Grizzly Bear Density in Glacier National Park,Montana |
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Authors: | KATHERINE C KENDALL JEFFREY B STETZ DAVID A ROON LISETTE P WAITS JOHN B BOULANGER DAVID PAETKAU |
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Institution: | 1. University of Montana Cooperative Ecosystem Studies Unit, Glacier Field Station, Glacier National Park, West Glacier, MT 59936, USA;2. Department of Fish and Wildlife Resources, University of Idaho, Moscow, ID 83844–1136, USA;3. Integrated Ecological Research, 924 Innes Street, Nelson, BC V1L 4L4, Canada;4. Wildlife Genetics International, Box 274, Nelson, BC V1L 5P9, Canada |
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Abstract: | Abstract: We present the first rigorous estimate of grizzly bear (Ursus arctos) population density and distribution in and around Glacier National Park (GNP), Montana, USA. We used genetic analysis to identify individual bears from hair samples collected via 2 concurrent sampling methods: 1) systematically distributed, baited, barbed-wire hair traps and 2) unbaited bear rub trees found along trails. We used Huggins closed mixture models in Program MARK to estimate total population size and developed a method to account for heterogeneity caused by unequal access to rub trees. We corrected our estimate for lack of geographic closure using a new method that utilizes information from radiocollared bears and the distribution of bears captured with DNA sampling. Adjusted for closure, the average number of grizzly bears in our study area was 240.7 (95% CI = 202–303) in 1998 and 240.6 (95% CI = 205–304) in 2000. Average grizzly bear density was 30 bears/1,000 km2, with 2.4 times more bears detected per hair trap inside than outside GNP. We provide baseline information important for managing one of the few remaining populations of grizzlies in the contiguous United States. |
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Keywords: | bear rub trees DNA Glacier National Park grizzly bear hair traps Huggins closed mixture model mark-recapture noninvasive genetic sampling population density Ursus arctos |
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