The Mojave Desert

The Mojave Desert and its Anthropogenic Impacts

by Rachel Venturino

 (http://rango.wikia.com/wiki/Mojave_Desert)

 History      

      

        The Mojave Desert takes up a large portion of southeastern California, sections of central California, southern Nevada, southwestern Utah, and northwestern Arizona.  This desert receives around 12 inches of rainfall annually, and its elevation is between 2,000 and 5,000 feet.  11,000 years ago, the ecological zones of the Mojave Desert were one thousand feet lower in elevation than today due to the cooler and wetter weather patterns of the waning Ice Age.  In addition, streams flowed and lakes existed where dry lakes currently exist.  The relative abundance of plant communities supported wildlife and indigenous peoples depended upon the natural resources of the Mojave.  Historically, the Cahuilla Indians inhabited this desert region, and like other Native American peoples, they relied on their environment to survive.  Of the resources available to them, one included the mesquite tree, which served many purposes.  The Natives used mesquite wood, bark, and leaves to build their homes, as well as a staple food item, making tea out of the seeds and eating the dried and ground mesquite seedpods.  Up to this point in history, the human population was sparse and its environmental impact was sustainable.  The problem that has arisen in recent years is the growing urbanization that has occurred in various regions throughout the Mojave, which has caused many negative effects on this desert’s complex ecosystem.  The anthropogenic impacts of urbanization include but are not limited to the development of railways and cities, groundwater pumping, and the construction of roads.

 

 (http://www.blueplanetbiomes.org/mojave_desert.htm)

  

Anthropogenic Impacts

             

        Even though historically humans have not heavily populated the Mojave Desert, it has increasingly become urbanized in recent years.  Las Vegas Nevada is the largest city in the Mojave, with a metropolitan population of around 1.9 million in 2006.  In addition, over 850,000 people live in areas of the Mojave attached to the Greater Los Angeles metropolitan area including Palmdale and Lancaster.  One of the main problems associated with urbanization is that it leads to the destruction of natural habitat, which leads to the forced relocation or elimination of plant and animal species that inhabit the area.  In addition, urbanization results in the depletion of local resources such as water and vegetation that many animal species rely on for survival.  In this way, urbanization has led to many plant and animal species in the Mojave Desert becoming endangered or threatened such as desert tortoises, bald eagles, mountain lions, bad water snails, the bear-paw poppy, and the panamint daisy.  In addition, land managers have to deal with competing uses for the land including all-terrain vehicles, motorcycles, military use, mining, and livestock and agriculture, all activities undoubtedly contributing to the amount of endangered and threatened species.

  (http://landcovertrends.usgs.gov/west/eco14Report.html)

           

       The Mojave Desert contains four national parks in which humans take part in many recreational activities.  The problem with this is that even a single footprint has a long-lasting effect on desert ecosystems: nitrogen fixation stops in the soil and underlying soil connections are broken.  In this case, most human activities in the Mojave Desert are harmful to biological soil crusts, which are the layers of soil whose particles cohere because of organic material including live organisms and their waste products.  These crusts cannot handle the compressional stress caused by the footprints of livestock and people or by the tires of vehicles.  Because most living crust biomass is concentrated in the top 1/8th inch of the soil, even small impacts can have profound consequences.  Crushed crusts contribute less nitrogen and organic material to the ecosystem and the soils are left highly susceptible to both wind and water erosion.

            Future Prospects

        Although the human encroachment into the Mojave Desert in the forms of recreation and urbanization has had many negative impacts, some areas impacted and abandoned by humans such as old railroad tracks do have a chance for recovery.  Leonard Gaydos, Coordinator for the U.S. Geological Survey's (USGS) Recoverability and Vulnerability of Desert Ecosystems project has been using satellite data to develop tools that will help Mojave Desert land managers decide what recreational activities to allow and where to allow them.  Gaydos has stated, "The good news is that the desert seems to recover faster than earlier models predicted.  The bad news is that it still takes the land a long time to return to its original state, and, in some cases, it may never be exactly what it was before the disturbance occurred".  This is due to the fact that the damage that has been done to the organic material underneath the soil’s crust cannot be easily repaired since the living organisms in the soil only inhabit the soil’s surface.  Under good conditions, a thin veneer of cyanobacteria may return within five years.  Unfortunately though recovery may take up to twenty years in locations of the Mojave Desert that receive a measurable amount of rainfall, and could take over 250 years in places that receive extremely low rainfall.  Both of these estimates are assuming that an area is not impacted by any more disturbances.

            

Protection and Restoration

        Restoration is a key practice that humans should continue in the Mojave Desert, preferably on a larger scale than currently taking place.  The success of such restoration is evident through a recent project in the Mojave Desert, in which seedlings planted in the summer with temperatures above 100°F and located far from water systems had a survival rate above 80%.  National parks are mostly successful in protecting the environment from development, yet they cannot fully protect the ecosystems of the Mojave.  This is due to the fact that ecological damage still occurs from recreational activities, walking, and driving.  These areas protected from human development are extremely important to maintain and expand.  This is because the environmental impact caused by foot and car traffic within protected areas is far less than the impact of urbanization.  There are also other ways individuals and organizations interested can get involved in preserving the Mojave.  An example of a successful protection effort is the Mojave Desert Land Trust, which has protected almost 28,000 acres of desert land, through acquisition, conservation easements and strategic partnerships.  Education is another important component of ecosystem protection necessary to improve and continue positive human impacts on the environment.  Many programs have developed in national forests and in schools in and around the Mojave Desert that teach individuals how to respect the environment and its natural resources when visiting the Mojave ecosystem.  

 (http://www.appl.org/i4a/pages/index.cfm?pageid=3334)

Population trends in counties of the Mojave Basin and Range Ecoregion:

 (http://landcovertrends.usgs.gov/west/eco14Report.html)

Works Cited

"Children and Public Lands - Association of Partners for Public Lands." Home - Association 

         of Partners for Public Lands. Web. 30 Nov. 2011. <http://www.appl.org/i4a/pages

         /index.cfm?pageid=3334>.     

 Luckenbach R (1982) Ecology and Management of the Desert Tortoise (Gopherus  

        agassizii) in California. In: Bury RB (ed) North American tortoises: conservation

          and ecology. Wildl Res Rep12, USDI Fish and Wildlife Service, Washington, DC.

   

"The Mojave Desert - DesertUSA." Desert Biomes by DesertUSA. Digital West Media, Inc.      

        Web. 28 Nov. 2011. <http://www.desertusa.com/du_mojave.html>.

"Mojave Desert." Blue Planet Biomes. Web. 30 Nov. 2011.  

         <http://www.blueplanetbiomes.org/mojave_desert.htm>.

"Mojave Desert." Rango Wiki. Web. 30 Nov. 2011. <http://rango.wikia.com

         /wiki/Mojave_Desert>. 

  Sleeter, Benjamin M. “Mojave Basin and Range Ecoregion Summary” USGC Land

         Cover Trends Project. 12 April 2011. 

         http://landcovertrends.usgs.gov/west/eco14Report.html

Schmidt, Laurie. "Human Impact on the Mojave (DAAC Study) : Feature Articles." 

          NASA Earth Observatory : Home. Web. 28 Nov. 2011.

             <http://earthobservatory.nasa.gov/Features/Mojave/>.

Weeks, John Howard. (1998) Mojave Desert.  New York: Arcadia Publishing