BILLINGS, Mont. — A new study disputes a widely-held view that livestock grazing is largely incompatible with a ground-dwelling bird that has suffered a dramatic population decline across its 11-state range in the U.S. West.
Researchers said some grazing, particularly later in the growing season, could actually benefit the chicken-sized greater sage grouse.
Late-season grazing leaves in place for longer the grasses and other vegetation that sage grouse nest in, increasing their breeding success, researchers concluded. It also can stimulate the growth of vegetation that sage grouse eat, according to scientists from the U.S. Geological Survey, Colorado State University and Utah State University.
The study was published in the scientific journal Ecological Applications. It focused on more than 700 breeding sites for sage grouse in Wyoming, one of the bird’s last remaining strongholds.
An estimated 200,000 to 500,000 grouse remain in the U.S., down from a peak population of about 16 million.
Grazing on land occupied by greater sage grouse is frequently cited by biologists as one of the causes of the bird’s decline, along with disease, oil and gas drilling and other factors.
The latest findings don’t reject that claim outright, saying higher levels of grazing early in the growing season have been closely related to grouse population declines.
The new research could give land managers another tool to help assess grazing’s impacts on a local level, said Adrian Monroe, a research scientist at Colorado State and the study’s lead author.
“There could be benefits to both grouse and producers in terms of management,” Monroe said. “Up until now, we really lacked studies that directly linked the status and trends of sage grouse populations to management of livestock.”
Monroe added that the researchers’ conclusions were not meant to provide a “one-size fits all” approach. The work is most relevant to Wyoming, because that’s where the study was centred, and areas with similar arid landscapes in neighbouring states such as Colorado and Montana.
Jim Magagna with the Wyoming Stockgrowers Association welcomed the study’s conclusions. But he cautioned against using the findings to dictate where and when grazing can occur.
“I don’t think it lends itself to a simple formula saying, ‘This is the right way to graze,’ “ Magagna said.
The U.S. Interior Department in 2015 rejected federal protections for sage grouse, saying conservation efforts by government agencies and the private sector were helping turn around the bird’s declining fortunes.