Movement Ecology and Activity Behavior of Black Bears in the Great Smoky Mountains National Park

Movements and activity behavior of 29 radio-collared black bears (Ursus americanus) were monitored between July 1976 and December 1977 in the Great Smoky Mountains National Park. Many bears exhibited home ranges with abrupt seasonal changes, especially between summer and fall. The timing and extent of these range shifts were influenced by sex, age and food availability. During good mast years, the fall ranges of many males overlapped considerably in an area of abundant oaks, while during poor mast years, social intolerance may force many subordinate males outside the Park boundaries in search of food. Fall movements increased the size of annual home ranges above previously reported estimates based strictly on summer data. Mean annual range size was 42 km2 for adult males and 15 km2 for adult females. Bears were generally more active in the summer, but traveled greater distances in a day during the fall. This was attributable to extended nocturnal activity in the fall probably associated with increased foraging in preparation for denning. A strictly crepuscular pattern was observed in the spring. Females with cubs were equally active throughout the year and were more active than any other sex-age group. Temperatures above 25 C or below freezing, and precipitation in the form of rain or snow apparently depress the level of activity

Monitoring the wild black bear's reaction to human and environmental stressors

<p>Abstract</p> <p>Background</p> <p>Bears are among the most physiologically remarkable mammals. They spend half their life in an active state and the other half in a state of dormancy without food or water, and without urinating, defecating, or physical activity, yet can rouse and defend themselves when disturbed. Although important data have been obtained in both captive and wild bears, long-term physiological monitoring of bears has not been possible until the recent advancement of implantable devices.</p> <p>Results</p> <p>Insertable cardiac monitors that were developed for use in human heart patients (Reveal® XT, Medtronic, Inc) were implanted in 15 hibernating bears. Data were recovered from 8, including 2 that were legally shot by hunters. Devices recorded low heart rates (pauses of over 14 seconds) and low respiration rates (1.5 breaths/min) during hibernation, dramatic respiratory sinus arrhythmias in the fall and winter months, and elevated heart rates in summer (up to 214 beats/min (bpm)) and during interactions with hunters (exceeding 250 bpm). The devices documented the first and last day of denning, a period of quiescence in two parturient females after birthing, and extraordinary variation in the amount of activity/day, ranging from 0 (winter) to 1084 minutes (summer). Data showed a transition toward greater nocturnal activity in the fall, preceding hibernation. The data-loggers also provided evidence of the physiological and behavioral responses of bears to our den visits to retrieve the data.</p> <p>Conclusions</p> <p>Annual variations in heart rate and activity have been documented for the first time in wild black bears. This technique has broad applications to wildlife management and physiological research, enabling the impact of environmental stressors from humans, changing seasons, climate change, social interactions and predation to be directly monitored over multiple years.</p

The Shared Preference Niche of Sympatric Asiatic Black Bears and Sun Bears in a Tropical Forest Mosaic

Ecologically similar species often coexist by partitioning use of habitats or resources. Such partitioning can occur through divergent or shared niches. We investigated overlap in habitat use and spatial co-occurrence by sympatric Asiatic black bears and sun bears in three habitats in Thailand, and thereby assessed which niche model best accounts for their coexistence.We used density of species-specific signs to assess habitat use. Signs of both bear species occurred in all three habitats, and on >60% of sampling transects. Both species fed mostly on fruit; insect feeding signs were uncommon, and were mostly from sun bears. Significant differences in habitat use occurred only in montane forest, the habitat in which fruit was most abundant; incidence of black bear sign there was six times higher than that of sun bears. Habitat use was similar between the two species in the other habitats, which comprised 85% of the area. Of 10 habitat attributes examined, fruiting tree density was the best predictor of occurrence for both species. Models that included interspecific competition (fresh foraging activity of the other species) were less supported than the top models without competition.Bear species co-occurrence at both coarse and fine spatial scales and use of the same resources (fruit trees) indicated common niche preferences. However, their habitat use differed in ways expected from their physical differences: larger black bears dominated in the most fruit-rich habitat, and smaller sun bears used less-preferred insects. These results indicate broadly overlapping fundamental niches combined with asymmetric competition—features consistent with the concept of shared preference niches. This model of the niche has received little attention in ecology, but appears to be relatively common in nature

Does the Vulnerable sun bear Helarctos malayanus damage crops and threaten people in oil palm plantations?

Largely as a result of the expansion of oil palm Elaeis guineensis, forest fragmentation has occurred on a large scale in Borneo. There is much concern about how forest-dependent species, such as the Vulnerable sun bear Helarctos malayanus, can persist in this landscape. The absence of sufficient natural food in forest fragments could drive sun bears into oil palm plantations, where they risk coming into conflict with people. We interviewed oil palm plantation workers and farmers in the Lower Kinabatangan region of Sabah, Malaysian Borneo, to ascertain if sun bears were utilizing plantations, if they were causing damage to the crop, and how the bears were perceived by people. To obtain a comparative baseline we extended these questions to include other species as well. We found that bears were rarely encountered in plantations and were not considered to be destructive to the oil palm crop, although they were generally feared. Other species, such as macaques Macaca spp., bearded pigs Sus barbatus, and elephants Elephas maximus, had more destructive feeding habits. Sun bears could use this readily available food resource without being targeted for retribution, although incidental human-related mortality remains a risk. Although bears could gain some nutritional benefit from oil palm, plantations do not provide the diversity of food and cover available in a natural forest

Increased stress in Asiatic black bears relates to food limitation, crop raiding, and foraging beyond nature reserve boundaries in China

AbstractAsiatic black bears (Ursus thibetanus) are declining throughout much of their range. In China they are partially protected by a nature reserve system and rely heavily on hard mast as a food source prior to winter denning. Bears may compensate for mast shortages by raiding agricultural crops and killing livestock, mainly outside reserves where they are exposed to increased threats of poaching. We hypothesized that stress would vary with availability of high-quality refugia and fluctuations in mast abundance. We collected fecal samples from free-ranging bears in and around nature reserves in southwestern China, recorded habitat characteristics at each fecal sample location, and quantified abundance of hard mast. We used feces for genetic and endocrine analysis and identified 106 individuals. Feces collected outside reserves, or in agricultural fields within reserves, contained elevated concentrations of glucocorticoid metabolites compared to samples collected in intact, mast-producing forests within reserves. Relationships with habitat variables indicated that the hypothalamic–pituitary–adrenal (HPA) axis of the Asiatic black bear is responsive to human activity, abundance of hard mast, extent of forest cover, and quality of diet. Our findings demonstrate biological reactions of a large mammal to variable forest quality, human threats, and foraging relative to boundaries of protected areas

Survival strategies of a frugivore, the sun bear, in a forest-oil palm landscape

As large areas of forest are lost throughout the tropics, prime habitat of many species decline and become fragmented. The island of Borneo is a prime example, with accelerated clearing of forests primarily for oil palm expansion. Borneo is recognized as an important stronghold for the conservation of the sun bear (Helarctos malayanus), but it is unclear how habitat reduction and fragmentation is affecting this frugivore. We used camera traps and sign surveys to understand patterns of sun bear habitat use in a matrix of fragmented forests and extensive oil palm development, which has existed as such for > 15 years: the Lower Kinabatangan floodplain in Sabah, Malaysian Borneo. Within these small forest fragments, squeezed between a major river and oil palm plantations, bears exhibited selection for areas farther from human activity (plantations, river boat traffic, and buildings), and were rarely active during the day, demonstrating both spatial and temporal avoidance of potential human-related threats. They selected large trees to feed and rest, and also exploited adjacent plantations to feed on oil palm fruits. We conclude that even relatively small forest fragments (~ 2000 ha) within large agricultural landscapes can be important for sun bears. Our research highlights the remarkable adaptations this species has employed to persist in a drastically modified landscape

A Stated Preference Investigation into the Chinese Demand for Farmed vs. Wild Bear Bile

Farming of animals and plants has recently been considered not merely as a more efficient and plentiful supply of their products but also as a means of protecting wild populations from that trade. Amongst these nascent farming products might be listed bear bile. Bear bile has been exploited by traditional Chinese medicinalists for millennia. Since the 1980s consumers have had the options of: illegal wild gall bladders, bile extracted from caged live bears or the acid synthesised chemically. Despite these alternatives bears continue to be harvested from the wild. In this paper we use stated preference techniques using a random sample of the Chinese population to estimate demand functions for wild bear bile with and without competition from farmed bear bile. We find a willingness to pay considerably more for wild bear bile than farmed. Wild bear bile has low own price elasticity and cross price elasticity with farmed bear bile. The ability of farmed bear bile to reduce demand for wild bear bile is at best limited and, at prevailing prices, may be close to zero or have the opposite effect. The demand functions estimated suggest that the own price elasticity of wild bear bile is lower when competing with farmed bear bile than when it is the only option available. This means that the incumbent product may actually sell more items at a higher price when competing than when alone in the market. This finding may be of broader interest to behavioural economists as we argue that one explanation may be that as product choice increases price has less impact on decision making. For the wildlife farming debate this indicates that at some prices the introduction of farmed competition might increase the demand for the wild product

The status of the world's land and marine mammals: diversity, threat, and knowledge

Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and distribution of the world's mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action