This technical document supports the Forest Service's requirement to assess the status of renewable natural resources as mandated by the Forest and Rangeland Renewable Resources Planning Act of 1974. It updates past reports on the trends and geographic patterns of species formally listed as threatened or endangered under the Endangered Species Act of 1973. We compare the geographic occupancy of threatened and endangered species at the county-level against the geographic occupancy of a broader set of species thought to be at risk of extinction. This is done to determine if new areas where species rarity may be concentrated emerge. Here we document whether past trends and geographic occupancy patterns have changed over time, thereby providing resource planners and conservation practioners with updated information on where they should focus biodiversity conservation efforts.
Flather, Curtis H.; Knowles, Michael S.; McNees, Jason. 2008. Geographic patterns of at-risk species: A technical document supporting the USDA Forest Service Interim Update of the 2000 RPA Assessment. Gen. Tech. Rep. RMRS-GTR-211. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 21 p.