Demographics and Population Trends of Grizzly Bears in the Cabinet-Yaak and Selkirk Ecosystems of British Columbia, Idaho, Montana, and Washington

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We summarize and report survival and cause-specific mortality of grizzly bears in the Cabinet-Yaak and Selkirk Mountains recovery zones from 1983-2002 to examine effects on the populations. Fifty-four percent of total known mortality in the Cabinet-Yaak was human-caused (n = 28) and 80% of total known mortality in the Selkirk Mountains was human-caused (n = 40). We investigated demographic values of 53 and 61 radiocollared grizzly bears (Ursus arctos) and attendant offspring in the Cabinet-Yaak and Selkirk Mountains recovery zones, respectively from 1983-2002. Nineteen mortalities of radiocollared animals or offspring were detected in the Cabinet-Yaak sample and 20 in the Selkirk Mountains. Estimated survival rates were 0.929 (95% CI = 0.091) for adult females, 0.847 (95% CI = 0.153) for adult males, 0.771 (95% CI = 0.208) for subadult females, 0.750 (95% CI = 0.520) for subadult males, 0.875 (95% CI = 0.231) for yearlings, and 0.679 (95% CI = 0.179) for cubs in the Cabinet-Yaak. Estimated survival rates for the Selkirk Mountains were 0.936 (95% CI = 0.064) for adult females, 0.908 (95% CI = 0.102) for adult males, 0.900 (95% CI = 0.197) for subadult females, 0.765 (95% CI = 0.176) for subadult males, 0.784 (95% CI = 0.178) for yearlings, and 0.875 (95% CI = 0.125) for cubs. Reproductive rates were 0.291 and 0.284 female cubs/year/adult female for the Cabinet-Yaak and Selkirk Mountains recovery zones, respectfully. The annual exponential rate of increase (r) was -0.037 for the Cabinet-Yaak recovery zone and 0.018 for the Selkirk Mountains.