SNAKE RIVER PLAIN: Burley, ID to Farewell Bend, OR
Location: Located primarily in southern Idaho and extending a short distance into Oregon near Ontario. The plains and low hills are located in the dry, wide valleys found between mountain ranges. Many of the valleys along the Snake River in Idaho are in agriculture. In Oregon, valleys are covered by sagebrush-grassland and is used for cattle grazing.
Climate: The ecoregion has a dry, mid-latitude steppe climate, marked by warm summers and cold winters. The mean annual temperature is approximately 10°C in the west and 6°C in the eastern portion. The frost-free period ranges widely from 50 to 170 days, decreasing from west to east and with elevation. The mean annual precipitation is 316 mm, ranging from 110 to about 650 mm.
Vegetation: Sagebrush steppe natural vegetation with Wyoming and basin big sagebrush, mountain sagebrush, bluebunch wheatgrass, Idaho fescue, Indian ricegrass, rabbitbrush, fourwing saltbush.
Hydrology: The Snake River flows through the region. Surface waters are sparse in a few parts. Streams are generally lower gradient, warmer, with finer substrates than in adjacent mountain ecoregions. Canals and reservoirs are common in and near agricultural areas. Springs occur in some areas.
Terrain: The terrain is lower and more gently sloping than the surrounding ecoregions, and consists of alluvial valleys, scattered barren lava fields, plains, and low hills. Elevations range from 640 to about 1,980 masl, with the eastern portion being higher. Most of the region contains nearly horizontal sheets of basalt. Older flows are of Miocene and Pliocene age, while large areas consist of Quaternary basalt. Soils are mostly Aridisols and Mollisols and have mesic and some frigid temperature regimes and aridic and xeric moisture regimes.
Wildlife: Historically, the region had bison, bighorn sheep, grizzly bear, gray wolf. Today, one finds Rocky Mountain elk, mule deer, pronghorn, black bear, coyote, cougar, bobcat, yellow pine chipmunk, Great Basin pocket mouse, dark phase pika, migratory waterfowl, prairie falcon, ravens, sage thrasher, mountain chickadee, mountain bluebird, bats, rainbow, brown and brook trout.
Photos of birds observed on our road-trip.
Land Use/Human Activities: Mostly because of the amount of water available for irrigation, a large percent of the alluvial valleys bordering the Snake River are in agriculture, with sugar beets, potatoes, alfalfa, small grains, and vegetables being the principal crops. Cattle feedlots and dairy operations are also common in the river plain. Other areas of the ecoregion are used as rangeland for cattle grazing. Large cities include Boise, Nampa, Pocatello, Idaho Falls, and Twin Falls.
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Commission for Environmental Cooperation; North American Terrestrial Ecoregions—Level III; April 2011.
Photos taken in October 2013 along highways-
Just Another Nature Enthusiast Photography byJane Wilson is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.