Images © by James L. Reveal, Norton-Brown Herbarium, University of Maryland, unless otherwise credited.

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Creosote bush and bunch grasses in southern New Mexico

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XIIId. Chihuahuan Desert

• A. Location: Southeastern Arizona, southern New Mexico and western Texas southward to the trans-volcanic belt of San Luis Potosí in north-central Mexico.
  
  

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  Limestone slopes with creosote bush, Coahuila

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  B. Features:

  • 1. Low, scattered and isolated, mostly limestone, short mountain ranges.
    2. Warm to hot summer temperatures, cold and often freezing temperatures in the winter.
    3. Precipitation as cold rain or snow Dec to Mar; warm rains Jul through Sep.
    4. Warm spring and fall means growing season of 200 or more days a year.

  C. Vegetation:

  • 1. Creosote bush is dominant; tarbush (Flourensia cernua) can be a co-dominate.
    2. Thorny shrubs (mainly species of catclaw [Acacia]) are common along with species of ocotillo.
    3. Small trees and arborescent cacti are not common compared to the Sonoran Desert.
    4. Century plants (Agave) and Spanish-bayonet (Yucca, see right) common in places.
    5. Numerous and diverse kinds of cacti: Peyote (Lophophora williamsii) is now rare. Many species of barrel cacti (Ferocactus), hedgehog cacti (Echinocereus), cholla or prickly pear (Opuntia), fishhook cacti (Mammilaria, see right), and a host of lesser genera in terms of numbers of species (e.g., Strombocactus, Neolloydia, Coryphantha).
    6. Grasses common; many endemic herbaceous perennials and small shrubs on gypsum outcrops, in limestone mountains, and around desert oases such as Cuatro Ciénegas, the beautiful site of numerous endemic species, especially fish.
    7. Resurrection plant (Selaginella lepidophylla, S. pilifera), are spikemosses that curl up and brown when dry but unfold and turn green when wetted.

  D. Animals:

  • 1. Deer, antelope, feral goats and pigs.
    2. Numerous resident birds; scattered waterfowl

  E. History:

  • 1. Desert was prairie grassland into Late Pleistocene, became desert during hypsithermal period (ca. 12,000-10,000 years ago).
    2. Rapid change resulted in rapid, localized speciation.

  
  

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  Tumbleweed against a barbed wire fence, New Mexico

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  F. Exploitation:

  • 1. Extensive, long-term overgrazing has resulting in many introduced weeds, most notably the Old World tumbleweed (Salsola spp) now found throughout the West.
    2. Some mining and limited logging especially in mountains.

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End of an evening rain storm, Sierra del Pinos, Coahuila

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Desert main page Tropics
Main Terrestrial Biomes page

Last revised: 17 Oct 1997 - Reveal