Chihuahuan Desert Mojave Desert Great Basin Desert Sonoran Desert United States Four Major Desserts
Chihuahuan Desert Chihuahuan Desert is the largest desert in North America covering more than 200,000 square miles -- Most of it lies south of the international border. In the U.S. it extends into parts of New Mexico, Texas and sections of southeastern Arizona. Its minimum elevation is above 1,000 feet, but the vast majority of this desert lies at elevations between 3,500 and 5,000 feet.
Winter temperatures are cool, and summer temperatures are extremely hot. Most of the area receives less than 10 inches of rainfall yearly. While some winter rain falls, most precipitation occurs during the summer months. This desert covers such a large area that it is difficult to characterize its geology, but limestone and calcareous soils are common.
Like the Great Basin Desert, this is a shrub desert, but the biological diversity of perennial plant life is relatively low. Yuccas and agaves, growing with grasses and often Creosote Bushes, give this desert its characteristic appearance. Prickly-pears and Mormon Tea are also contribute prevalent. Tarbush is sometimes a dominant shrub. Honey Mesquite grows along washes and playas. White-thorn Acacia, Allthorn and Ocotillo are other large, conspicuous plants of the Chihuahuan Desert.
Approximate Desert USA Boundaries: Bordered on the west by Arizona's U.S. Route 191, on the north by Interstate 40, on the east by Texas' U.S. Route 385, and south to the Mexican border.
Mexican Wolf Some Mexican Gray Wolves are still in the Chihuahuan Desert
Great Basin Desert The Great Basin Desert, the largest U. S. desert, covers an arid expanse of about 190,000 square miles and is bordered by the Sierra Nevada Range on the west and the Rocky Mountains on the east, the Columbia Plateau to the north and the Mojave and Sonoran deserts to the south.
This is a cool or "cold desert" due to its more northern latitude, as well as higher elevations (at least 3,000 feet, but more commonly from 4,000 to 6,500 feet). Precipitation, generally 7-12 inches annually, is more evenly distributed throughout the year than in the other three North American deserts. Winter precipitation often falls as snow.
Playas are a conspicuous part of this desert, due to its recent geological activity. These are small towns built by businesses.
In notable contrast to the other three deserts, Great Basin vegetation is low and homogeneous, often with a single dominant species of bush for miles. Typical shrubs are Big Sagebrush, Blackbrush, Shadscale, Mormon-tea and greasewood. There are only occasional yuccas and very few cactus.
The Colorado Plateau, centered in northeastern Arizona, and including the adjacent Four Corners region of Utah, Colorado and New Mexico, is sometimes included in the Great Basin Desert, sometimes considered a separate desert
-- the Navajoan -- and sometimes not considered a true desert. The Plateau includes large barren areas, spectacular geological formations, more juniper and pinyon trees and generally higher elevations.
Mojave Desert The transition from the hot Sonoran Desert to the cooler and higher Great Basin is called the Mojave Desert. This arid region of southeastern California and portions of Nevada, Arizona and Utah, occupies more than 25,000 square miles.
Situated between the Great Basin Desert to the north and the Sonoran to the south (mainly between 34 and 38°N latitudes), the Mojave, a rainshadow desert, is defined by a combination of latitude, elevation, geology, and indicator plants. Elevations are generally between three and six thousand feet, although Death Valley National Park includes both 11,049-foot Telescope Peak and the lowest point in the United States 282 feet below sea level at Badwater.
Temperatures are a function of both latitude and altitude. Although the Mojave Desert has the lowest absolute elevation and the highest maximum temperature (134°F in Death Valley), it is north of the Sonoran Desert and its average elevations are higher. As a result, its average temperatures are lower than those of the Sonoran.
The Mojave has a typical mountain-and-basin topography with sparse vegetation. Sand and gravel basins drain to central salt flats from which borax, potash and salt are extracted. Silver, tungsten, gold and iron deposits are worked.
While some do not consider the Mojave a desert in its own right, the Mojave Desert hosts about 200 endemic plant species found in neither of the adjacent deserts. Cactus are usually restricted to the coarse soils of bajadas. Mojave Yucca and, at higher elevations Desert Spanish Bayonet, a narrow-leafed yucca, are prominent. Creosote Bush, Shadscale, Big Sagebrush, Bladder-sage, bursages and Blackbush are common shrubs of the Mojave Desert.
Occasional Catclaws grow along arroyos. But, unlike the Sonoran Desert, trees are few, both in numbers and diversity. The exception is the Joshua-tree. While this unusual tree-like yucca is usually considered the prime indicator of Mojave Desert vegetation, it occurs only at higher elevations in this desert and only in this desert.
Sonoran desert The Sonoran Desert is an arid region covering 120,000 square miles in southwestern Arizona and southeastern California, as well as most of Baja California and the western half of the state of Sonora, Mexico. Subdivisions of this hot, dry region include the Colorado and Yuma deserts. Irrigation has produced many fertile agricultural areas, including the Coachella and Imperial valleys of California. Warm winters attract tourists to Sonora Desert resorts in Palm Springs, California, and Tucson and Phoenix, Arizona.
This is the hottest of our North American deserts, but a distinctly bimodal rainfall pattern produces a high biological diversity. Winter storms from the Pacific nourish many West Coast annuals such as poppies and lupines, while well-developed summer monsoons host both annuals and woody plants originating from the south. Freezing conditions can be expected for a few nights in winter.
Trees are usually well developed on the desert ranges and their bajadas. Often abundant on these well-drained soils are Little-leaf Palo Verdes, Desert Ironwoods, Catclaw and Saguaro.
The understory consists of three, four or even five layers of smaller woody shrubs. Tall chollas may occur in an almost bewildering array of species. The alluvial lowlands host communities of Desert Saltbush, wolfberry and bursage. On coarser soils, Creosote Bush and bursage communities may stretch for miles. Where the water table is high, Honey or Velvet Mesquite may form dense bosques or woodlands.
Other species are restricted to alkaline areas. Stream sides may be lined with riparian woodlands composed of Arizona Ash, Arizona Black Walnut, Fremont Cottonwood and various willows, with a dense understory of Arrow-weed, Seepwillow and Carrizo. The Sonora Desert is rich in animal life as well, with many species in all groups derived from tropical and subtropical regions.
The western part of the Sonora Desert (sometimes called the "Colorado Desert") is closer to the source of Pacific storms and is noted for spectacular spring flowering of ephemerals when there is winter-spring rainfall. (This phenomenon is not limited to here.) However, the western portion is relatively depauperate, lacking many of the species such as the Saguaro that depend on good summer rainfall.
Approximate DesertUSA Boundaries: Bordered on the west by Borrego Springs, and San Gorgonio Pass in southern California, on the north by Interstate 10 in California and Interstate 40 in Arizona, on the east by Arizona's U.S. Route 191, south to the tip of Baja California, Mexico.