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Project
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Interagency Brown Bear Study TeamNatural resources management on the Kenai Peninsula is a complicated affair. Multiple state and federal agencies have jurisdiction over various resources. Patchy land ownership on the Peninsula presents a challenge to the management of widely ranging species, such as the brown bear (Ursus arctos). Thus, the Interagency Brown Bear Study Team (IBBST) was formed in 1984 to conduct research on the basic ecology of the Kenai brown bear population. Scientists from the Alaska Department of Fish and Game (ADF&G), the U.S. Fish and Wildlife Service, the U.S. National Forest Service, and the U.S. National Park Service comprise the IBBST. BackgroundThe Kenai Peninsula ecosystem has changed considerably over the last 10 years. Disturbance and habitat loss have come in many forms. The human population has roughly doubled. The spruce bark beetle has killed much of the spruce south of Lake Tustumena, and many areas have been logged to salvage beetle-killed timber. These pressures can lead to increases in bear-human interactions that can be dangerous for both humans and bears. To further complicate things, there is no scientific estimate of the size of the brown bear population on the Peninsula. The dense vegetation of the Peninsula makes accurate aerial surveys impossible. And, until the mid-1990s, and the advent of Global Positioning System (GPS) radio-collars, brown bear movements were difficult to follow. In response to concerns about the brown bear population, the IBBST was formed and to study brown bear movement, physiology, and habitat requirements. The data being collected will help biologists and managers understand the resource needs and range requirements of the species. Goals and ObjectivesThe goal of the IBBST is to investigate the basic ecology of brown bears on the Kenai Peninsula. MethodsADF&G biologists are using GPS technology and aerial radio-tracking (VHF) to document brown bear locations on the Kenai Peninsula. Several bears have been handled in the Kachemak Bay Watershed. Through 1998, only females had been collared. In 1999, a newly developed collar was tested to follow males from spring until midsummer. The GPS collars are recovered and replaced each spring and/or fall so that the GPS data can be downloaded and analyzed. Various physiological measurements are also taken, including weight, body composition (protein:fat), and age. Hair and blood samples are collected for stable isotope analysis, which allows estimation of the relative contribution of salmon, terrestrial meat, and plant matter to the diet of brown bears. Fat biopsies are taken for development of a new technique (fatty acid analysis) that may define bear diets more specifically. Members of the team have also developed a model of the cumulative impacts of human use and development, resource extraction, and landscape modification on brown bear habitat. ResultsSince 1995, 88 bears distributed across the Peninsula have been found in over 9,000 locations collected by GPS or VHF. Several bears have traveled in and out of the Watershed over those years. The age range of bears handled (not necessarily collared) is 0 to 22 years. The mortality rate of collared brown bears, south of Lake Tustumena, is twice that of collared bears on the rest of the Kenai Peninsula. This is likely due to a high rate of human-caused mortality (e.g., legal harvest, defense of life, property kills, and poaching), which is the function of a changing ecosystem characterized by increased human usage and access. Salmon are a critical resource to Kenai brown bears. From the time of salmon arrival in the summer, to the time of den entry in the fall, salmon accounts for 60 percent of the diet of female brown bears (Hilderbrand et al. 2000). During this time period, the average adult female puts on about 140 pounds of body weight, of which about 80 percent is fat (Hilderbrand et al. 2000). This accumulation of nutritional reserves from the salmon resource is critical to population productivity (Hilderbrand et al. 1999). Suring et al. (1998) modeled the cumulative impacts of human usage and development, resource extraction, and landscape modification on brown bear habitat on the Peninsula. Their findings suggest that it is the quality (effectiveness) of the remaining brown bear habitat, not the quantity, that is important for brown bear population protection. DurationWhile much has been learned about Kenai brown bears, questions remain. The IBBST's telemetry and GPS work will continue with a shift in focus to the movements, needs, and physiology of male bears. Additionally, the IBBST may work in conjunction with the University of Alaska, Fairbanks to implant temperature sensors in the bruins to understand their energetics during hibernation. A technique using genetics to provide a scientific estimate of the Peninsula brown bear population size is currently under development by the IBBST. Finally, continued data collection will allow IBBST scientists to test and refine the cumulative effects model. Project LeaderSean Farley ReferencesHilderbrand, G.V., C.C. Schwartz, C.T. Robbins, M.E. Jacoby, T.A. Hanley, S.M. Arthur, and C. Servheen. 1999. Importance of meat, particularly salmon to body size, population productivity, and conservation of North American brown bears. Canadian Journal of Zoology 77:132-138. Hilderbrand, G.V., S.G. Jenkins, C.C. Schwartz, T.A., Hanley, and C.T. Robbins. 2000. Effect of seasonal, dietary meat intake on changes in body mass and composition in wild and captive brown bears. Canadian Journal of Zoology 78:1623-1631. Suring, L. H., K. R. Barber, C. C. Schwartz, T. N. Bailey, W. C. Shuster, and M. D. Tetreau. 1998. Analysis of cumulative effects on brown bears on the Kenai Peninsula, south central AK. Ursus 10:107-117. |
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Contact: Coowe Moss-Walker (coowe_walker@fishgame.state.ak.us) |
