In this interim progress report, we report preliminary results from an analysis of region- wide lek-count data for greater sage-grouse from the Powder River Basin (PRB) in relation to coal-bed natural gas (CBNG) development. We have completed the first of four separate, but related analyses of these data. Preliminary results support previous findings that region-wide populations declined severely in 1990-1995, followed by stable trends around a lower population equilibrium from 1995-2005. However, leks with extensive CBNG development (>40% developed within 3.2 km) showed substantially lower population trends than leks with minimal CBNG or no development, even after controlling for known impacts of West Nile virus. Leks in areas adjacent to CBNG fields (10-40% developed within 3.2 km) also showed higher population trends than leks further away, suggesting that sage-grouse may be avoiding developed areas and moving into adjacent undeveloped habitat. The avoidance hypothesis is supported by the finding that, by 2005, active leks, and large and medium-sized leks, were more often found outside or adjacent to CBNG fields than within CBNG. Expansion of agriculture and surface mining also appears to have played a role in regional population changes in the PRB.
