abstract

To assess the impact of perceived poaching on black bears (Ursus americanus) within Great Smoky Mountains National Park (GSMNP), I used 31 years (1968 - 1998) of data to compare population characteristics between 2 study areas. I incorporated 1,015 captures of 705 bears into 4 models to estimate population abundance. I calculated density by delineating an effective study area as the region defined by circumscribing all trapsites with the average summer home range radius of bears in GSMNP. Mean density estimates ranged from 0.73 to 1.63 bears/km2 on the North Carolina study area (NCSA) and from 0.65 to 1. 77 bears/km2 on the Tennessee study area (TNSA). I compared sex ratios, age structures, body sizes, litter sizes, female survival rates, and densities between the NCSA and TNSA. Density, as estimated by back dating, was the only parameter that differed, averaging approximately 25% lower on the NCSA. I determined that habitat quality driven by differences in white oak prevalence, not poaching, most likely explained the higher density of bears on the TNSA compared to the NCSA. Bait-station indices reflected the lower density of bears on the NCSA and correlated significantly with back dating estimates. Male bears traveled greater distances between captures than females and young bears delayed dispersal until 2.5 - 3.5 years of age. Although males moved long distances more frequently than females, few individuals dispersed. These movement patterns indicated that colonization of lost range would be slow and unlikely across large areas of unsuitable habitat. Weights and morphometrics of bears fluctuated through time, but did not exhibit a clear pattern relative to fall hard mast availability. Bears seemed able to exploit soft mast and other food sources to ameliorate low hard mast production, but still were affected by overall food availability. Densities increased during years of adequate food supply to levels exceeding 1.0 bear/km2, and then declined sharply after mast failures. During this study, such declines were followed by synchronized breeding, prolific cub production, and rapid population rebounds. Future management and research efforts should account for the impact of periodic food shortages on population ecology of bears in GSMNP.

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