What is shrub-steppe?
Shrub-steppe is the largest natural grassland in North America. It extends from southeastern Washington and eastern Oregon, through Idaho, Nevada, and Utah, and into western Wyoming and Colorado. Shrub refers to the most abundant plant species that grows in this ecoregion. "Steppe" is a Russian word that means a vast treeless plain. In the Mid-Columbia Basin, shrub-steppe winters are cold and wet with strong winds and blowing snow. Summers are hot and dry with temperatures that can reach above 100 degrees Fahrenheit during the day, then cool at night. Here, less than 7 inches of rain falls per year.
What plants are common in the shrub-steppe?
The kind of plants that grow in a region is determined by many things, including climate and soil, geology and topography. Under natural conditions, shrub-steppe lands are covered with grasses and shrubs. The most common shrub, or woody plant, is big sagebrush. Other shrubs you probably have seen in our area, but may not have recognized, are rabbitbrush, greasewood, hopsage, bitterbrush, and buckwheat. They grow in communities with grasses such as bluebunch wheatgrass and Sandberg's bluegrass.
How do you tell the shrubs apart?
Rabbitbrush often is mistaken for sagebrush because both shrubs are medium sized, gray-green, frequently grow together, and bloom in late summer or fall. One way you can distinguish between them is to sniff a leaf. Rabbitbrush doesn't smell as strong as sage, and it has long, unlobed leaves. Sagebrush has three lobes at the tip each leaf. Also, rabbitbrush has large bright yellow flowers, while the flowers of sagebrush are tiny and inconspicuous.
Although identifying shrubs may seem confusing, you probably are familiar with some shrub-steppe wildflowers. Likely you have seen the bright yellow flowers and heart-shaped leaves of Carey's balsamroot covering Mid-Columbia hillsides in spring, along with rich displays of purple-blue lupine. In sandy areas, you also may have seen longleaf phlox climbing up through the branches of sagebrush.
What wildlife species are common in the shrub-steppe?
The shrub-steppe ecoregion supports a variety of birds, mammals, and reptiles/amphibians. More than 200 bird species and 30 kinds of mammals are known to live in our arid region. The types of plants that grow in the shrub-steppe determine the number and kinds of wildlife that can live here too. Wildlife depend on plants for food, concealment, protective cover, and for some species of birds, for nesting.
Some breeding birds that live in the Mid-Columbia are chukar, common ravens, black-billed magpies, Swainson's hawks, red-tailed hawks, horned larks, western meadowlarks, and burrowing owls. Mammals that make their home here include such species as elk, mule deer, bobcat, and black-tailed jackrabbit. The Great Basin pocket mouse and Townsend's ground squirrel also live here. These small mammals provide a source of food for badgers, coyotes, and nesting hawks. Less common in our area are reptiles and amphibians, though we do have side-blotched lizards and northern Pacific Rattlesnakes. Great Basin spadefoot toads have been seen near Rattlesnake Springs in the Rattlesnake Hills.
What is the future of shrub-steppe?
Until 100 years ago, shrub-steppe vegetation covered more than 200,000 square miles of the American West but, as a result of expanded human development, much native vegetation has been eliminated or fragmented, or the kind of plants has been altered by the invasion of non-native species such as cheatgrass, which European settlers accidentally introduced to our region. Although change is a natural part of landscapes, such a rapid change severely affected native wildlife of the region. Because so much of the shrub-steppe was converted to farmland and homesteads, soil erosion increased sharply, not only eroding the soil, but covering the land with blowing dust and increasing the amount of silt in local waters. Many animal habitats were reduced or eliminated.
