The Chihuahuan Desert region is one of the most biologically diverse arid regions in the world. Two factors play a role in this diversity: the large size of the desert (over 200,000 square miles) and the elevational range from about 1000 ft to over 10,000 ft. The elevational ranges in particular provide different habitats that are exploited by a variety of plants and animals.

Floral Characteristics

Chihuahuan Desert Scrub—a vegetation type characterized by shrubs, stem succulents, cacti, and grass—is found in the lower elevations of the desert where annual precipitation is less than 12 inches. Cresosotebush (Larrea tridentata) is a dominant element of the Desert Scrub and can cover vast expanses. Stem succulents such as lechuguilla, sotol, and various types of yuccas are also prominent in the desert scrub. Other common shrubs include mimosa, acacia, mesquite, mariola, fourwing saltbush, tarbush, javelinabush, skeletonleaf goldeneye, allthorn, and ocotillo.

At mid-elevation, rolling grasslands dominate the landscape. These grasslands are best developed on plateaus, rolling hills, and basin floors where soils are relatively deep. Blue grama (Bouteloua gracilis) is the dominant grass species found here. Netleaf hackberry, little walnut, and a number of oaks are common woody components. Extensive tobosa grass flats occur in low elevations where water run-off tends to accumulate while beargrass and sotol commonly occur on hillsides.

Oak-Juniper-Pinyon Pine Woodlands characterize the slopes and valleys at mid-elevations. Common woodland trees include oaks, junipers, pines, Texas madrone, and bigtooth maple. Woodland shrubs include Texas mountain laurel, scarlet bouvardia, and mountain sage.

Coniferous forests can be found at the highest elevations. Typical tree species found here include ponderosa pine, douglas fir, alligator and weeping juniper, Arizona cypress and a number of oaks. Other characteristic plants include birchleaf buckthorn and needlegrass.

Riparian vegetation occurs along the major rivers and drainages in the Chihuahuan Desert region. Common riparian trees and shrubs include desert willow, cottonwoods and the introduced (and invasive) salt cedar and giant reed.

The Chihuahuan Desert region supports more cacti than any other region in the world. Many botanists believe that these plants originated here or to the south and radiated out through the New World. Common cacti include the prickly pears, hedgehogs, living rocks, nipple cacti, and cory cacti.

Within each vegetation zone are specific plant associations that are often differentiated by associated soil conditions. Examples include the characteristic vegetation of stabilized gypsum, gypsum sand, quartz sand, and saline habitats.