Eliminating sagebrush may hurt rather than help wildlife
Efforts to enhance wildlife habitat by controlling vegetation could actually cause more harm than good. Wyoming big sagebrush is often manipulated to decrease its density and encourage the growth of herbaceous plants. However, this may bring about declines in the population of birds, elk, and other animals.
An article in the journal Rangeland Ecology and Management examines herbicide application, mechanical, and prescribed burning methods of controlling sagebrush and how they affect species such as greater sage-grouse, elk, pronghorn, and mule deer.
Sagebrush is a keystone species. It is often the most dominant vegetation in the vast areas of the western United States and is ecologically influential. Sagebrush offers thermal and security cover for animals. As forage, it is highly digestible and contains high levels of protein and other nutrients.
Land managers often seek to control sagebrush with the goal of improving wildlife habitat. The removal of sagebrush decreases shrub cover and density and allows increased productivity and diversity of herbaceous plants.
In the long term, however, this may have unintended negative consequences. Treatment can leave sagebrush plants of only a similar age. For a species known to live up to 216 years, this sacrifices structural diversity to support native fauna.
Treating sagebrush also can be beneficial or detrimental depending on the timing and extent of landscape cover. Many greater sage-grouse, elk, pronghorn, and mule deer migrate long distances seeking seasonal resources of sagebrush landscapes. Some treatments may be targeted specifically to one wildlife species, but may have undesired effects on other species.
The authors urge land managers to refrain from treating communities of Wyoming big sagebrush. They also encourage further research into how wildlife respond to the changes in habitat brought about by manipulating this shrub.
Full text of the article, "Consequences of Treating Wyoming Big Sagebrush to Enhance Wildlife Habitats," Rangeland Ecology and Management, Vol. 65, No. 5, 2012, is available at http://srmjournals.org/toc/rama/65/5.