What is Palouse Prairie?
The Palouse Prairie is a bioregion in the Pacific Northwest that is defined by its land formations and soil types, rainfall and other climate features, and plant communities. Most maps of the Palouse Prairie place the bulk of the region in eastern Washington with additional areas along the western edge of north Idaho and in northeastern Oregon. This area is geographically bounded to the west and northwest by the scablands of central and northern Washington, to the east by the forests and foothills of Idaho’s Rocky Mountains, and to the south by the Snake and Clearwater rivers.
The Palouse Prairie isn’t flat, nor does it undulate gently. It has its own visually distinct rolling hills that were formed of wind-blown soil called loess. Wind deposition gave the hills their characteristic steep and rounded shapes. The soil layers can be over 100 feet deep in places, and their silty, loamy richness powers the agriculture in the region.
The Palouse Prairie region receives enough rain annually to support a profusion of native bunchgrasses (such as bluebunch wheatgrass and Idaho fescue) and wildflowers (such as arrowleaf balsamroot and prairie smoke), but not forests, generally, though the microclimate of a particular site dictates its plant communities. A drier south-facing hill might support native bunchgrasses but fewer flowers, while a wetter (snowier) north-facing slope might retain enough moisture to host a small stand of ponderosa pines, an island amid the prairie grasses and flowers. Before the agricultural boom of the 1880s, the native grasslands of the Palouse Prairie supported a rich diversity of grassland-adapted mammals, birds, reptiles and invertebrates, from deer and cougars to sharp-tailed grouse and giant Palouse earthworms.
By the turn of the 20th century, most of the original Palouse Prairie had been converted into farmland, and the region remains one of the most fertile, productive agricultural areas in the world, with large annual harvests of both legumes and grains. Iconic photographs of the Palouse today show ridgeline after ridgeline of low, sculpted hills colored with the rich greens, golds, and browns of wheat and barley, lentils and garbanzo beans. While little native Palouse Prairie remains, remnants can be seen at Kamiak Butte County Park, Steptoe Butte State Park, and The Nature Conservancy’s Rose Creek Preserve, all in eastern Washington.
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