Date of Award
Master of Science (MS)
Wildlife and Fisheries Biology
Dr. David Jachowski, Committee Chair
Dr. Patrick Jodice, Committee Co-Chair
Dr. Yoichiro Kanno
Black bears (Ursus americanus) are managed as a game species in the northwestern region of South Carolina. However, no formal research study has examined their long-term population trends. I used the Downing harvest population reconstruction technique to establish abundance trends. The total population in 2013 was estimated at about 412 bears, increasing from about 97 bears in 1998. I also derived abundance, density, average age, and sex ratios at a county-level to investigate differential stages of recovery. Overall my results suggest that in 1998-2013 Oconee county had a rapidly expanding population, Pickens county requires further investigation into potential bear overharvest, and the Greenville county population is dispersing from Wildlife Management Areas to private lands. My findings suggest that further research into predictive models to determine the maximum sustainable harvest rate for this population and quantify management decisions is needed.
I also analyzed black bear capture-recapture data collected by the South Carolina Department of Natural Resources (SCDNR) using hair snares in 2013-2014, to estimate density. I compared results from non-spatial and spatially explicit models. Black bear density estimated from non-spatial models was 0.187 bears/km2 (SE=0.071 bears/km2) in 2013 and 0.156 bears/km2 (SE=0.056 bears/km2) in 2014. Density estimated from spatially explicit models was 0.168 bears/km2 (SE=0.024 bears/km2) in 2013 and 0.177 bears/km2 (SE=0.023 bears/km2) in 2014. Non-spatial methods showed greater variance between models, and suggest violation of geographic closure assumptions. Overall I recommend that spatial models be used in future capture-recapture surveys to establish density and sex ratios.
Finally, I undertook a preliminary investigation into the usefulness of acorn mast, human-bear interactions, and bait station visitation indices collected by the SCDNR. I found that the quality of white, red, and chestnut oak acorn crops significantly predicted black bear population growth rates (λ). My results also suggested that bears avoid the human-dominated landscape in plentiful acorn years. Bait station indices did not significantly predict λ, and I recommend a focused study into the viability of increasing resources to improve the statistical power of these surveys.
Azad, Shefali, "Population Dynamics of Black Bears in Northwestern South Carolina" (2016). All Theses. 2592.