New wildlife studies cited recently by the Wyoming office of the Bureau of Land Management (BLM) conclude that current efforts to mitigate the impact of coalbed methane (CBM) development in the Powder River Basin (PRB) on the sage grouse and its habitat are not working and changes need to be made soon to avoid further loss of the bird population.

Release of the three peer-reviewed studies, performed by bioscientists at the University of Montana’s College of Forestry and Conservation, came on the heels of a sage grouse summit late last month in Casper, WY, led by Wyoming’s governor (see Daily GPI, July 5). The studies, performed by conservation scientists Brett L.Walker, David E. Naugle and Kevin E. Doherty, focus on sage grouse lek (mating ground) attendance, sage grouse use of winter habitat in areas of CBM development and the incidence of West Nile virus (WNv) in sage grouse populations.

The researchers studied sage grouse habitat, lek count and infrastructure data to assess how CBM development influenced trends in the numbers of male sage grouse observed and persistence of leks in the PRB. The PRB is the home to roughly 25% of the greater Wyoming Basin population of sage grouse, according to Walker.

The studies, which were funded by the oil and gas industry, the BLM and the state of Wyoming, indicate that in order to have a shot at preserving the species, a delicate dance will need to take place among energy producers, state and federal energy and wildlife agencies and the sage grouse.

Bob Bennett, state director of the Wyoming BLM, said “the results of these peer-reviewed studies will help inform management decisions in Wyoming in the months and years to come.” While not commenting on the results themselves, the announcement said “the BLM encourages anyone interested in sage grouse to familiarize themselves with the important research.”

The studies showed that “from 2000-2005, sage grouse populations in the PRB declined by 86% while populations outside of CBM development declined by 35%.” In addition, by 2005, leks in coalbed natural gas (CBNG) fields had 46% fewer males per active lek than leks outside of CBNG. The current 80- 160-acre spacing for CBM wells is three to six times greater than the level that sage grouse can tolerate, the reports said.

The studies conclude that current lease stipulations, which prohibit CBM development within 0.4 kilometers (km) of sage-grouse leks on federal lands, are “inadequate to ensure lek persistence and may result in impacts to breeding populations over larger areas.” Space accorded the leks preferably should be 6.2 km. The studies also noted that “seasonal restrictions on drilling and construction do not address impacts caused by loss of sagebrush and incursion of infrastructure that can affect populations over long periods of time.”

“The current pace and scale of CBNG development suggest that effective mitigation measures should be implemented quickly to prevent impacts from becoming more widespread,” the studies said. The scientists noted that previous studies of CBM development have recommended that “at minimum,” CBM developers should bury power lines; reduce the number of roads and well pads, industrial noise and vehicle traffic and manage CBM water to prevent the spread of mosquitoes that carry WNv in sage grouse habitat.

Walker told NGI that he has not seen any other peer-reviewed research that would contradict the findings of his group’s studies. He stressed that with the present stipulations “a tiny percentage of land is set aside for sage grouse if any. When you don’t set aside enough suitable habitat, it adds impact [to the species].”

With the release of these science-based reports, Wyoming Gov. Dave Freudenthal may be getting closer to knowing the “scientifically defensible estimates of the necessary habitat and sage grouse numbers to maintain the population,” which he called for at the close of the sage grouse summit. But the question still remains as to what is a desirable bird population relative to the human population’s need for energy.

“Everyone is asking us for the development threshold of what these birds will tolerate, but the real question that should be asked of the general public, regulatory agencies and state wildlife officials is ‘what population level [for the sage grouse] would you like?’ If everyone is OK with a reduced distribution [of sage grouse], then energy development that has impacts to sage grouse is going to be acceptable to everybody. This is the issue that is not being resolved,” Walker said.

BLM Director Bennett’s comments and a summary of the sage grouse reports are available at the BLM website, https://blm.gov/

The three sage grouse studies are available online, https://www.forestry.umt.edu.

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