Hells Canyon, eastern Oregon, USA Photograph by Daren H Spencer   Western North America: Western United States Temperate Grasslands, Savannas, and Shrublands   18,100 square miles (46,900 square kilometers) -- about the size of Vermont and New Hampshire combined Critical/Endangered

· What’s a Rain Shadow?
· Special Features
· Did You Know?
· Wild Side
· Cause for Concern
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What’s a Rain Shadow?

To the west of this ecoregion lies the Cascades Mountain range. As moist air from the Pacific Ocean blows east and rises over the mountains, it cools and drops rain or snow on the western slopes. By the time the air reaches the Palouse Grasslands ecoregion, it is dry, which creates this area's semiarid conditions.

Special Features

For thousands of years, Native Americans regularly set fires that helped the growth of the grasses. Currently, without frequent, low-intensity fires, dead plant material builds up and creates a large amount of "fuel." When a fire does occur, it burns so intensely that it can burn down to the soil.

	The Malheur shrew, a small mammal found in this ecoregion, is about the length of an adult finger.

Wild Side

In its prime, the Palouse Grasslands were a sea of bluebunch wheatgrass, Idaho fescue, bluegrass, needle-and-thread, and other grasses stretching to the horizon. It also contained shrubs, making it distinct from the shortgrass prairies nearby. Today, it is mostly made up of wheat fields and other exotic plant species.

Cause for Concern

Virtually all of the native grasses have been plowed away and replaced by crops such as wheat. Where grasslands remain, grazing livestock has overgrazed the native grasses and encouraged the invasion of cheatgrass and other exotic species. Because of the transformation of natural habitat to mostly agricultural use, 99 percent of the original habitat is gone.

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