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Mark A. Haroldson

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The Randomized Shortest Path (RSP) raster delineates potential dispersal paths for male-mediated gene flow between grizzly bear (Ursus arctos) populations in the Greater Yellowstone Ecosystem (GYE) and the Northern Continental Divide Ecosystem (NCDE). A RSP algorithm was used to estimate the average number of net passages for all grid cells at a spatial resolution of 300 m in the study region which spans parts of Montana, Idaho, and Wyoming. RSP rasters identify potential movement paths for 3 levels of random deviation determined by the parameter Θ (i.e., Θ = 0.01, 0.001, and 0.0001) for bears moving from an origin to a destination node. Lower values of Θ result in greater exploration and more random deviation around...
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For several decades, grizzly bear (Ursus arctos) populations in the Greater Yellowstone Ecosystem (GYE) and the Northern Continental Divide Ecosystem (NCDE) have increased in numbers and range extent. Whereas the NCDE population is contiguous with grizzly bear populations in the Canadian Rocky Mountains, genetic evidence suggests the GYE population remains isolated. Recent analyses indicate the effective population size of GYE grizzly bears has increased and is approaching levels needed for long-term viability. With only ~110 km distance separating current estimates of occupied range for these populations, the potential for immigration into the GYE from an NCDE migrant, or vice versa, is likely greater now than...
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