Thesis (M.S.)--University of Idaho, 2007. / Includes bibliographical references. Also available electronically on the Internet.

During 1982-85, population dynamics and denninq ecology of black bears (Ursus americanus) were investigated in Shenandoah National Park, Virginia. Foot snares and culvert traps were used to capture 115 bears a total of 149 times. Radio transmitter collars were fitted to 47 bears. The age structure of the bears captured was indicative of an exploited population. The minimum breeding age of females was 2 years, but 3 years was the modal age. Mean litter size determined by cub counts was 2.0 and females usually bred every second year. Annual mortality rates were estimated at 30% for cubs, 54% for yearlings, 39% for 2-year olds, and 21.5% for older bears. Radio collared adult males had an annual mortality rate of 41.5%, over 5-fold that of adult females (7.5%). Bear density was estimated at 1 bear/0.96-1.49 km'. This high density was explained in part by the difference in male and female mortality rates. The estimated rate of population increase indicated that the population was stable. The most common den types were rock cavities (29 of 61) and above-ground tree cavities (19 of 61). Males did not den in tree cavities. Den sites were not selected for forest type, aspect, or elevation, but ground slope was greater at den sites (P < 0.001) than at random points. Among- and within-year differences in dates of den entry, den emergence, and parturition were unrelated to weather and hard mast production. / Master of Science / incomplete_metadata

Ecology and physiology of black bears in Great Dismal Swamp (GDS) National Wildlife Refuge and surrounding area, a forested wetland in eastern Virginia and northeastern North Carolina, were studied from April 1984 to March 1987. A total of 101 bears (71M, 30F) were captured 120 times. Males dominated the capture sample (<u>P</u>< 0.001), but age did not differ between sexes (<u>P</u>= 0.74). Mean (±SE) age was 4.2±0.3 years. Litter size (<i>x̅</i>=2.1; N=12), modal age at primiparity (4 years), and interbirth interval (slightly greater than 2 years) were indicative of good-quality habitat. Estimated annual adult survival rates were 0.84 for females and 0.58 for males. Causes of mortality included legal (outside the Refuge) and illegal harvest, vehicle collisions, depredation permit kills, research, and predation. Population density for the study area was estimatcd by 6 techniques at 0.47-0.68 bears/km², corresponding to 262-377 bears for the 555 km² study area. Demographic data suggested a stable and productive population. Three major levels of diet quality were observed in terms of crude fiber, fat, and protein. Spring diets were high in protein but moderate in crude fiber, while fall diets were low in crude protein and high in ether extract. Condition indices and several blood characteristics (e.g. total protein, albumin, HCT, hemoglobin, and RBC) were at peaks in spring and late fall and at a low during summer. Serum creatinine concentrations also varied seasonally (<u>P</u><0.001), with a peak during denning and high levels in spring and late fall, perhaps resulting from transition from and to hibernation. A urea/creatinine (U/C) ratio ≤10 was not a good indicator of the hibernating state, as 39 of 120 (32.5%) trapped, active bears had U/C ratios ≤10. Creatinine and total protein were the best indicators of the hibernating state. Albumin, HCT, hemoglobin, and RBC were the best indicators of condition during active stages, as indicated by significant (<u>P</u>< 0.1) correlations of condition indices and blood variables. Nine blood variables varied with age (<u>P</u>< 0.1). Multivariate analysis of variance and discriminant function analysis using blood variables failed to reject the hypothesis that bears cycled through 4 metabolic stages throughout the year. Results showed that metabolic shifts were tied to concomitant seasonal changes in diet quality, diet composition, and body condition, but also may have an endogenous component. Habitat and range use dynamics were described by radiotracking of 24 female and 22 male bears. Median annual range size estimates were 79.1 km² for males (<u>N</u>=10), 33.1 km² for subadult h females (<u>N</u>=7), and 21.4 km² for adult females (<u>N</u>=11). Preferred (<u>P</u>< 0.05) habitats on an annual basis were pocosins and mesic areas for females and gum-cypress and maple-coniferous stands for males. Seasonally, pocosin, gum-cypress, mesic, and disturbed areas were important for females. Bear distribution analysis indicated that roads were preferred (<u>P</u>< 0.05) during all seasons except early fall, when bears made fall excursions to feeding areas far from Swamp roads and close to the study area boundary. Range overlap was extensive for both sexes, although it appeared that females maintained exclusive ranges during spring and early summer. Denning ecology was described by monitoring 35 bears (26F, 9M). Five bears (2M, 3F) remained active throughout the winter. Den types included 14 elaborate ground nests, 11 excavated ground cavities, 2 ground-level tree cavities, 1 above-ground-level tree cavity, and l den in a stump. Females with cubs denned earlier, (<u>P</u>< 0.02) emerged later (<u>P</u>< 0.001), and denned longer (<u>P</u>< 0.001; 119 ±4 days vs. 78 ±4 days) than all other bear groups. Dry den sites did not appear to be limited. Present population management (protection from hunting and no public vehicular access) should be continued in the Refuge. The small effective population size (N=66) in GDS indicated the need for study of dispersal and genetics in the GDS and other southeastern wetland populations to determine the degree of isolation and extent of genetic variability. Maintenance and enhancement of pocosins, mature gum, oak, and disturbed habitats would benefit black bears in southeastern wetlands by providing a wide variety of natural foods throughout the year. Large den trees may not be necessary for successful denning and reproduction in certain southeastern wetlands because bears can use dense cover and microelevational factors to overwinter. Black bear conservation strategies in the Southeast are a critical need due to increasing habitat fragmentation. Six adult female black bears were maintained in captivity in Virginia from August 1987 to April 1988. Serum samples, as well as data on body weight and rectal temperatures, were collected from each bear at approximately 10-day intervals from 25 September to 30 March. Four of the six bears hibernated, not feeding for periods of 56 to 121 days (<i>x̅</i>=94 d). Rectal temperature declined in both active and hibernating bears during winter, but to a greater extent (P= 0.013) in hibernators. Average weight loss during hibernation represented 27.9% of peak body weight. Mean serum urea/creatinine (U/C) ratios were similar between physiological groups during the prehibernation phase. However, U/C ratios differed (<u>P</u>< 0.025) after the onset of hibernation. Concentrations of total serum protein, serum urea nitrogen, and serum creatinine were similarly affected by significant time-group interactions (<u>P</u>< 0.01). Alkaline phosphatase, phosphorus, sodium, and chloride changed significantly (<u>P</u>< 0.05) during the course of the experiment, without regard to physiological group. U/C ratio was a good indicator of the hibernating state, but the sensitivity of serum urea levels to diet suggests careful use of U/C ratio as a field index. Serum progesterone (P) concentrations slowly increased from 2 to 5 ng/ml during October and November, then increased 2-2.5 fold 58 ±5 days before parturition in 2 bears that produced cubs. After the implantation peak, P declined, reaching undetectable levels 1-2 days postpartum. Similar P profiles were observed in 3 of 4 bears that did not produce any observed cubs. P also was assayed in 38 active wild black bears to relate to reproductive status in the den. Changes in serum estradiol-17<i>ß</i> concentrations during gestation also were profiled. The occurrence of pseudopregnancy or early embryonic mortality in bears with elevated serum progesterone concentrations is discussed. / Ph. D.

Thesis (M.S.)--University of Tennessee, Knoxville, 2008. / Title from title page screen (viewed on Sept. 23, 2009). Thesis advisor: Frank T. van Manen. Vita. Includes bibliographical references.

No description available.

Much of the decline of the U.S. sheep industry has been attributed to losses caused by predators. Most predatory losses are inflicted on lambs rather than ewes. Losses have historically ranged from 4-8% of lamb crops, inflicting significant financial loss on ranchers. However, most research providing data on sheep predation is over 20 years old. Changes in the sheep industry as well as predation rates may make previous loss rates inapplicable to current conditions. Coyotes (Canis latrans) are the primary predator of concern when it comes to sheep losses, but increasingly, cougars (Felis concolor) and black bears (Ursus americanus) are reported to be responsible for an increased proportion of lamb losses. I replicated a sheep depredation study conducted during the early 1970s in southwestern Utah and compared the results of the two studies to reassess losses and the predator species responsible for those losses. Total lamb losses to all causes in my study were comparable to losses reported in the 1970s as well as categories of verified and estimated predator losses. There was a significant variation in lamb losses between the 2 years of my study due to an increase in predator kills on sheep. Cougar and bear depredations occurred at significantly higher rates during my study than during the 1970s but did not produce an additive effect to overall predator losses. Most lambs killed by predators were located on or near pasture bed grounds as reported by other studies, but a large number were found >500 m from bed grounds. Rough terrain and scavenging by California condors (Gymnogyps californianus) made location of missing sheep difficult. The ability of cougars and bears to remove sheep carcasses from kill sites made the finding of sheep carcasses more difficult and caused an underreporting of sheep killed by these predators. I found that the loss of sheep to predation continues to be a problem for the sheep industry and its magnitude was unchanged from historic predation levels.

The Greater Chassahowitkza Ecosystem black bear (Ursus americanus floridanus) population of west-central Florida is likely to be the smallest documented population of the species. It has experienced almost no recruitment since 1997 and exhibits behavior that appears to be a response to human activities. The local diet is dominated by the fruit of saw palmetto and sabal palm, species that exhibit patchy distributions and irregular mast production. These food supplies are often separated by busy highways that have killed 6 bears since 1997, 21% of known individuals. Motion-activated camera surveys suggest that the bear population is declining in this rapidly urbanizing part of Florida; results of the 2002 survey estimated 28 " 18 bears in the GCE, while 2003 estimates recorded 12 " 7 individuals (Lincoln-Petersen). Additionally, blood and hair samples suggest the genetics of this population are extremely depauperate. I recommend a different fire regime in palm-dominated habitats, restoring landscape connectivity to nearby bear populations, and supplementation of the population. Because the threats to this population are manifold and its immediate future is in doubt, a combination of conservation and management tools will be required to prevent extinction of this isolated black bear population.

We evaluated the influence of a landscape dominated by agriculture and an extensive road network on fine-scale movements of black bears (Ursus americanus) in south-central Florida. The objectives of this study were to (1) define landscape functionality including corridor use by the directionality and speed of bear movements, (2) to develop a model reflecting selected habitat characteristics during movements, (3) to identify habitat characteristics selected by bears at road-crossing locations, and (3) to develop and evaluate a predictive model for road-crossing locations based on habitat characteristics. We assessed models using GPS data from 20 adult black bears (9 F, 11 M), including 382 unique road-crossing events by 16 individuals. Directionality of bear movements were influenced by the density of cover and proximity to human infrastructure, and movement speed was influenced by density of cover and proximity to paved roads. We used the Brownian bridge movement model to assess road-crossing behavior. Landscape-level factors like density of cover and density of roads appeared more influential than roadside factors, vegetative or otherwise. Model validation procedures suggested strong predictive ability for the selected road-crossing model. These findings will allow managers to prioritize and implement sound strategies to promote connectivity and reduce road collisions.

Kentucky, USA, is the site of recent natural recolonization by the American black bear (Ursus americanus); however, bears are rarely observed outside the Cumberland Mountains along the state‘s southeastern border. I examined the influence of roads in constraining the distribution of this population by altering animal space use and movement. I identified patterns of road avoidance and road crossing using data from Global Positioning System collars worn by 28 adult bears (16M, 12F), and described road mortality trends using 27 roadkill events. Bears avoided roads at the home range and landscape scale, primarily crossed low-traffic roads, and crossed in sites that minimized detection by humans. Males displayed more evidence of road avoidance than females, but females crossed roads more selectively than males. Bears were most often killed on high to moderate traffic roads, and in areas less forested than expected. Roadkill and road crossing sites bore different attributes. The results of my study support previous findings that space use near roads and road crossing reflect a tradeoff between the risks of road mortality and human harassment, and the benefits of access to habitat, mates, and anthropogenic food. Road-mediated restriction of black bear space use and movement is indicated.

Thesis (M.S.)--University of Tennessee, Knoxville, 2009. / Title from title page screen (viewed on Mar. 8, 2010). Thesis advisor: Frank T. van Manen. Vita. Includes bibliographical references.