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Population delineation of barren-ground grizzly bears in the central Canadian Arctic

2016; Wiley; Volume: 30; Issue: 3 Linguagem: Inglês

1938-5463

Philip D. McLoughlin, H. Dean Cluff, Robert J. Gan, Robert Mulders, Ray L. Case, François Messier,

Wildlife-Road Interactions and Conservation

We identified spatially distinct populations of barren-ground grizzly bears (Ursus arctos) in a 235,000-km2 study area northeast of Yellowknife, Northwest Territories, Canada. We tested for the presence of population clusters of bears using movement data obtained from satellite telemetry (n=55 female bear-years, n=42 male bear-years) and multivariate cluster analysis. We identified geographic range of female and male population clusters using the fixed-kernel range estimator with least-squares cross-validating to determine bandwidths, and defined population unit boundaries by referring to the 70%/0 contours of population ranges. To validate population units, we required spatial clusters for female and male bears to be similar so distinctive female and male components could be con- tained within common population boundaries. Further, we needed population growth rates to be a result of intrinsic birth and death rates and not immigration or emigration rates. Thus, no more than 1 radiotracked animal of either sex (between 2.1/% and 4.3o/o of a given population unit sample) could immigrate to or emigrate from an identified pop- ulation unit annually. We obtained independent clustering solutions that grouped both female and male grizzly bears into 3 areas: the North Slave region, Bathurst Inlet region, and Kugluktuk region. Although female population ranges at the 70% contour level were completely contained within established population unit boundaries, male population ranges demonstrated overlap. Annual exchange rates were high (3.4-1 3% for females, 7-35o/o for males) among the 3 population groups. Bears in our study area should thus be managed as an open (continuous) population.