Challenges of DNA-based mark-recapture studies of American black bears

Journal of Wildlife Management
By: , and 



We explored whether genetic sampling would be feasible to provide a region-wide population estimate for American black bears (Ursus americanus) in the southern Appalachians, USA. Specifically, we determined whether adequate capture probabilities (p >0.20) and population estimates with a low coefficient of variation (CV <20%) could be achieved given typical agency budget and personnel constraints. We extracted DNA from hair collected from baited barbed-wire enclosures sampled over a 10-week period on 2 study areas: a high-density black bear population in a portion of Great Smoky Mountains National Park and a lower density population on National Forest lands in North Carolina, South Carolina, and Georgia. We identified individual bears by their unique genotypes obtained from 9 microsatellite loci. We sampled 129 and 60 different bears in the National Park and National Forest study areas, respectively, and applied closed mark–recapture models to estimate population abundance. Capture probabilities and precision of the population estimates were acceptable only for sampling scenarios for which we pooled weekly sampling periods. We detected capture heterogeneity biases, probably because of inadequate spatial coverage by the hair-trapping grid. The logistical challenges of establishing and checking a sufficiently high density of hair traps make DNA-based estimates of black bears impractical for the southern Appalachian region. Alternatives are to estimate population size for smaller areas, estimate population growth rates or survival using mark–recapture methods, or use independent marking and recapturing techniques to reduce capture heterogeneity.

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Publication type Article
Publication Subtype Journal Article
Title Challenges of DNA-based mark-recapture studies of American black bears
Series title Journal of Wildlife Management
DOI 10.2193/2006-472
Volume 72
Issue 4
Year Published 2008
Language English
Publisher Wildlife Society
Contributing office(s) Northern Rocky Mountain Science Center
Description 8 p.
First page 1035
Last page 1042
Country United States
State Georgia, North Carolina, South Carolina, Tennessee
Other Geospatial Chattahoochee National Forest, Great Smoky Mountains National Park, Nantahala National Forest, Sumter National Forest
Online Only (Y/N) N
Additional Online Files (Y/N) N
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