Sagebrush Steppe

American badgers are common in the sagebrush steppe

Plant species include Wyoming and low sagebrush, bluebunch wheatgrass, Sandberg’s bluegrass, bottlebrush squirreltail, Idaho fescue, needle-and-thread, Thurber’s needlegrass, western yarrow, arrowleaf balsamroot, and various locoweed and phlox species. A gradient in soil depth determines whether Wyoming big sagebrush or low sagebrush dominates a site. Low sagebrush sites typically host higher densities of forbs due to higher concentrations of available soil moisture due to shallow, rocky conditions. These communities depend on natural fire cycles or equivalent disturbance to maintain a balance between shrub, grass, and forb components. A lack of disturbance lends itself to high shrub densities with sparse vegetation in the interspaces.

Examples of obligate shrub-steppe species include sagegrouse, Brewer’s sparrow, sage sparrow, and sage thrasher. Likely because of the elevation, condition and fragmentation of refuge shrub-steppe, only very limited use by sagegrouse has been observed on the Refuge.

Historically the area also supported sharp-tailed grouse, which were last documented in southeastern Oregon in 1940. Many other birds occur in shrub-steppe but are not as dependent on sagebrush. Examples of these include burrowing owl, lark sparrow, vesper sparrow, horned lark, loggerhead shrike, long-billed curlew, and western meadowlark.

Mule deer, pronghorn, and occasionally elk use these areas, which are within their winter range. Coyotes, bobcats, and badgers are common in these areas, and mountain lions are rarer, but present. The black-tailed jackrabbit, Nuttall’s cottontail, least chipmunk, Townsend’s and golden-mantled ground squirrels, and northern and Townsend’s pocket gophers are locally abundant in shrub step.

A variety of reptiles use shrub-steppe habitat, including sagebrush, fence and side-blotched lizards; western rattlesnakes; racers; gopher snakes; and common garter snakes. Amphibians are represented by spade-foot toads.

Originally, upland habitats were composed of native shrubs, bunchgrasses, and forbs. Most of the former native vegetation has been severely altered by historical land use, including intensive livestock grazing, reduced burning frequency, and cultivation. Large areas of shrub-steppe have been seeded to crested wheatgrass or as part of former “fire restoration” activities.

Invasive plants, such as medusahead and cheatgrass, are major threats to the remaining shrub-steppe areas of the Refuge. Medusahead is capable of outcompeting native grasses and forbs in the understory. An altered fire regime resulting in more frequent fire return intervals due to the volatility of cheatgrass can limit recovery of sagebrush species in these communities, and wildfire can exacerbate these invasions.

To provide green winter browse for wintering Canada geese, crested wheatgrass seedings have been treated with livestock grazing to provide short stubble. Otherwise, cattle have been excluded from most of these sites on the Refuge. Research on restoring crested wheatgrass areas to more native shrub-steppe communities is being conducted in conjunction with the Eastern Oregon Agricultural Research Center (USDA Agricultural Research Service).