Wyoming’s sage-grouse leks saw a 13% decrease in attendance during the spring mating season, according to the Wyoming Game and Fish Department (WGFD). The department counted just over 27,000 male sage-grouse, utilizing 91% of known, occupied leks. An average of 27 male sage-grouse were observed per active lek.

Natural Population Cycle

The natural population cycle of sage-grouse, along with habitat conditions, are thought to be responsible for the decline in lek attendance. Nearly 60 years of WGFD data on sage-grouse lek attendance displays the cyclical nature of sage-grouse population.

Studies indicate Wyoming’s sage-grouse population cycles every seven to nine years, said Nyssa Whitford, WGFD sage-grouse and sagebrush biologist. We were expecting to see a decrease this year as we enter the downward portion of the population cycle.

Whitford said that historical data indicates the downward trend in population can last about three to seven years. Though the cause of these population cycles is not entirely understood, WGFD believes that weather, climate, and availability of food and cover in the sagebrush ecosystem can play a role.

Other factors thought to influence the downward population trend include extreme drought, wildfire, and poor habitat quality. WGFD also stated that habitat fragmentation, short-term weather trends, and invasive grass negatively impact sagebrush habitat.

Sage-grouse are a sagebrush obligate species and could not survive without intact ecosystems, Whitford said. Well-timed moisture and available habitat are paramount to robust sage-grouse populations. In much of the state, this past winter was abnormally dry, and this summer has been exceptionally hot and dry.

Original reporting: Buckrail (Jackson WY) — read the source article.