Human Impact

Road development and Off-highway vehicles have had significant effects on environmental conditions of the Mojave Desert. When motorcycles and trucks cruise over the dusty gravel and sand, soil compaction occurs, decreasing pore volume in the soil and making it harder for rainwater to infiltrate deep underground (Webb 159). Most of the time, the rainwater will end up evaporating before it can make its way down to the roots of thirsty desert plants (166). Construction of paved roads also serves to catalyze nonnative plant invasion. When native plants are cleared to make room for roads, competition is decreased; at the same time, water runoffs that gather by roadsides concentrate natural resources in that area, making it much easier for nonnative scrubs to take root (179). Animal mortality rates have also increased—many a speeding vehicle has run over unsuspecting rodents and reptiles.

Military activities have been ongoing since the 1940s; major training activities and exercises continue to take place, and the military facilities established in the Mojave have received more than 1 million soldiers as they passed through the region on military operations. Considering that over 46,800 square kilometers are designated as facility grounds, the damage to the area is widespread and intense. Even today, active military bases still operate, such as the National Training Center, the Marine Corps Air Ground Combat Center, the China Lake Naval Air Weapons Station, and the Chocolate Mountain Aerial Gunnery Range (Lovich). As tanks roll over the desert sand and military encampments cover the area, the soil’s top layer is removed , underground soil is compacted, and the diversity of native plants has decreased.

Grazing by domestic sheep and livestock has had some effects on the desert ecosystem. 60% of the biomass above the desert floor has been reduced due to heavy grazing in the past 50 to 100 years, and scrubs and soil have been trampled under hooves, causing some decrease in shrub densities (Webb and Stielstra). The disruption of the soil, along with the effects of the road constructions, are causing more severe wind erosions and a loss of plants and animals, as herbivores that feed off the damaged shrubbery lose their food sources.  Continued grazing may exceed the capacity of the desert’s sustainability. (Webb and Stielstra).

Other anthropogenic factors continue to contribute to the damage on this desert ecosystem, including mining, farming, urbanization, and man-made fires (Lovich). Further research is required to measure the exact extent of the damages caused by human activities.

 

Works Cited:

Webb, Robert H., Lynn F. Fenstermaker, Jill S. Heaton, Debra L. Hughson, Eric V. Mcdonald, and David M. Millar, eds. The Mojave Desert: Ecosystem Processes and Sustainability. Reno, Nevada: University of Nevada Press, 2009. Print.

http://www.springerlink.com/content/pyhr28ncjnt8ppuc/fulltext.pdf

http://www.springerlink.com/content/p5747r8557672125/fulltext.pdf