Desert Life

Introduction

Although it may not be apparent to the casual observer, animal and plant life abounds in the southwestern deserts of the U.S. Life is profuse here because both desert animals and plants have acquired special adaptations to solve the dual problems of desert survival -- excessive heat and very limited supplies of water.

Throughout the deserts of the Southwest, availability of water is the most critical factor in sustaining plant life. Local environmental conditions (soil, elevation, latitude, direction, to name a few) are also significant in determining the makeup and character of individual desert plant communities and the various animal species which depend on them for things like food, water, shelter and shade.

The ability to survive the harsh desert environment is often enhanced by mechanisms that involve symbiosis, in which members of both the plant and animal kingdoms live together in a mutually beneficial relationship, each depending on the other for survival.

Considering the many ingenious ways animals and plants have learned to cope with this arid environment, and the numerous types of terrain available, it is really not so surprising that such a large and varied population of life forms inhabits the deserts. But there is one more life form to consider -- humankind.

Humans often play a major role in altering the environment, and nowhere is this more critical than in the fragile, arid regions of the earth. Through human intervention, semiarid lands can easily be turned into desert, and already arid lands can be quickly rendered biologically unproductive.

Desert trees and shrubs are often trampled, cut for fuel or overgrazed by domestic animals. Livestock (especially cattle, sheep and goats) can easily destroy grasslands in semiarid regions. Marginal lands are often cleared for agriculture exposing soil to wind and water erosion. And through improper irrigation, saline surface and ground water can sterilize the desert soil with salt and alkali.

When humans no longer maintain a symbiotic relationship with arid lands, when they begin to drastically alter the environment making it less life-sustainable for plants and animals, it is called desertification. The major earmarks of desertification are:

• Declining groundwater tables
• Salinization of topsoil and water
• Reduction of surface waters (streams and lakes)
• Unnaturally high soil erosion
• Desolation of native vegetation
• Loss of natural biological diversity (number of species)

The result of desertification is reduction of biological productivity and impoverishment of ecosystems. While the process of desertification is conspicuous in certain third-world countries, it is not limited to these regions. Ten percent of the U.S. land mass is in a state of severe, to very severe, desertification. Another 20 percent is threatened.

Read more about plant and animal adaptations to the desert environment: