Resource Selection at Different Spatial Scales by Black Bears in Alabama

Abstract

Black bears are native throughout Alabama; however, historic populations have diminished, in part from decreased connectivity and habitat degradation. At present, only two small populations of black bears occur in Alabama. One population is growing quickly in number, while the other is genetically isolated from other black bear populations in the southeastern U.S. Neither population exhibits the spatial growth patterns characteristic of what small populations could achieve. The observed limited spatial growth and genetic isolation could be explained by a lack of corridors, resulting in decreased connectivity, or limited population expansion could be caused by human development and a lack of suitable habitat. Therefore, we created first- and second-order habitat selection models using a Geographic Information System (GIS) for black bears in Alabama in order to understand resource selection at these two spatial scales. The objective of the first-order selection model was to identify potential spatial barriers and areas of population connectivity in Alabama. Models indicated that a lack of available corridors in south Alabama may be limiting gene flow with black bear populations in Florida. Conversely, potential corridors in north Alabama may be facilitating population connectivity and expansion. The objectives of the second-order selection model were to understand how black bears use human dominated landscapes in Alabama and to understand more about the potential for population range expansion despite widespread human presence. We found that much of Alabama has a relatively low potential for population expansion; however, there are areas that could provide opportunities for population growth, allowing bear populations to approach their historic distribution. Understanding potential spatial barriers and population expansion in Alabama could help to inform wildlife managers who are seeking to enhance bear populations and prepare for potential bear population growth in the state and elsewhere in the U.S.