|Sage hen on the Yakima Training Center|
The greater sage-grouse (Centrocercus urophasianus) are a large ground dwelling bird, in fact the largest of the grouse species, that were once prolific through regions where sagebrush (Artemisia tridentata) was the dominant vegetation. They depend on these large woody sagebrushes during all parts of the year for survival. Because of this, they are considered a sagebrush obligate species. However, this is an ecosystem at risk due to many anthropogenic disturbances. Much of the sagebrush has been removed, plowed under, and converted to agricultural lands suited for crops and livestock. Expanding urban populations are also decimating and fragmenting the sagebrush habitat. Changes from frequent, low intensity fires to less frequent, but high intensity fires that remove all vegetation have also contributed to the loss of sage grouse habitat. Overgrazing of livestock may also be a factor that has contributed to the decline of sage grouse in the last century.
The greater sage grouse is largely dependent on sagebrush and accompanying herbaceous cover. Unless action is taken to conserve and preserve this vast, injured ecosystem, the sage grouse will be extirpated from North America. Recently, this unique species of grouse has become a species of concern for land management agencies such as the Bureau of Land Management, Fish and Wildlife, and Department of Natural Resources.
In March 2010, the United States Fish and Wildlife Service declared that federal listing of sage-grouse under the Endangered Species Act (ESA) is warranted, however there are other species facing a greater threat of extinction. Therefore, sage-grouse are on the long list of potential candidates, waiting for their ESA bodyguard. Despite this, management practices are being implemented nationwide to protect them and their declining habitat. This is a critical step to prevent further population declines. The focus of this thesis will study how local grazing regimes and coordinated management are being used to protect sage grouse habitat on the Wild Horse Wind Farm in Ellensburg, Washington.
Historically, sage-grouse covered much of sage-brush land in Eastern Washington. Since the 1800's, their populations have declined due to loss of habitat, as mentioned, and also unrestricted hunting (Hays et al, 1998). As a result, they are now limited to two populations in what was once an extensive range (Figure 1). One is on the Yakima Training Center (YTC) and the other is on sections of private property in Douglas County where Conservation Reserve Programs (CRP) have allowed habitat to remain intact. The study area, located on the Wild Horse Wind Facility east of Ellensburg, Washington and between these two geographic locations, is at the western edge of the Colockum Wildlife Area. It is needed to provide connectivity between these two isolated populations of sage-grouse. This study will help with these efforts to provide sage-grouse habitat between these two populations.