Basin and Range - Chihuahuan Desert

southern New Mexico, western Texas

Land-Surface Form

This area is mostly desert and has undulating plains with elevations near 4,000 ft (1,200 m), from which somewhat isolated mountains rise 2,000 to 5,000 ft (600 to 1,500 m). Washes, dry most of the year, fill with water following rains. Small whirlwinds constantly play over these dry playas when they are heated by summer sun. Extensive dunes of silica sand cover parts of the area; in a few places, there are dunes of gypsum sand, the most notable being the White Sands in southern New Mexico. The Rio Grande and Pecos Rivers flow through the region.

Aquatic Resources

The major rivers found in the Chihuahuan Desert include the lower two thirds and mouth of the Pecos River, the lower half and mouth of the Rio Grande River, the headwaters and majority of the Gila River, and the headwaters of the San Francisco River. The ground water of the Chihuahuan Desert is limited and almost entirely characterized by the confined Edwards-Trinity aquifer under its far southeastern section in Texas and the confined aquifers associated with the Pecos and Rio Grande Rivers. The ground water of the Chihuahuan Desert is principally used for irrigation and municipal water supplies.

Climate

Summers are long and hot. Winters are short but may include brief periods when temperatures fall below freezing. The climate is distinctly arid. Average annual temperatures range from 50^o to 65^oF (10^o to 18^oC). Mean annual precipitation is around 8.65 in (221 mm).

Vegetation

A number of shrubs, mostly thorny, are typical of the Chihuahuan Desert. They frequently grow in open stands, but sometimes form low, closed thickets. In many places, they are associated with short grass, such as grama. Extensive arid grasslands cover most of the high plains. Creosote bush, honey mesquite, cacti (particularly prickly pear), and yucca are abundant. Cottonwoods and other trees may grow beside the rivers; juniper and pinyons are prominent in western Texas. Some isolated mountains carry a belt of oak and juniper woodlands, pines, and firs.

Fauna

Pronghorn antelope and mule deer are the most widely distributed large game animals with some whitetail deer in Texas. The collared peccary or javelina is common in the southern part of the region. Herbivores include blacktail jackrabbit, desert cottontail, kangaroo rat, wood rat, and numerous smaller rodents. Mammalian predators include the coyote and bobcat.

The black-throated sparrow is one of the most abundant birds. Greater roadrunner, curve-billed thrasher, Chihuahuan raven, scaled quail, and Gambel's quail occupy most of the area; bobwhite populations reach into its eastern portion. Raptors include the golden eagle, great horned owl, red-tailed hawk, ferruginous hawk, and the rare zone-tailed hawk.

The many reptiles include the common chuckwalla, Texas horned lizard, desert spiny lizard, and various species of rattlesnakes.

Common fish fauna found in the Chihuahuan Desert include the gar, American eel, common carp, suckers, catfishes, black basses, and sunfishes. Threatened or endangered fish fauna found in the Chihuahuan Desert include the Peco bluntnose minnow, Gila topminnow, and Gila trout.

References