Doctoral Dissertations

Date of Award

12-1999

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Human Ecology

Major Professor

Michael R. Pelton

Committee Members

Ralph W. Dimmick, Clifford C. Amundsen, Gary F. McCracken

Abstract

The Louisiana black bear (Ursus americanus luteolus)once was common throughout east Texas, Louisiana, and southern Mississippi. By the mid-1980's, extensive habitat destruction reduced its range by >80%, and long-term survival of the subspecies is now uncertain,was the pioneer investigation of the population status andResults were used by the U.S.This study ecology of D. a. luteolus.Fish and Wildlife Service (USFWS) to address a petition to list the subspecies as federally endangered, and provided the basis for management recommendations intended to promote population recovery. Investigations were conducted from 1988-1991 in the Tensas River Basin of northeasternLouisiana, 1 of only 2 extant population centers for U. a.luteolus. One study area (Deltic) consisted of small (<8-<1100 ha), fragmented, insular tracts of bottomland hardwoods separated by larger expanses of agricultural lands. The other area (Tensas) included a more contiguous,yet also insular, bottomland hardwood forest (>396 km2) on public and private lands that comprised the largest remnant forest in the Tensas River Basin.Twenty-five bears (13 F, 12 M) were trapped and radio monitored to document occurrence, morphology,population characteristics, movements, denning, and foodAdults comprised 64% of the trapped sample,females ranged in weight from 56.7-128.8 kg ( x̄ 73 kg);habits. Adult adult males ranged from 103.9-181.1 kg ( x̄ 137 kg). Body Weights of Tensas River Basin bears were among the heaviest reported for the southeastern coastal plain. At least 16 cubs (9 Deltic, 7 Tensas) were born during the study.Minimum mean litter size was 2.25 on Deltic (n = 4), and1.8 on Tensas (n = 5). No mortality of radio collared bears was recorded on Deltic, but 5 of 14 radio collared Tensasbears died from either documented or suspected illegal kill. Estimated annual survival rate for radio collared adult females on Tensas was 90.5% (95% Cl = 0.74-1.0).Minimum population estimates (bears ^1.5 years old), based on trapping and observation, were 29 bears on Deltic(1/1.27 km2) and 48 on Tensas (1/8.34 km2) .Mean size of home ranges, estimated by 100% AdaptiveKernel, 100% Harmonic Mean, and 100% Minimum Convex Polygon Methods, were 13.5, 10.8, and 6.7 km2, respectively, forDeltic females (n = 6), and 148.4, 98.0, and 86.2 km2 forCorresponding mean ranges for Tensas Females (n = 5) were 41.9, 52.9, and 24.3 km2, respectively,Deltic males (n = 3).and for Tensas males (n = 3) were 329.4, 248.3, and 144.6km2. Total and seasonal home ranges of males were largerthan females (P < 0.05). Adults had larger total ranges than non-adults (P < 0.05). Ranges of Tensas bears were larger than Deltic bears (P < 0.05).range overlap was considerable. Fewer female ranges overlapped on Tensas compared to those on Deltic, but the Male-female home degree of overlap was greater on Tensas. Mos^^ (97%)daytime locations were in forested habitat. Bears usedwooded habitat linkages as travel corridors to traverseagricultural lands. They also used linkages for feeding,bedding, and denning. No bear movements between Deltic andTensas were noted. The only record of dispersal was a subadult male from Tensas that was recovered dead >1 year later in Claiborne County, Mississippi, approximately 64 km from his capture site.Denning activities of 20 bears (12 F, 8 M) were studied for a total of 30 den-years (19 F, 11 M). Pregnant Females (n=8) entered dens earlier (P < 0.001), emerged later (P < 0.001) and denned longer (P < 0.001) than all other bears. Mean denning length for pregnant females was142 days. Their median den entrance was 3 December (range=26 November-12 December); median emergence was 24 April(range = 6 April-30 May). Adults (n = 21) denned longer (P= 0.023) than subadults (n = 7). At least 13 denning bearsused >1 den site during a season. Eleven bears displayed some winter activity. Bears used elevated cavities in baldcypress (Taxodium distichum) and overcup oak (Quercus Lyrata), ground nests, and brush piles for winter dens.Tree dens were used by 13 out of 20 bears, including 9 of12 adult females. Only 1 bear, an adult male on Tensas,reused a den (bald cypress). Bears in tree dens dennedlonger (P < 0.001) than those in ground dens.Food habits of bears were inferred through observations of feeding sign and scat analysis. The most frequently occurring food items in 164 scats were beetles (30%), corn(29%), acorns (28%), and vegetation (18%). In 104 (64%)scats, 1 food item comprised s:96% of the volume. Of these cats, 72% were composed of only 1 item including acorns,soft mast, grass and sedge seeds, vegetation, and crops.Recommendations were proposed for management of black bear habitat within the range of U. a. luteolus, and elsewhere in the southeastern coastal plain. Guidelines Centered on the use of active forest management to provide a mosaic of various habitat conditions, including early successional and old-growth habitats, sufficient to provide abundance, diversity, and stability of: foods, dens and denning sites, and escape cover. Conservation, management,and creation of habitat linkages among disjunct forestedtracts, and reforestation of open lands to provide additional habitat also were recommended. Management of human access into bear habitat and the corresponding impacts on bear populations were discussed. Development of a public conservation ethic concerning bears, and establishment of partnerships for bear management and restoration were identified as important to bear recovery efforts.

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