Secretary of the Interior Ryan Zinke has ordered a review of greater sage conservation with an eye toward access for energy production. Greater sage grouse in Wyoming have been hurt by oil and gas drilling, and Wyoming's Gov. Matt Mead has warned Zinke against making big changes. (Tom Koerner/U.S. Fish and Wildlife Service)

A new federal study covering oil and natural gas development in Wyoming over a 25-year period found that as drilling density increased, the productivity of greater sage grouse breeding grounds consistently declined.

The conclusions in the latest peer-reviewed study — led by researchers at the U.S. Geological Survey and Colorado State University and published in The Journal of Wildlife Management — analyzed male attendance at grouse breeding grounds near drilling sites in Wyoming between 1984 and 2008. They found that male counts at these sites, called leks, decreased by 2.5 percent every year during the study period.

The decline in male attendance was “negatively related to oil and gas well density,” the 12-page study concludes. The low male attendance did not appear to be influenced by other factors including the height of sagebrush cover or precipitation patterns.

“Our results support those of other studies reporting negative impacts of oil and gas development on sage-grouse populations and our modeling approach allowed us to make inference to a longer time scale and larger spatial extent than in previous studies,” the study says.

What’s more, the study says that nearby oil and gas drilling “may also negatively affect other sagebrush-obligate species,” such as mule deer and elk, and that “active management of sagebrush habitats may be necessary to maintain some species.”

The link between drilling density and declining sage grouse populations is well-known. Oil and gas drilling, and the associated roads, pipelines and other infrastructure, have been shown in previous studies to drive away grouse.

See a collection of WyoFile reports on greater sage grouse

But the study appears to counter a detailed report released last summer by the Denver-based Western Energy Alliance and the Petroleum Association of Wyoming, which concluded that advances in horizontal drilling have significantly reduced the amount of surface acreage needed to tap oil and gas reserves in environmentally sensitive areas (EnergyWire, June 15).

The result, according to that report, is that sensitive species like greater sage grouse, mule deer, elk and pronghorn “can coexist with energy development,” and even thrive.

Kathleen Sgamma, the Western Energy Alliance’s vice president of government and public affairs, dismissed this new study, saying it is based on “old data” and “obsolete assumptions” about oil and gas development.

“The study ignores more recent information that shows surface disturbance has been dramatically reduced, by up to 70 percent, because of horizontal drilling and other industry innovation,” Sgamma said in an emailed statement to E&E News.

“The study suggests that at well densities over 10 wells per square mile there’s an impact on sage grouse, yet in 2016, industry practices combined with the state’s sage grouse plan mean that well pad densities are well below that number,” she added. “Other than for historical purposes, this study is largely irrelevant to what’s actually happening in Wyoming’s sage grouse habitat today.”

But Chris Saeger, director of the Western Values Project, said he disagrees.

Instead, Saeger said the study’s conclusions justify the oil and gas development protection measures included in the Interior Department’s sage grouse conservation plans, which call for guiding drilling away from sensitive grouse habitat.

The Western Energy Alliance and the North Dakota Petroleum Council earlier this year filed a federal lawsuit challenging the federal sage grouse plans as violating key federal laws (Greenwire, May 12).

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“The [federal] plans are designed to take new information on board, so the results of this study will only make this effort stronger,” Saeger said.

Thanks to the federal plans, he said, grouse habitat conditions have improved.

The latest report, he said, is a “reminder of how far we’ve come since 2008, when special interests dictated how our public lands should be used. Now, thanks to the plans and ongoing collaboration between federal and state agencies, sportsmen and others who care about our public lands, conditions are improving for sage grouse and the landscapes they inhabit.”

USGS and Colorado State University defended the study, saying the years of data collected and analyzed allowed the researchers to look at many aspects of oil and gas drilling on grouse, including the “delayed response” in some cases to nearby development.

“This approach allowed us to look at long time periods, including years before the oil and gas boom, which gave us a better picture of how sage-grouse have responded to oil and gas development,” Adam Green, lead author of the paper and a former CSU research scientist, said in a statement. “We found evidence of decreasing populations in response to increasing oil and gas development. This response was apparent as far as four miles from a lek, and the response was strongest four years following development.”

This detailed look at the responses of grouse over an extended period of time is relevant, in large part, because USGS says global energy demand is expected to increase “substantially in the next two decades, with fossil fuels accounting for more than one-third of that demand.”

The researchers found that sage grouse populations were stable when no wells were present near a lek, but “began declining with the addition of the first well,” according to a USGS summary of the study.

“Declines were not statistically significant until well density reached about 10.4 wells per square mile; however, at this well density, populations were predicted to decline 14 percent per year,” the summary says.

Read other recent stories about sage grouse in Wyoming

The study suggests that even well densities at one well per square mile within the boundaries of Wyoming’s designated core sage grouse areas “will likely result” in population declines.

“Energy development continues to affect important sagebrush habitat required by sage grouse and other species,” said Cameron Aldridge, an associate professor at CSU and one of the study’s authors. “This analysis provides new information to managers on how sage grouse populations respond to energy development, as they simultaneously work to implement conservation measures for sage grouse and meet demands for additional energy supplies.”


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  1. We seriously need to 0ut renewables on each home. NOT giant farms that disrupt nature and her denizens. But, as with most places, money wins out. WY doesn’t get any of that wind power. It all goes OUT of state. Not cool to destroy our places with any energy development and lie to us about it all. I am all for Responsible development of renewables and the stopping of fossils. Just on a scale that helps us and them.

  2. Anyone who suggests, or concludes, that the amount of sagebrush cover is not important to a study of rangeland disturbances upon Sage-grouse behavior is a bit suspect in my view. I encourage people to read this report, which is a study in statistics and assumptions (freely admitted) with some large gaps in data.

    One of the key conclusions is that projects with well densities of 10 wells per square mile show statistically significant impacts on Sage-grouse attendance at leks. There are not many currently active oil and gas drilling projects in eastern Wyoming which exhibit more than two drill sites (including multi-well drillsites) per one or two square miles.

    Perhaps the peer-reviewers double-checked the statistics, but maybe they should have given more attention to the assumptions. I am not sure that this report is valuable for future evaluations of oil and gas activity in the landscape.

    There are strong tendencies in these debates to vilify the “opposition”. I am not doing that, just asking some hard questions. If the BLM or the WOGCC are going to shut down valuable resource development in the name of preserving Sage-grouse, they should do so only when they are confident of the data supporting their decisions.

  3. Yesterday, I heard an NPR profile discussing Wyoming’s wind energy–the “clean” energy. The recent decision to avoid driving away companies that want to develop a “renewable” resource has now opened the way for companies to harness wind. A single company (I believe the reporter said it was New Zealand based) has a business plan that intends to put enough wind turbines on the landscape to cover an area of 190 square miles.
    Now–I know there are readers who are saying this response has nothing to do with sage grouse environment–because in all likelihood, these areas are not the same. What I do find perplexing is why the disturbance of landscapes for one creature is deserving of the critique from environmental protectionists but encouraging the development of a different type of energy production doesn’t receive the same degree of criticism? Wind energy will impact the landscape for many animals and birds–fly zones as well as the disturbance of the lands to build and maintain the turbines.
    Wyoming residents love the place they live. The majority of those who use the lands either recreationally or for business have done so with respect of both land and animals. Land owners of large swaths of sage grouse habitat have paid their dues by participating in projects that saved the habitat for sage grouse. It seems to me that this article wants to ignore the point that there are two sides to a discussion.
    One of the points that has been unstated is that most wild animals will cycle in numbers–increasing and waning. It happened that the assessments of impacts on oil/gas development coincided with the declines of sage grouse.
    I am proponent of responsible land use and applying the practices that enhance the overall condition of the landscape. In the end that works to the benefit of all who live there. Human beings LIVE in this state as well as the wildlife–and they are trying to survive here as well. It is incumbent on the part of policy makers to consider the needs of all. It is the responsibility of those providing information to the policy makers and the public to do so with a broader perspective included.