Study addresses impact of loss of sagebrush habitat on wildlife
“One of the most tragic examples of our unthinking bludgeoning of the landscape is to be seen in the sage-brush lands of the West, where a vast campaign is on to destroy the sage and substitute grasslands.”
— Rachel Carson, “Silent Spring,” 1962
Today, there is widespread concern over the continued loss of sagebrush habitat across the West.
Not only is the landscape changed, but familiar species disappear, and in some ways traditional activities also are threatened.
While sage grouse seem to get most of the publicity, there are many other species threatened by the continued loss of sagebrush habitat.
A report prepared by two western Colorado biologists addressing the impacts of sagebrush loss is being considered for adoption by the Colorado Wildlife Commission.
While the conservation strategies outlined in the report have not been formally adopted by the Division of Wildlife, the study was done to provide information and guidelines for the division in its conservation strategies for certain species of concern and sagebrush habitat.
The authors of the reports were Stephen A. Boyle, a senior biologist with BIO-Logic Environmental of Montrose, and Dawn R. Reeder, a biologist with Rare Earth Science LLC of Grand Junction and Paonia.
The report focused on sagebrush-dominated landscapes across 39 counties in central and western Colorado. Sagebrush is found on more than 5.43 million acres in those areas. Much of that sagebrush is variously threatened by pinyon-juniper encroachment, weed encroachment, and energy or residential development, the study says.
The study says just over half of all sagebrush-dominated areas are concentrated in northwestern Colorado, North Park-Middle Park and the Gunnison Basin.
While these areas should be considered “cornerstones of sagebrush conservation,” the study pointed out that smaller and scattered sagebrush areas also provide important “landscape linkages.” These linkages are vital for supporting species and certain ecosystem functions.
Other points the study reported include:
At least 13 percent of sagebrush shrublands in the assessment area has been lost to land-use conversions, primarily agriculture, since pre-Euro-American settlement times.
About 44 percent of the sagebrush-dominated landscapes are on private lands, 41 percent on Bureau of Land Management lands and 7 percent on Forest Service lands.
The study addressed impacts of sagebrush loss on 11 species of concern: black-throated sparrow, Brewer’s sparrow, green-tailed towhee, kit fox, lark sparrow, Merriam’s shrew, northern harrier, sage sparrow, sage thrasher, sagebrush vole and vesper sparrow.
The Greater sage grouse and the Gunnison sage grouse were not addressed in this study per direction of the Division of Wildife, which already has separate conservation studies for those two species.
Losing their native habitat is the “most-serious consequence” of sagebrush conversion.
Almost 4.46 million acres (81 percent) of sagebrush are under a moderate or high risk of all threats combined.
“It’s recognized that an awful lot of our challenges with wildlife are habitat-related,” Boyle said. “If we can just protect enough habitat, we can keep the wildlife as abundant as we want.”
The complete report may be viewed on the Division of Wildlife website, wildlife.state.co.us. Click on wildlife commission, then “Colorado sage-grouse conservation.”