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

Sonoran coastal desert overlooking the Pacific, Baja California

---

XIII. Deserts

• A. Introduction:
  • 1. Desert: characterized as regions of seemingly low, sparse vegetation with minimal precipitation and humidity, high temperatures during some of the year, and great daily fluctuations in temperatures.
    2. Usually of temperate or subtropical regions.
    3. Desert formation a function of climate and topography.
    4. Deserts slow to recover from habitat damage; it is still possible to find wagon tracks from the 1840s in northern Nevada. Indian encampments are often easy to spot because the vegetation has still not recovered.
    5. Numerous unusual plants and animals make the desert home.
    

Desert floor and foothill bajadas, Stillwater Range, Nevada

Playa bottom of pluvial lake, Dixie Valley, Nevada

---

• • 6. Three major types: cold, warm or hot depending upon overall annual temperature.
    • a. Cold Deserts: Arid regions where precipitation falls sparingly principally as snow and permafrost is not a factor; vegetation is primarily xerophytic and sclerophyllous shrubs with scattered, low trees.
      b. Warm Deserts: Arid regions where precipitation falls seasonally principally as rain, some snow and frost each year; vegetation is xerophytic and sclerophyllous shrubs with scattered trees or arborescent cacti.
      c. Hot Deserts: Arid regions with little or no annual precipitation, usually rain, no snow or frost; vegetation sparse and scattered, often limited to moist areas, or even lacking entirely except following periods of adequate regional moisture.

    7. Summary:

    • a. Introduction.
      b. Origin.
      c. Environment.
      d. Biota.
      e. Population structure.
      f. Biological productivity.

  B. Four deserts in North America: Intermountain West, Mojave, Sonoran and Chihuahuan.

Light snow on the San Rafael Swells, Utah

Main Terrestrial Biome Page

Cold Deserts: Intermountain West

Warm Deserts: Mojave Desert

Warm Deserts: Sonoran Desert

Warm Deserts: Chihuahuan Desert

Last revised: 17 Oct 1997 - Reveal