CONTENT: The biologically significant unit (BSU) is a geographical/spatial area within greater sage-grouse habitat that contains relevant and important habitats which is used as the basis for comparative calculations to support evaluation of changes to habitat. This BSU unit, or subset of this unit is used in the calculation of the anthropogenic disturbance threshold and in the adaptive management habitat trigger.

BSUs for the Idaho and Southwestern Montana GRSG EIS were derived through the overlay of several existing layers: Habitat Management Areas for the Administrative Draft Proposed PLan (ADPP) (also referred to as Alternative G), Conservation Areas, and Idaho Department of Fish and Game Nesting and Winter Habitat 2012. There are 8 BSUs in Idaho for calculating Adaptive Management Habitat Triggers. These are divided into 4 geographic areas, and subdivided into Priority or Important management areas. There is one BSU for Southwestern Montana, all Priority (Core) habitat. There is one BSU for the Raft River area in Utah, managed by the Sawtooth NF.

The intended use of all data in the BLM's GIS library is to support diverse activities including planning, management, maintenance, research, and interpretation.