Structures Data Collection Assists Grizzly Bear Recovery Project

Limited to less than two percent of their original range in the lower 48 United States, grizzly bears (Ursus arctos horribilis) were listed as a threatened species in 1975 under the Endangered Species Act. With this legislation came the responsibility for regional land and wildlife managers to monitor their recovery. The Northern Continental Divide Ecosystem (NCDE) in northwest Montana is one of the last strongholds of the grizzly bear in the lower 48 states. In 2008 NOROCK’s Northern Divide Grizzly Bear Project (NDGBP) completed a study that provides a better understanding of the population size, distribution, and genetic health of grizzly bears in northwest Montana and determined a complete population estimate of 765 grizzly bears making their home in the NCDE.

Though grizzly bear population size is better understood, little information exists about the variables influencing bear abundance in the NCDE. One known variable that impacts grizzly bear abundance is the density of manmade structures which relates to human activity within the recovery zone. The USGS National Geospatial Program supported this science by building a cooperative structures collection project between the NDGBP and the State of Montana which leveraged funds to collect structure density data in western Montana as well as supporting the ongoing data collection and maintenance requirements of the Montana Structures Framework and the USGS National Map. The Montana Structures Framework is designed to support a wide range of uses for a statewide, standardized structures layer, from emergency response, to planning, to natural resource studies such as the grizzly bear recovery project. USGS Geospatial Liaison to Montana, Lance Clampitt, worked on the project with the NCDGP lead Kate Kendall.