The sagebrush (Artemisia spp.) ecosystem once occupied over 150 million acres of western North America (Barbour and Billings 1988). The ecosystem still occupies over 100 million acres (Connelly et al. 2004, Wisdom et al. 2005), but the abundance and condition of sagebrush communities is declining rapidly in response to a variety of detrimental land uses and undesirable ecological processes (Knick et al. 2003). The ecosystem has been reduced in area by 40-50 percent since pre-European settlement (Connelly et al. 2004), and less than 10 percent remains in a condition unaltered by human disturbances (West 1999).