Publications

The North Cascades Ecoregion (Omernik, 1987; U.S. Environmental Protection Agency, 1997) covers approximately 30,421 km2 (11,746 mi2) of predominantly steep, mountainous terrain, home to peaks rising more than 3,000 m, which are carved by valleys that drop below 150 m elevation (fig. 1). The unique topography in this geographically isolated ecoregion has been shaped by glacial processes, and its d

The Willamette Valley Ecoregion (as defined by Omernik, 1987; U.S. Environmental Protection Agency, 1997) covers approximately 14,458 km² (5,582 mi2), making it one of the smallest ecoregions in the conterminous United States. The long, alluvial Willamette Valley, which stretches north to south more than 193 km and ranges from 32 to 64 km wide, is nestled between the sedimentary and metamorphic Co

Although global food production has been rising, the world sti ll faces a major food security challenge. Over one billion people are currently undernourished (Wheeler and Kay, 2010). By the 2050s, the human population is projected to grow to 9.1 billion. Over three-quarters of these people will be living in developing countries, in regions that already lack the capacity to feed their populations .

The Chihuahuan Desert is the largest of the North American deserts, extending from southern New Mexico and Texas deep into Mexico, with approximately 90 percent of its area falling south of the United States–Mexico border (Lowe, 1964, p. 24). The Chihuahuan Deserts Ecoregion covers approximately 174,472 km2 (67,364 mi2) within the United States, including much of west Texas, southern New Mexico, a

The Cascades Ecoregion (Omernik, 1987; U.S. Environmental Protection Agency, 1997) covers approximately 46,787 km2 (18,064 mi2) in Washington, Oregon, and California (fig. 1). The main body of the ecoregion extends from Snoqualmie Pass, Washington, in the north, to Hayden Mountain, near State Highway 66 in southern Oregon. Also included in the ecoregion is a small isolated section south of Bend, O

Located in eastern Washington and northern Oregon, the Columbia Plateau Ecoregion is characterized by sagebrush steppe and grasslands with extensive areas of dryland farming and irrigated agriculture. The ecoregion, which is approximately 90,059 km2 (34,772 mi2), is surrounded on all sides by mountainous ecoregions: to the west, the North Cascades Ecoregion and the Eastern Cascades Slopes and Foot

The Colorado Plateaus Ecoregion covers approximately 129,617 km2 (50,045 mi2) within southern and eastern Utah, western Colorado, and the extreme northern part of Arizona (fig. 1). The terrain of this ecoregion is characterized by broad plateaus, ancient volcanoes, and deeply dissected canyons (Booth and others, 1999; fig. 2). The ecoregion is bounded on the east by the Wyoming Basin and Southern

The Klamath Mountains Ecoregion covers approximately 47,791 km2 (18,452 mi2) of the Klamath and Siskiyou Mountains of northern California and southern Oregon (fig. 1) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion is flanked by the Coast Range Ecoregion to the west, the Southern and Central California Chaparral and Oak Woodlands Ecoregion to the south, the Cascades and

The Northern Basin and Range Ecoregion (Omernik, 1987; U.S. Environmental Protection Agency, 1997) is located in eastern Oregon (58.7 percent), northern Nevada (20.6 percent), southwestern Idaho (14.8 percent), and northeastern California (5.9 percent), encompassing the northern extent of the hydrographic Great Basin (Grayson, 1993). The ecoregion, which covers approximately 110,039 km² (42,486 mi

This chapter has been modified from original material published in Soulard (2006), entitled “Land-cover trends of the Central Basin and Range Ecoregion” (U.S. Geological Survey Scientific Investigations Report 2006–5288). The Central Basin and Range Ecoregion (Omernik, 1987; U.S. Environmental Protection Agency, 1997) encompasses approximately 343,169 km² (132,498 mi2) of land bordered on the west

The Puget Lowland Ecoregion covers an area of approximately 18,009 km² (6,953 mi²) within northwestern Washington (fig. 1) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion is located between the Coast Range Ecoregion to the west, which includes the Olympic Mountains, and the North Cascades and the Cascades Ecoregions to the east, which include the Cascade Range. From the

Located in south-central Idaho, the Snake River Basin Ecoregion spans 66,063 km2 (25,507 mi2) of mostly sagebrushsteppe (Artemisia tridentata) with some areas of saltbushgreasewood (Atriplex spp. and Sarcobatus spp.) and barren lava fields (fig. 1) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The Snake River is the dominant hydrographic feature extending the full length (east to we