Current wildfire trends could cut sage grouse populations dramatically
Slowing the spiral of growing wildfires may be crucial to protecting greater sage-grouse during the next 30 years, U.S. Geological Survey researchers said after comparing wildfire, precipitation and sage grouse population trends.
Cutting destructive fires near key habitat areas would be most beneficial and could even help sage grouse populations rebound, the scientists concluded.
The new study projects that, if the current trend in wildfire continues unabated, sage grouse populations will continue to plummet — by as much as half by the mid-1940s. The models used by the scientists simulated different post-fire recovery times for sagebrush habitats based on soil attributes — soil moisture and temperature maps — that strongly influence resilience to wildfire and resistance to invasive grass species.
The findings also showed that greater sage-grouse populations increase following periods of above-average precipitation. But the long-lasting effects of wildfire in greater sage-grouse breeding areas negated the positive effects associated with precipitation.
Climate change may result in less precipitation and warmer, drier soils in sagebrush ecosystems, leaving greater sage-grouse habitat vulnerable to increasingly frequent wildfires. Fire is a natural process in sagebrush ecosystems, but burn size and frequency in the Great Basin have increased over the past few decades in response to the increasing expansion of invasive grasses, primarily cheatgrass.
Wildfires kill nearly all native species of sagebrush, which can transform the habitat into landscapes dominated by invasive grasses when soils are warm and dry. In turn, the presence of invasive grasses can prevent sagebrush from returning and, by serving as tinder, result in a positive feedback loop that promotes more wildfires in future years.
“Greater sage-grouse population persistence may be compromised as sagebrush ecosystems and sage-grouse habitat become more impacted by fire and a changing climate,” said Peter Coates, a research scientist with the USGS Western Ecological Research Center. “Our research shows that targeted fire suppression in core sage-grouse areas is vital to help conserve large blocks of the best habitat for sage-grouse in the Great Basin,” Coates said.
Specifically, the study found that reducing the trend in annual cumulative burned area near leks sites by 75 percent would help slow greater sage-grouse population declines, even during periods of below-average precipitation.
Coates said more long-term research can help identify populations that are most at risk from wildfire or changing climate and lead to more effective targeting of management resources for conservation of sagebrush and greater sage-grouse populations.
This peer-reviewed research, Long-term effects of wildfire on sage-grouse populations: an integration of population and ecosystem ecology for management in the Great Basin, was authored by Peter Coates, USGS; M.A. Ricca, USGS; B.G. Prochazka, USGS; , K.E. Doherty, USFWS; M.L. Brooks, USGS; and M.L. Casazza, USGS.