Greater sage grouse numbers fell by more than half from 2007 to 2013 across the western United States, according to a newly released study by leading sage grouse scientists.
The study, commissioned by the Pew Charitable Trusts and shared exclusively with E&E Daily, comes months before the Obama administration must decide whether the chest-puffing bird deserves protections under the Endangered Species Act and as Republicans in Congress push legislation to delay those protections.
The research led by University of Idaho wildlife ecologist Edward Oz Garton is the most comprehensive study on sage grouse population trends since 2011, when Garton published a study on sage grouse numbers that was a major factor in the Fish and Wildlife Service’s decision to declare sage grouse a candidate species for protection.
"Our research should and must ring alarm bells," Garton said. "These numbers indicate to us that if significant protections aren’t established, this important bird and the entire sagebrush steppe region face irreparable harm."
Specifically, the study found that the number of breeding male grouse fell from 109,990 in 2007 to 48,641 in 2013. The data were collected at breeding grounds, known as leks, over several years and were submitted by state fish and game agencies in all 11 states where the grouse roam except Colorado.
The study considered 89,749 counts conducted by biologists and volunteers at 10,060 leks from 1965 through 2013.
Population numbers are not a key factor for whether a species is listed under ESA. But it’s unlikely that FWS will be able ignore Garton’s findings, especially since Garton’s early work was paramount in FWS’s finding in 2010 that sage grouse were on the path to extinction.
By court order, FWS must decide by Sept. 30 whether sage grouse are threatened or endangered.
Congress last December passed a spending bill barring FWS from writing a rule triggering actual federal protections, and two pieces of legislation introduced this week by Sen. Cory Gardner (R-Colo.) and Rep. Rob Bishop (R-Utah) would delay a listing and roll back federal sage grouse protection plans for up to a decade (E&ENews PM, April 22). Authors of those bills argue that efforts by states and landowners to proactively conserve sage grouse habitat could be undermined by a federal listing.
Garton’s study could also influence the Bureau of Land Management’s work to finalize land-use plans bolstering sage grouse protections across roughly 50 million acres of Western rangelands. BLM is being lobbied hard by conservationists, including Pew, as well as oil and gas companies, miners and ranchers. The final resource management plans (RMPs) are set to be released late next month.
The study paints a bleak picture about the species’ health.
"Clearly, more effort will be required to stabilize these declining populations and ensure their continued persistence in the face of ongoing development and habitat modification in the broad sagebrush region of western North America," said the study, which was co-authored by Jack Connelly, a retired scientist for Idaho’s Fish and Game Department, Adam Wells of Washington State University and Jeremy Baumgardt of Texas A&M University.
But study authors also noted that past research suggests sage grouse populations fluctuate on roughly decadelong cycles, and it is possible the bird is near the bottom of a population trough.
They noted that biologists in Idaho, Oregon, Nevada, Utah and Wyoming said 2013 was a particularly bad year for lek counts, coming after multiple years of drought and wildfires that can ruin the plants that sage grouse need for food and cover from predators.
"In 3-4 years these populations could increase again or the cycle may be disappearing and the precipitous drops since 2007 may be the start of a complete population collapse," the study said.
Ken Rait, director of U.S. public lands for Pew, said the report offers "definitive evidence about the fragile state of the greater sage-grouse" and is indicative of a troubling decline in the health of the sagebrush ecosystem, which is home to hundreds of other key species.
"We hope that this latest data will be used by the BLM and Western states to develop strong science-based land management plans that responsibly balance adequate protection of the sage-grouse and this important habitat with energy development and other land uses across the interior West," he said. "The Gardner and Bishop bills are a real threat to the bird, the sagebrush ecosystem and our Western way of life."
Garton will submit the study for peer-review publication in the coming weeks, but it may take several weeks or months before it is published. Pew has briefed state wildlife agencies and officials at FWS, BLM and the Forest Service of its findings.
An FWS official said the Garton report is one piece of evidence it will use in its September listing decision.
"Fish and Wildlife Service values all peer-reviewed scientific studies in helping us make the best regulatory and policy decisions," the official said. "The Garton study is one of several population trend analyses that will help us assess the health of the greater sage grouse and help inform our status review of the species."
State wildlife officials insist sage grouse numbers are on the upswing.
Tom Christiansen, sage grouse coordinator at Wyoming’s Game and Fish Department, said Garton’s study only looked at part of the sage grouse population cycle, which is "an inappropriate way to look at a population trend."
Wyoming biologists are nearing the end of 2015 lek counts, "and the reports I am receiving are very positive," he said. In fact, the areas he has personally counted are more than double last year’s count, he said, while cautioning that not all the data is in.
Sage grouse is a game bird subject to population swings of as much as 50 percent, Christiansen said. A Fish and Wildlife official said federal scientists believe there is a 30 to 40 percent swing.
Scientists should look at how past troughs and peaks compared to the most recent troughs and peaks, Christiansen said.
"There’s a long-term decline, there’s no denying that, from the 1950s to the present," he said. "But from the 1990s to present, that downward trend has not continued — it has leveled off."
Utah’s Division of Natural Resources in spring 2014 reported finding 4,449 male grouse in the Beehive State, an increase of almost 40 percent over the previous year.
Estimating actual sage grouse populations is a tricky task given that they inhabit some 165 million Western acres and the relatively reclusive hens exhibit "cryptic" behavior, FWS said in 2010. In contrast to males, which are relatively easy to count in springtime when they dance on leks to attract mates, scientists do not know how many hens are lurking in the brush.
Early reports suggested sage grouse once blackened the skies, with historical populations ranging from 1.6 million to 16 million birds. They declined in the 1920s and 1930s from overhunting and fell precipitously in the second half of the century due to habitat loss from wildfire, invasive species and energy development, among other threats. A 2004 study estimated that the bird had been extirpated from 44 percent of its historic range.
The study’s updated numbers "are bleak at this point," said Connelly, a co-author.
Major population drops occurred in the northern Great Basin, the Yellowstone River watershed in southeast Montana, the Powder River Basin in Wyoming, North Dakota and in Canadian border provinces, he said.
All hope is not lost, he said. It can take sage grouse populations years to respond to habitat disturbances like wildfire as well as improvements such as fence markings or the removal of harmful conifer trees, he said.
Researchers should revisit lek numbers each year, Connelly said.
"I’ve worked on the species for almost 40 years," he said. "I’d be a liar if I didn’t say I was deeply concerned."
Click here to read an executive summary of the study.
Click here to read the full study.