Michael R. Vaughan

Parathyroid hormone may maintain bone formation in hibernating black bears (Ursus americanus) to prevent disuse osteoporosis.

SUMMARY Mechanical unloading of bone causes an imbalance in bone formation and resorption leading to bone loss and increased fracture risk. Black bears (Ursus americanus) are inactive for up to six months during hibernation, yet bone mineral content and strength do not decrease with disuse or aging. To test whether hibernating bears have biological mechanisms to prevent disuse osteoporosis, we measured the serum concentrations of hormones and growth factors involved in bone metabolism and correlated them with the serum concentration of a bone formation marker (osteocalcin). Serum was obtained from black bears over a 7-month duration that included periods of activity and inactivity. Both resorption and formation markers increased during hibernation, suggesting high bone turnover occurred during inactivity. However, bone formation appeared to be balanced with bone resorption. The serum concentration of parathyroid hormone (PTH) was higher in the hibernation (P=0.35) and post-hibernation (P=0.006) seasons relative to pre-hibernation levels. Serum leptin was lower (P<0.004) post-hibernation relative to pre-hibernation and hibernation periods. Insulin-like growth factor I (IGF-I) decreased (P<0.0001) during hibernation relative to pre-hibernation and reached its highest value during remobilization. There was no difference (P=0.64) in 25-OH vitamin D between the three seasons. Serum osteocalcin (bone formation marker) was significantly correlated with PTH, but not with leptin, IGF-I or 25-OH vitamin D. Osteocalcin and PTH were positively correlated when samples from all seasons were pooled and when only hibernation samples were considered, raising the possibility that the anabolic actions of PTH help maintain bone formation to prevent disuse osteoporosis. Prostaglandin E2 (PGE2) release from MC3T3 osteoblastic cells was significantly affected by treatment with bear serum from different seasons (i.e. hibernation versus active periods). The seasonal changes in PGE2 release showed trends similar to the seasonal changes in serum IGF-I. Since both PGE2 and IGF-I are associated with collagenous bone formation, it is possible that seasonal changes in a circulating factor influence IGF-I levels in vivo in bears and PGE2 release in osteoblastic cells in vitro. The significant decrease in serum leptin following arousal from hibernation may promote bone formation during remobilization, assuming there is a similar decrease in intracerebroventricular leptin. These findings support the idea that seasonal changes in the concentration of circulating molecules help regulate bone formation activity and may be important for preventing disuse osteoporosis in bears.

Denning Ecology of Black Bears in a Southeastern Wetland

We investigated den characteristics and denning chronology of black bears (Ursus americanus) in the Great Dismal Swamp (GDS), a forested wetland in Virginia and North Carolina. We monitored 35 bears (26 F, 9 M) throughout the winters of 1984-85, 1985-86, and 1986-87. Den types included 14 ground nests, 11 excavated ground cavities, 2 ground-level tree cavities, 1 above-ground-level tree cavity, and 1 stump den. Three dens were in areas of inundation. Pregnant females entered dens earlier (P < 0.02), emerged later (P < 0.001), and denned longer (119 ? 4 [SE] vs. 78 ? 4 days) than other age and sex groups. Denning periods were among the shortest reported for black bears. Although den site availability was not estimated, dry den sites did not seem to be limited. 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

Demographic analysis of a black bear population in the Great Dismal Swamp

During April 1984-August 1986, 101 black bears (Ursus americanus) (71 M, 30 F) were captured 120 times in the Great Dismal Swamp (GDS) National Wildlife Refuge (NWR) and surrounding area, a forested wetland in eastern Virginia and northeastern North Carolina. Males dominated the capture sample (P 9 years old were male (n = 5). Litter size (n = 12, : = 2.1), suspected modal age at primiparity (4 yr), and interbirth interval (approx 2 yr) were indicative of good-quality habitat. Estimated annual survival rates were 0.87 for females (-1.5 yr) and 0.59 for males (?2.5 yr). Causes of mortality included legal and illegal harvest, vehicle collisions, depredation permit kills, research, and intraspecific predation. Estimated bear density was 0.52-0.66 bears/km2, corresponding to 286-368 bears for the 555-km2 study area. Present population management (protection from hunting and no public vehicular access) should be continued in the GDSNWR. The small effective population size (N, = 56) in the 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. Black bear conservation strategies in the southeast are critical due to increasing habitat fragmentation. J. WILDL. MANAGE. 53(4):969-977 The ecology of black bears in southeastern wetlands has been the subject of limited study (Hamilton 1978, Smith 1985). Islands of wetland habitats, primarily swamps and pocosins (Sharitz and Gibbons 1982), provide the last remaining refuges for black bear on the Atlantic Coastal Plain (Monschein 1981, Zeveloff 1983). Large hardwood swamps and pocosins provide excellent denning habitat (Hamilton and Marchinton 1980, Hellgren and Vaughan 1989), diverse food supplies, and protection from disturbance (Hamilton 1978, Monschein 1981). However, dynamics of wetland populations remain poorly understood. The GDS, an 850-km2 forested wetland on the Virginia and North Carolina border, supports the last breeding population of black bears in eastern Virginia and extreme northeastern North Carolina. The 1973 establishment of GDSNWR, which occupies the core of the swamp, placed management responsibility for the bear population on the U.S. Fish and Wildlife Service (USFWS). The need for population estimates and evaluation of habitat suitability for proper bear management in GDSNWR was ide tified (Bur. Sport Fish. and Wildl. 1974), yet bear-related research has not met this need. Management for bears in the GDSNWR is limited to protection from hunting. The GDS population, although afforded sanctuary in the refuge and unhunted in North Carolina since the early 1970s, is exploited on private swamp land in Virginia at a rate of 9.4 bears/year since refuge establishment (Anonymous 1984). The potential of the unhunted population in GDSNWR to act as a reservoir for black bear reproduction and dispersal in the Atlantic Coastal Plain is unknown. In recent years, clearing of privately-owned GDS land for agricultural or residential development has accelerated, making GDSNWR vital as a sanctuary for the bear population. Information such as sex and age distribution, age at primiparity, birth rate, survival, and density of the bear population in the GDS is necessary to predict results of bearrelated management actions. Our objective was to characterize dynamics of the black bear population in the GDS. We acknowledge the cooperation of the USFWS, Virginia Department of Game and Inland Fisheries, North Carolina Wildlife Resources Commission, and the Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University. Particularly helpful were D. J. Schwab, R. D. Mc1 Present address: Campus Box 218, Caesar Kleberg Wildlife Research Institute, Texas A&I University, Kingsville, TX 78363.

Increased oxidative stress and decreased activities of Ca2+/Mg2+-ATPase and Na+/K+-ATPase in the red blood cells of the hibernating black bear

During hibernation, animals undergo metabolic changes that result in reduced utilization of glucose and oxygen. Fat is known to be the preferential source of energy for hibernating animals. Malonyldialdehyde (MDA) is an end product of fatty acid oxidation, and is generally used as an index of lipid peroxidation. We report here that peroxidation of lipids is increased in the plasma and in the membranes of red blood cells in black bears during hibernation. The plasma MDA content was about four fold higher during hibernation as compared to that during the active, non-hibernating state (P < 0.0001). Similarly, MDA content of erythrocyte membranes was significantly increased during hibernation (P < 0.025). The activity of Ca(2+)/Mg(2+)-ATPase in the erythrocyte membrane was significantly decreased in the hibernating state as compared to the active state. Na(+)/K(+)-ATPase activity was also decreased, though not significant, during hibernation. These results suggest that during hibernation, the bears are under increased oxidative stress, and have reduced activities of membrane-bound enzymes such as Ca(2+)/Mg(2+)-ATPase and Na(+)/K(+)-ATPase. These changes can be considered part of the adaptive for survival process of metabolic depression.

Seasonal Variation in American Black Bear Ursus americanus Activity Patterns: Quantification Via Remote Photography

Activity pattern plasticity may serve as an evolutionary adaptation to optimize fitness in an inconstant environment, however, quantifying patterns and demonstrating variation can be problematic. For American black bears Ursus americanus, wariness and habitat inaccessibility further complicate quantification. Radio telemetry has been the primary technique used to examine activity, however, interpretation error and limitation on numbers of animals available to monitor prevent extrapolation to unmarked or untransmittered members of the population. We used remote cameras to quantify black bear activity patterns and examined differences by season, sex and reproductive class in the Alleghany Mountains of western Virginia, USA. We used 1,533 pictures of black bears taken during 1998–2002 for our analyses. Black bears generally were diurnal in summer and nocturnal in autumn with a vespertine activity peak during both seasons. Bear-hound training seasons occurred during September and may offer explanation for the observed shift towards nocturnal behaviour. We found no substantial differences in activity patterns between sex and reproductive classes. Use of remote cameras allowed us to efficiently sample larger numbers of individual animals and likely offered a better approximation of population-level activity patterns than individual-level, telemetry-based methodologies.

Mule Deer Movements in Response to Military Activity in Southeast Colorado

During January 1986-September 1988 we studied the behavioral responses of 71 radiocollared mule deer (Odocoileus hemionus) to military activity on the Pinon Canyon Maneuver Site in southeastern Colorado. Military training was initiated on the site during August 1985 and recurred about 3 times yearly for periods of one month. During a maneuver, 3/7 of the site was used for training in accordance with a rotational land use schedule. During the nonsummer seasons, female seasonal convex polygon and harmonic mean home ranges were larger in maneuver and previous-maneuver areas than nonmaneuver areas (P < 0.002). During summer, female convex polygon home ranges were larger in maneuver than nonmaneuver areas (P = 0.066). Fawn summer home ranges were larger in maneuver than previous-maneuver areas (P < 0.01). Male home range sizes differed only for 50% harmonic mean transformation annual home ranges (P = 0.056); bucks in maneuver areas had larger home ranges than in nonmaneuver areas. Female deer in maneuver areas exhibited significant home area shifts (P = 0.049) between premaneuver and maneuver periods more frequently (40.0%) than did deer in nonmaneuver (control) areas (12.5%). Mule deer in military training areas may have responded to human harassment, alteration of security cover, or destruction of the forage base. We suggest that deer may respond more intensely to unpredictable than predictable human activity.

Habitat use and movements of American black ducks in winter

We determined habitat use and movement patterns of 22 female American black ducks (Anas rubripes) wintering at Chincoteague National Wildlife Refuge (NWR), Virginia, with radio telemetry and aerial survey techniques during 15 December 1985-28 February 1986. Proportional use of saltmarsh, impoundment, and natural pool habitats was greater (P 1. Habitat use was affected by the day-night cycle and a tide-ice interaction. J. WILDL. MANAGE. 53(2):390-400 American black duck populations wintering along the Atlantic Flyway have declined almost 50% since 1954 (Steiner 1984). Excessive harvest (Geis et al. 1971, Blandin 1982, Grandy 1983), acid rain (Hansen 1987), and hybridization with mallards (Anas platyrhynchos) (Heusmann 1974, Ankney et al. 1987) have been suggested as factors responsible for this decline. Others believe that loss and degradation of wintering habitat may be affecting black duck populations, although the evidence is somewhat con-

Evaluating scientific inferences about the Florida panther

Abstract At the request of the U.S. Fish and Wildlife Service (USFWS) and the Florida Fish and Wildlife Conservation Commission (FWC), we provide an independent assessment of the reliability of the scientific literature used to support conservation of Florida panthers (Puma concolor coryi). We independently reached similar conclusions about unreliable scientific inferences before discussing the issues with each other or with others. Although a quarter-century of research supports many published conclusions, 2 sets of unreliable inferences may compromise efforts to conserve the species. The first is a set of 4 unreliable inferences that underlie the Panther Habitat Evaluation Model (PHEM), used by agencies to evaluate projects that may affect panther habitat. Specifically, the following assertions are unreliable: 1) panthers are forest obligates, 2) panthers require large (>500 ha) forest patches, 3) panthers are reluctant to cross 90-m gaps of nonforest habitat, and 4) the value of potential panther habitat declines linearly with distance to a population core in south Florida, USA. These assertions are unreliable because the analyses excluded (without mention or rationale) almost half the available data, compared used habitats to an inappropriate set of available habitats, made inferences about habitat preference without any data on available habitats, were based only on panther locations during daytime, ignored telemetry error, or suffered from other flaws. The second is a set of 2 unreliable inferences about panther demography prior to the genetic restoration effort initiated in 1995. Inferences that neonate survival was ≥0.84 and that the panther population was demographically vigorous prior to 1995 are flawed because the survival analysis ignored mortality during the first 4 months and because other inferences were based on numbers of births and deaths in samples of convenience rather than appropriate vital rates. These faulty inferences about panther demography brought unwarranted credibility to challenges of the genetic restoration program. Faulty inferences of both sets were repeated in subsequent scientific and popular articles; in several instances, previously published work was mis-cited. In its current (2002–2005) version, PHEM is unreliable and should not be used in decisions about panther habitat. Biologists should obtain better demographic estimates and fully analyze how the introgression program has affected these rates.

Sub-sampling Genetic Data to Estimate Black Bear Population Size: A Case Study

Abstract Costs for genetic analysis of hair samples collected for individual identification of bears average approximately US

Bone formation is not impaired by hibernation (disuse) in black bears Ursus americanus

50 [2004] per sample. This can easily exceed budgetary allowances for large-scale studies or studies of high-density bear populations. We used 2 genetic datasets from 2 areas in the southeastern United States to explore how reducing costs of analysis by sub-sampling affected precision and accuracy of resulting population estimates. We used several sub-sampling scenarios to create subsets of the full datasets and compared summary statistics, population estimates, and precision of estimates generated from these subsets to estimates generated from the complete datasets. Our results suggested that bias and precision of estimates improved as the proportion of total samples used increased, and heterogeneity models (e.g., Mh[Chao]) were more robust to reduced sample sizes than other models (e.g., behavior models). We recommend that only high-quality samples (>5 hair follicles) be used when budgets are constrained, and efforts should be made to maximize capture and recapture rates in the field.