Consequences of Treating Wyoming Big Sagebrush to Enhance Wildlife Habitats

Abstract

Sagebrush (Artemisia L.) taxa historically functioned as the keystone species on 1 090 000 km2 of rangeland across the western United States, and Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle and Young) is or was dominant on a substantialamount of this landscape.Wyoming big sagebrush provides habitat for numerous wildlife species.Nevertheless,Wyoming big sagebrush communities are commonlymanipulated to decrease shrub cover and density and increase the productivity anddiversity of herbaceous plants.We examined relationships betweenmanagement-directed changes inWyoming big sagebrush and greater sagegrouse (Centrocercus urophasianus), elk (Cervus elaphus), pronghorn (Antilocapra americana), and mule deer (Odocoileus
hemionus), species commonly associated with these ecosystems.We focused on herbicide applications, mechanical treatments, and prescribed burning, because they are commonly applied to large areas in big sagebrush communities, often with the goal to improve wildlife habitats. Specifically, our objective was to identify treatments that either enhance or imperil sagebrush habitats for these wildlife species. The preponderance of literature indicates that habitat management programs that emphasize treatingWyoming big sagebrush are not supported with respect to positive responses by sage-grouse habitats or populations. There is less empirical information on ungulate habitat response toWyoming big sagebrush treatments, but the value of sagebrush as cover and food to these species is clearly documented. A few studies suggest small-scale treatments (60-m width) in mountain big sagebrush (Artemisiatridentata ssp. vaseyana [Rydb.] Beetle) may create attractive foraging conditions for brooding sage-grouse, but these may have little relevance toWyoming big sagebrush.Recommendations ormanagement programs thatemphasize treatments to reduceWyoming big sagebrush could lead to declines of wildlife species.More research is needed to evaluate the response of sagebrush wildlife habitats and populations to treatments, and until that time, managers should refrain fromapplying them inWyoming big sagebrush communities.