Primary Investigator: Matt Holloran, University of Wyoming
Funding: U.S. Department of Energy, Ultra Petroleum, WY Game and Fish Department, Bureau of Land Management (BLM), Shell, EnCana
Period of Study: 1998-2004

Area Description: This study took place in the Upper Green River Basin (UGRB) in southwestern Wyoming. The habitat within this area is currently considered as an internationally significant stronghold for greater sage-grouse. These birds rely on sagebrush habitats throughout all life stages.

Development: With the signing of the Record of Decision (ROD) in 2000, the Bureau of Land Management (BLM) approved the construction of 700 producing wells, 645 km of pipeline and 444 km of roads for the Pinedale Anticline Project Area. Additional wells (3,399) are currently being proposed. The ROD for the Jonah Infill Drilling Project was signed in March 2006, permitting year-round drilling of approximately 3,100 additional oil and gas wells to an existing 500. Maximum permitted total surface disturbance on the Jonah field is 14,030 acres.

Study Results: Results suggest that current natural gas development techniques have led to population declines. Impacts have been noted both on distribution and population levels - development has resulted in dispersal away from gas fields and lower survival rates.

• Among males, adult individuals were displaced from leks (a gathering place for males to display and attract females for breeding) and low recruitment was observed among juveniles. Male lek attendance also fell when traffic volumes on roads near leks increased.
• Leks within 3.9 miles of drilling, 3.8 miles of service roads, and 2.9 miles of producing wells had fewer males relative to leks farther from these facilities.
• Nesting females avoided areas with high densities of producing wells and brooding females avoided producing wells.
• Negative fitness consequences were also suggested for females that were subject to natural gas development during the breeding or nesting periods. While older females continued to return to their nesting areas, even following construction of roads and wells, yearling females left gas fields.
• There was a decline in the population of nesting females in developed areas, primarily due to lower survival, relative to females in undisturbed areas during the study.

Management Implications:

• Results predict sage-grouse populations will become extinct in the Pinedale Anticline and Jonah fields within 19 years if current population trends continue.
• Suggestions for reducing impacts include: sound muffling devices on noisy gas field structures, reducing overall traffic volumes and isolating the timing/location of traffic disturbance.
• In consideration of previous research across greater sage-grouse range, Holloran suggests protecting areas designated as suitable breeding habitats within 5 km of known leks from gas field development.
• Phased development of gas fields across the landscape and a refugia approach may allow for recolonization following field reclamation.
• In light of breeding population declines (17-49%) throughout its range in North America and recent petitions for listing under the Endangered Species Act, stipulations need to be modified to maintain populations within natural gas fields.