Sharp-tailed grouse in south-central Wyoming potentially a distinct subspecies

(Press-News.org) For decades, a population of grouse in south-central Wyoming and northwest Colorado has been identified as Columbian sharp-tailed grouse, the same subspecies that can be found in far western Wyoming near Jackson along with Idaho, northern Utah and parts of the Pacific Northwest.

But new research led by University of Wyoming scientists has found that the 8,000-10,000 sharp-tailed grouse found in the shrublands and high deserts of southern Carbon County and northwest Colorado are not Columbian sharp-tailed grouse. Nor are they more closely related to plains sharp-tailed grouse -- a subspecies found in portions of the northern Great Plains in the United States and Canada, including eastern Wyoming -- as was suggested by other researchers in 2006.

Rather, the birds potentially represent a distinct subspecies of sharp-tailed grouse that has been isolated from other populations of the bird for many years. The discovery could have major implications for wildlife managers in Wyoming and other states in the Intermountain West and Pacific Northwest.

“Our results may potentially change the current understanding of sharp-tailed grouse subspecies in western North America, which can impact how to manage them,” wrote the researchers, led by recent UW Ph.D. graduate Jonathan Lautenbach and Professor Jeff Beck, of UW’s Department of Ecosystem Science and Management. Their research appears in the journal Ecology and Evolution.

Currently, there are six recognized subspecies of sharp-tailed grouse in North America, generally separated geographically and by the habitats they occupy. They’re closely related to greater and lesser prairie chickens, which inhabit portions of the grasslands and shrublands of the Great Plains. In Wyoming, plains sharp-tailed grouse can be found in the grasslands of the eastern part of the state.

The sharp-tailed grouse found in Wyoming’s southern Carbon County and northwest Colorado -- which the UW researchers now suggest could be a distinct subspecies -- are isolated from the plains sharp-tailed grouse to the east, as well as from the Columbian sharp-tailed grouse farther west. But the isolated group has been categorized and managed as Columbian sharp-tailed grouse for many years.

The UW researchers used multiple lines of evidence to show that the south-central Wyoming sharp-tailed grouse are neither Columbian sharp-tailed grouse nor plains sharp-tailed grouse. They examined habitat characteristics, the birds’ appearance and two types of genetic data -- combined with computer modeling -- to reach their conclusion.

“Across all four datasets and both modeling techniques, we found that each population (Columbian, plains and south-central Wyoming sharp-tailed grouse) generally represented its own cluster,” the scientists wrote. “Our results suggest that the population of sharp-tailed grouse in south-central Wyoming is different from both Columbian and plains sharp-tailed grouse.”

Among the conservation and management implications of these new findings is a potential 10 percent to 20 percent decrease in the total number of birds recognized as Columbian sharp-tailed grouse, whose population has been estimated to be between 41,000-62,000 across multiple states and British Columbia. Due to habitat fragmentation and declining numbers, the Columbian sharp-tailed grouse has been petitioned for listing under the Endangered Species Act.

Additionally, the researchers say any efforts to boost Columbian sharp-tailed grouse numbers in states including Nevada, Oregon and Washington should not involve translocating sharp-tailed grouse from the isolated population of sharp-tailed grouse in south-central Wyoming and northwest Colorado. In addition to concerns about maintaining genetic integrity, the scientists note there are habitat differences between the two populations.

“Currently, habitat management actions are applied uniformly between Columbian sharp-tailed grouse and populations of sharp-tailed grouse in south-central Wyoming and northwest Colorado,” the researchers wrote. “Our results suggest a need to reevaluate habitat management approaches for sharp-tailed grouse across the range of these species/subspecies in Wyoming, Idaho and northwest Colorado.”

The research was funded, in part, by the Wyoming Game and Fish Department, the U.S. Forest Service, the Bureau of Land Management, the U.S. Department of Agriculture, the Wyoming Wildlife Federation and the High Plains Chapter of Pheasants Forever. Other members of the research team were from the University of North Texas, Boise State University, the Washington Department of Fish and Wildlife, and the George Miksch Sutton Avian Research Center in Bartlesville, Okla.

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