Climate change may pose a substantial future risk for sagebrush habitat in southwestern Wyoming, and thus adversely affect the regional summer habitat and nesting areas of sage-grouse, according to a new study by the United States Geological Survey.
For the study, scientists used nearly 30 years of Earth observation data to analyze past climate patterns in 3,216 square miles (8,330square kilometers) of southwestern Wyoming to forecast sagebrush abundance in 2050. Wyoming is a stronghold for populations of greater sage-grouse, a species being considered for listing as threatened or endangered by the U.S. Fish and Wildlife Service. The species is dependent upon sagebrush habitat.
“Historic disturbances of fire, development and invasive species have altered the sagebrush landscape, but climate change may represent the habitat’s greatest future risk,” said Collin Homer, the USGS scientist who led the study. “Warming temperatures, combined with less snow and rain, will favor species other than sagebrush, as well as increase sagebrush habitat’s vulnerability to fire, insects, disease and invasive species.”
The authors noted that intact, healthy sagebrush systems increase sage-grouse resilience to negative effects of climate change whereas less intact and more marginal habitats decrease the species’ resilience.
Homer and his colleagues examined the impact of historical precipitation change on key components of sagebrush ecosystems from 1984 to 2011. These historical patterns, discerned from long-term records of the Landsat satellite series (a joint effort of USGS and NASA), were then combined with IPCC (Intergovernmental Panel on Climate Change) precipitation scenarios to model and forecast the most likely changes in sagebrush habitat from 2006 to 2050.
Researchers found that projected precipitation patterns for 2050 resulted in decreasing amounts of sagebrush and other shrubs, grasses, and flowering plants (forbs), while increasing the amount of bare ground. When these changes were translated to sage grouse habitat, researchers found this resulted in a potential loss of 12 percent of sage-grouse nesting habitat and about 4 percent of sage-grouse summer habitat by 2050. Results also demonstrate the vulnerability of semi-arid lands, such as sagebrush habitat, to precipitation changes because of their already low soil moisture content.
This new research explores how to bring climate change results to a more localized scale, in this case units as small as a quarter of an acre. “Using Landsat and downscaled climate scenarios to enable future forecasts of greater sage-grouse habitat can provide critical information on a more local or regional scale for managers to help them better plan now for the future,” said Homer.
Greater sage-grouse occur in parts of 11 U.S. states and two Canadian provinces in western North America. These birds rely on sagebrush ecosystems, which constitute the largest single North American shrub ecosystem and provide vital ecological, hydrological, biological, agricultural, and recreational ecosystem services. The U.S. Fish and Wildlife Service is formally reviewing the status of greater sage-grouse to determine if the species is warranted for listing under the Endangered Species Act.