Masters Theses

Date of Award

8-2004

Degree Type

Thesis

Degree Name

Master of Science

Major

Wildlife and Fisheries Science

Major Professor

Joseph D. Clark

Abstract

Black bears (Ursus americanus) have been extirpated from all but a few areas in southwestern Alabama, and the remaining enclaves are rapidly being lost to development. Adjacent to those remnant bear populations are extensive {>125,000 ha) bottomland hardwood forests in the Mobile-Tensaw Delta {MTD), but bears are nearly absent there. Reintroduction may be possible to reestablish black bears in the MTD and improve the viability of the overall bear population in southwestern Alabama. To determine whether a reintroduction effort is likely to succeed in the MTD, I assessed habitat quality, den site availability, and public support of a restoration effort. To evaluate the habitat quality of the MTD for bears, I compared it with similar alluvial habitats at White River National Wildlife Refuge (White River NWR), where the bear population is high. I then performed a flood simulation using GIS to assess the availability of safe ground dens in the MTD. Finally, I used the Bowman et al. (2004) model based on demographic variables (i.e., age, race, sex) to predict human attitudes towards black bear restoration efforts in the MTD and surrounding areas. I collected data from overstory, midstory, and understory vegetation plots in the MTD and on the North and South management units at White River NWR. Using principal components analysis followed by principal variable selection, I determined that 9 variables associated with 5 principal components (hard mast, soft mast, den tree availability, large tree availability, and total basal area) best explained the variation among the 3 study areas. I detected differences among the study areas for 3 of those principal components (hard mast, soft mast, and den tree availability; t ranged from 2.71 to 5.70, P 􀇢 0.001). Flood simulations for various recurrence levels indicated that nearly all of the MTD floods each year with the only dry locations occurring along the Alabama River. The MTD and surrounding areas showed moderate public support for a black bear reintroduction (range = 25.4-73.8%). Although my study revealed that hard and soft mast production in the MTD was lower than at White River NWR, a previously developed Habitat Suitability Index model and comparisons of hard mast basal area between the MTD (5.39 m2/ha) and Tensas River National Wildlife Refuge (6.98 m2/ha) suggested food resources in the MTD were adequate. A more serious deficiency of the MTD was the almost total lack of suitable den sites, a critical habitat component given the duration and severity of winter flooding there. Flood simulation models indicated that the northern portions of the MTD along the Alabama River were least likely to be inundated and, therefore, were most suitable for ground reintroduction sites. Given that only moderate support for black bear restoration efforts in the MTD was predicted, a strong public relations program will be critical for the reintroduction to be successful. Reintroduction of black bears could be successful in the MTD through the use of artificial denning structures, but long-term population viability will require changes in timber management practices to ensure that adequate tree dens are available.

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