Greater sage-grouse as an umbrella species for sagebrush-associated vertebrates.

摘要

Widespread degradation of the sagebrush ecosystem in the western United States, including the invasion of cheatgrass, has prompted resource managers to consider a variety of approaches to restore and conserve habitats for sagebrush-associated species. One such approach involves the use of greater sage-grouse, a species of prominent conservation interest, as an umbrella species. This shortcut approach assumes that managing habitats to conserve sage-grouse will simultaneously benefit other species of conservation concern. The efficacy of using sage-grouse as an umbrella species for conservation management, however, has not been fully evaluated. We tested that concept by comparing: (1) commonality in land-cover associations, and (2) spatial overlap in habitats between sage-grouse and 39 other sagebrush-associated vertebrate species of conservation concern in the Great Basin ecoregion. Overlap in species' land-cover associations with those of sage-grouse, based on the phi (phi) correlation coefficient, was substantially greater for sagebrush obligates (x=0.40) than non-obligates (x=0.21). Spatial overlap between habitats of target species and those associated with sage-grouse was low (mean phi =0.23), but somewhat greater for habitats at high risk of displacement by cheatgrass (mean phi =0.33). Based on our criteria, management of sage-grouse habitats likely would offer relatively high conservation coverage for sagebrush obligates such as pygmy rabbit (mean phi =0.84), but far less for other species we addressed, such as lark sparrow (mean phi =0.09), largely due to lack of commonality in land-cover affinity and geographic ranges of these species and sage-grouse..