The Louisiana black bear (Ursus americanus luteolus) is comprised of 3 subpopulations, each being small, geographically isolated, and vulnerable to extinction. Hurricanes Katrina and Rita struck the Louisiana and Mississippi coasts in 2005, potentially altering habitat occupied by this federally threatened subspecies. We used data collected on radiotelemetered bears from 1993 to 1995 and pre-hurricane landscape data to develop a habitat model based on the Mahalanobis distance (D²) statistic. We then applied that model to post-hurricane landscape data where the telemetry data were collected (i.e., occupied study area) and where bear range expansion might occur (i.e., unoccupied study area) to quantify habitat loss or gain. The D² model indicated that quality bear habitat was associated with areas of high mastproducing forest density, low water body density, and moderate forest patchiness. Crossvalidation and testing on an independent data set in central Louisiana indicated that prediction and transferability of the model were good. Suitable bear habitat decreased from 348 to 345 km² (0.9%) within the occupied study area and decreased from 34,383 to 33,891 km² (1.4%) in the unoccupied study area following the hurricanes. Our analysis indicated that bear habitat was not significantly degraded by the hurricanes, although changes that could have occurred on a microhabitat level would be more difficult to detect at the resolution we used. We suggest that managers continue to monitor the possible long-term effects of these hurricanes (e.g., vegetation changes from flooding, introduction of toxic chemicals, or water quality changes).
- Volume 23
- Issue 2
- Pages 192-205
- Publication Date 2 November 2012
- DOI 10.2192/ursus-d-11-00032.1
- File Size 520.96 KB
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