Masters Theses

Date of Award

8-2003

Degree Type

Thesis

Degree Name

Master of Science

Major

Wildlife and Fisheries Science

Major Professor

Joseph D. Clark

Committee Members

Frank T. van Manen, David A. Etnier, Sammy L. King

Abstract

Black bear (Ursus americanus) populations in North America have been dramatically reduced as a result of habitat loss, fragmentation, and/or unregulated harvest. The Interior Highlands, the West Gulf Coastal Plain, and the Delta regions of Arkansas once supported large numbers of black bears but, by the early 1900s, bears in the state were limited to a remnant population in the present-day White River National Wildlife Refuge (hereafter "White River"). Bears have since been reestablished in the Interior Highlands of the state and the population in the Delta has grown, but the Gulf Coastal Plain remains uninhabited by a viable bear population. Restoration of bears to the Coastal Plain can provide ecological benefits such as linking isolated bear populations and reestablishing this component of the native ecosystem.

In an attempt to reestablish bears in this region, I used a winter-release technique to translocate 23 adult female black bears with 56 cubs. That technique has been shown to reduce homing of adult female bears. Bears were translocated approximately 160 km from their dens at White River to man-made den structures at Felsenthal National Wildlife Refuge (hereafter "Felsenthal") during spring 2000-2002.

I monitored the fates of all reintroduced bears and evaluated 1-month, 6-month, and 1-year movement parameters of surviving adult females. Total movement of adult female bears the first month post-emergence averaged 43 km. First-month mean daily movements averaged 923 m, and net movement for the first month averaged 27 km. Total movement of surviving adult females 6 months after emergence averaged 223 km; mean daily movement averaged 1,132 m, and net movement during this time averaged 34 km. Total movement of adult females that survived to 1-year post-emergence averaged 311 km. Mean daily movement averaged 782 m, and net movement during the first year averaged 33 km. Average circuity values decreased from 0.47 to 0.14 between 1-month and 6-month intervals, and after 1 year averaged 0.09.

I estimated survival for translocated bears using the Kaplan-Meier staggered entry procedure. Mean first-year post-release survival of adult female bears was 0.587. Cumulative annual survival for all female bears that survived > 1-year post-release was 0.909. Mean annual cub survival of female bears surviving the first year was 0.637.

I conducted cub counts and visited winter dens to monitor the survival of translocated cubs. In all instances, the number of cubs present in winter dens corresponded with the number of cubs observed during fall cub counts. I documented natural reproduction in 2 translocated adult females. This, combined with sightings of unmarked adult male bears, suggests that male bears do not need be translocated to Felsenthal.

Project personnel documented interactions between humans and bears during the study. Over 40 bear sightings were reported from 2000-2002. There was little evidence of nuisance activity, and property damage by translocated bears was minimal.

I used a population model (RISKMAN, version 1.8.006; Ontario Ministry of Natural Resources, Toronto, Ontario, Canada) to estimate population growth and probability of extinction. The model was based on estimates of cub survival; litter survival; subadult male and female survival; adult male and female survival; litter production rate; and the probability of producing 1-, 2-, 3-, or 4-cub litters. I stochastically modeled population growth and extinction rates under various stocking scenarios. With no additional bears translocated to Felsenthal, extinction rates were 22% after 50 years. When I modeled up to 6 annual stockings of 6-12 adult females and 12- 24 cubs, probability of extinction declined by 1- 6%. Relatively high standard errors and yearly environmental variation incorporated into the model, coupled with low first-year survival rates, likely increased extinction probabilities.

I used compositional analysis (Aebischer et al.1993) to evaluate how translocated bears utilized available habitat. Available habitat was determined by the farthest distance traveled by any of the translocated bears. I delineated habitat types for the study area using Multi-Resolution Land Cover data (MRLC; Vogelmann et al. 1998) at a 30- x 30-m cell resolution. Woody wetlands ranked highest among available habitat types at both second- and third-order selection levels. All translocated bears were released in upland pine or mixed forest habitats at Felsenthal to avoid den-site flooding. Nevertheless, bears utilized wetland habitat types more than all other available habitats following den emergence. That trend was detected as bears made early exploratory movements, and became more evident as bears established home ranges within the landscape. Wooded wetlands were more exclusively used when searching for and establishing home ranges, but once established, all forested habitat types within the home range were utilized. The selection of wooded wetlands by translocated bears clearly demonstrates the importance of this habitat type to black bear restoration efforts in the Gulf Coastal Plain.

Lands containing wooded wetlands were influential in home range establishment, and should be managed as potential bear habitat to aid in the restoration process. Also, future land acquisitions should be focused in areas where this potentially limiting habitat type remains.

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