Wyoming, USA Photograph by USFWS   Western North America: Western United States Deserts and Xeric Shrublands   51,100 square miles (132,400 square kilometers) -- slightly larger than Alabama Vulnerable

· Three Rivers
· Special Features
· Did You Know?
· Wild Side
· Cause for Concern
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Three Rivers

The Green River, North Platte, and Wind-Bighorn River all drain this high, open countryside. Located in the rain shadow of the Rocky Mountains, the ecoregion receives little precipitation.

Special Features

Elevation, moisture levels, and amounts of snow and wind affect the patterns of where and what types of plants grow in this ecoregion. It is nearly surrounded by mountainous areas and because it is in the rain shadow of the Rocky Mountains, it receives very little precipitation.

Prairie dogs are important architects in this ecoregion. They live in groups in burrow complexes referred to as towns, which can be 10 feet (3 m) deep and cover thousands of acres. These towns provide habitat for many other animals, including coyotes and swift foxes. Pronghorns and bison are drawn to these sites because there are more plants to eat. The plants thrive due to the cultivation of the soil by the prairie dogs' diggings and the nutrients from their droppings.

Wild Side

Elk, mule deer, pronghorns, and prairie dogs are all herbivores that depend on the plants of this region. Their predators included raptors, coyotes, grizzly bears, and swift foxes. This was the home of the last known wild blackfooted ferrets, the most endangered mammals in the United States, and also was one of their first reintroduction sites after they became extinct in the wild. Sagebrush, wheatgrasses, and fescue are plants that you will find in the Wyoming Basin Shrub Steppe. Sagebrush dominates this area, partially because it adapts to drought conditions that kill most grasses.

Cause for Concern

Habitat loss due to degradation and conversion to crops is severe in some areas. But many areas of the ecoregion are remote from human population centers, so have been spared the impact of urban development so far. Grazing of domestic livestock and the spread of exotic grasses have altered natural habitat. Expansion of roads has fragmented habitat and allowed hunters much easier access to animals. Large-scale energy and mineral developments, such as oil and gas exploration and strip mining for coal, harm habitat and disturb herbivores. In the next 20 years, up to 11,000 new oil and gas wells could be sunk in southwestern Wyoming. This could have a severe negative long-term impact on the ecoregion.

For more information on this ecoregion, go to the World Wildlife Fund Scientific Report.