Theses and Dissertations
ORCID
https://orcid.org/0009-0009-4024-8063
Advisor
Morin, Dana J.
Committee Member
Evans, Kristine O.
Committee Member
Granger, Joshua J.
Committee Member
Flaherty, Elizabeth A.
Date of Degree
12-12-2025
Original embargo terms
Immediate Worldwide Access
Document Type
Dissertation - Open Access
Major
Forest Resources (Wildlife, Fisheries and Aquaculture)
Degree Name
Doctor of Philosophy (Ph.D.)
College
College of Forest Resources
Department
Department of Wildlife, Fisheries and Aquaculture
Abstract
American black bears (Ursus americanus) once ranged widely across the United States, but habitat loss and overexploitation in the early 20th century caused dramatic declines and extirpations across much of their range. Legal protections, translocations, and forest restoration have since promoted recovery, and black bears are now recolonizing portions of their historical range, including Mississippi. Effective conservation requires understanding the factors that shape recolonization. In this dissertation, I examined genetic connectivity, isotopic niche breadth, and habitat use to assess how black bears are re-establishing in Mississippi. In Chapter 1, I investigated genetic structure and connectivity of bears in western Mississippi using microsatellite genotyping. I identified three distinct genetic clusters corresponding to the Tensas River Basin, Upper Atchafalaya River Basin, and Arkansas subpopulations. Most gene flow originated from Tensas River Basin, but ancestry patterns indicated that southern Mississippi primarily received migrants from Upper Atchafalaya. Genetic diversity was greatest in southern Mississippi. These findings show that recolonization is occurring through multiple routes and highlight the importance of maintaining and enhancing habitat connectivity. In Chapter 2, I used stable isotope analysis of hair samples and food items to evaluate dietary niche breadth by region and sex. Males had broader isotopic niches than females, consistent with their larger home ranges and more varied foraging. Niche sizes were similar between the Delta and southwestern Mississippi, suggesting that reforestation in the Delta provides foraging opportunities comparable to intact forests in the southwest. In Chapter 3, I applied occupancy modeling to hair snare detections to assess summer site use in relation to forest stand and landscape characteristics. Bears were more likely to use landscapes with greater forest cover, larger patches, and more linear connectivity, such as riparian corridors. At the stand scale, use increased with more understory soft mast and fewer midstory shade-intermediate trees. A predictive map showed most use in contiguous forests of the southwest and localized hotspots in the Delta. Together, these results demonstrate that bottomland hardwood reforestation is supporting black bear recolonization in Mississippi and underscore the need to continue expanding and connecting forests to sustain recovery.
Sponsorship (Optional)
National Fish and Wildlife Foundation (1907.20.067326), American Philosophical Society Lewis and Clark Fund grant, Arkansas Game and Fish Commission, Forest and Wildlife Research Center at Mississippi State University, based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, McIntire-Stennis project under accession numbers 1020959 and 7008167
Recommended Citation
Todt, Lacy Ann Dolan, "Recolonizing black bears (Ursus americanus) in Mississippi: Gene flow, isotopic niche, and habitat use" (2025). Theses and Dissertations. 6800.
https://scholarsjunction.msstate.edu/td/6800
