Publications

Summary U.S. Geological Survey (USGS) Professional Paper 1794 is a four-volume series on the status and trends of the Nation’s land use and land cover, providing an assessment of the rates and causes of land-use and land-cover change in the United States between 1973 and 2000. Volumes A, B, C, and D provide analyses for the Western United States, the Great Plains, the Midwest–South Central United

Preface U.S. Geological Survey (USGS) Professional Paper 1794–A is the first in a four-volume series on the status and trends of the Nation’s land use and land cover, providing an assessment of the rates and causes of land-use and land-cover change in the Western United States between 1973 and 2000. Volumes B, C, and D provide similar analyses for the Great Plains, the Midwest–South Central United

The Sonoran Basin and Range Ecoregion covers approximately 116,364 km2 (44,928 mi2) of desert landscape in southeastern California and southwestern Arizona (fig. 1) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). This ecoregion is bounded on the west by the Southern and Central California Chaparral and Oak Woodlands and the Southern California Mountains Ecoregions; on the north by the

This chapter has been modified from original material published in Sleeter and Raumann (2006), entitled “Land-cover trends in the Mojave Basin and Range Ecoregion” (U.S. Geological Survey Scientific Investigations Report 2006–5098). The Mojave Basin and Range Ecoregion (Omernik, 1987; U.S. Environmental Protection Agency, 1997) covers approximately 130,922 km2 (50,549 mi2) in the southwestern Unit

The Madrean Archipelago Ecoregion (Omernik, 1987; U.S. Environmental Protection Agency, 1997), also known as the “Madrean Sky Islands” or “Sky Islands,” covers an area of approximately 40,536 km2 (15,651 mi2) in southeastern Arizona and southwestern New Mexico (fig. 1). The ecoregion is bounded on the west by the Sonoran Basin and Range Ecoregion, on the east by the Chihuahuan Deserts Ecoregion, a

Situated between ecoregions of distinctly different topographies and climates, the Arizona/New Mexico Plateau Ecoregion represents a large area of approximately 192,869 km2 (74,467 mi2) that stretches across northern Arizona, central and northwestern New Mexico, and parts of southwestern Colorado; in addition, a small part extends into southeastern Nevada (fig. 1) (Omernik, 1987; U.S. Environmenta

The Wyoming Basin Ecoregion (Omernik 1987; U.S. Environmental Protection Agency, 1999) covers approximately 128,914 km2 (49,774 mi2) in Wyoming and parts of northwestern Colorado, northeastern Utah, southeastern Idaho, and southern Montana (fig. 1). The ecoregion is bounded on the east by the Northwestern Great Plains Ecoregion; on the south and east by the Southern Rockies Ecoregion; on the south

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

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 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

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 Southern and Central California Chaparral and Oak Woodlands Ecoregion, which covers approximately 102,110 km2 (39,425 mi2), is characterized by a Mediterranean climate with cool, moist winters and hot, dry summers (Omernik, 1987; U.S. Environmental Protection Agency, 1997). Natural vegetation includes chaparral (for example, manzanita, Arctostaphylos spp.) and oak (Quercus spp.) woodlands with