Grizzly Bear Trend Monitoring Research in the NCDE: An Update, 2004-2008

Abstract

In 2004, monitoring of grizzly bear (Ursus arctos) population trend in the Northern Continental Divide Ecosystem (NCDE) was initiated by Montana Fish, Wildlife and Parks (MFWP) in cooperation with other state and federal agencies. Also in 2004 an interagency field effort was undertaken to enumerate population size of grizzly bears over the entire NCDE using DNA methods. From these data, researchers have recently estimated population size with confidence limits and relative bear density across the NCDE. However, Managers and the public agree that a companion program is needed that would track population trend and female vital rates over time and provide ancillary information on other indices of population health. Having estimates of both size and trend will greatly improve our collective knowledge of grizzly bear ecology and provide more measurable and precise information with which to judge the status of the grizzly population in the NCDE. The purpose of this long term trend program is to monitor the vital population parameters of grizzly bears by assessing the survival and reproductive rates, as well as trend, by following a number of radio-collared female grizzly bears. We summarize the objectives and field design of population trend and report on our success to date.