Large areas of the southern California desert ecosystem have been negatively affected by off-highway-vehicle use, overgrazing by domestic livestock, agriculture, urbanization, construction of roads and utility corridors, air pollution, military training exercises and other activities. Secondary contributions to degradation include the proliferation of exotic plant species and a higher frequency of anthropogenic fire. Effects of these impacts include alteration or destruction of plant communities, destruction of soil stabilizers, soil compaction, and increased erosion. Published estimates of recovery time are based on return to pre-disturbance levels of biomass, cover, density, community structure, or soil characteristics. Natural recovery rates depend on the nature and severity of the impact but are generally very slow. Recovery to pre-disturbance plant cover and biomass may take from 50-300 years while complete ecosystem recovery may require over 3,000 years. Restoration can be used to enhance the success and rate of recovery, but the costs are high and the probability for long-term success is low to moderate. Given the sensitivity of desert habitats to disturbance and the slow rate of natural recovery, the best management option is to limit the extent and intensity of impacts as much as possible.

This project started in 1991 when the Bureau of Land Management received a grant from the California Department of Parks and Recreation, Off-Highway Motor Vehicle Recreation Division to conduct an extensive review of the literature pertaining to restoring degraded desert tortoise habitat, with emphasis on the Mojave Desert. The first product was a major report summarizing information contained in about 400 references. The report contains an indexed, sorted, and partially annotated bibliography.

This badly scarred hillside near Palm Springs, California shows the impacts of heavy use by off-highway vehicles. Research suggests that such scars will be visible for centuries.

PRODUCTS

Lovich, J. E. 1992. Restoration and revegetation of degraded habitat as a management tool in recovery of the threatened desert tortoise. Contract Report prepared for California Dept. Parks and Recreation, Off-Highway Motor Vehicle Recreation Div. U.S. Dept. Interior, Bureau of Land Management, California Desert District. 187 pp.

Lovich, J. E. 1999. Human-Induced Changes in the Mojave and Colorado Desert Ecosystems: Recovery and Restoration Potential. Status and Trends of the Nation's Biological Resources. 2 vols. In pp. 529-531, 541-542., M. J. Mac, P. A. Opler, C. E. Haecker, P. D. Doran, and L. Huckaby (eds.). Department of the Interior, Washington, D.C.

Lovich, J. E. and D. Bainbridge. 1999. Anthropogenic degradation of the southern California desert ecosystem and prospects for natural recovery and restoration. Environmental Management 24:309-326.
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