Plant succession on disturbed sites in four plant associations in the Northern Mojave Desert

The US Department of Energy (DOE) is characterizing Yucca Mountain Nevada, as a potential site for long-term underground storage of high-level nuclear waste. DOE is committed to reclaim all lands disturbed by the project, and return them to a stable ecological state, with a composition and productivity similar to predisturbance conditions. A study was implemented to assess plant species which naturally invade disturbed sites in the Yucca Mountain Project Area. In 1991 and 1992 study plots were established on disturbed sites. Sites were characterized by disturbance type (i.e., road, drill pad, etc.), disturbance severity, vegetation association, time since abandonment, and topographic placement. Density of all perennial plant species was measured on disturbed and undisturbed plots. The species with the highest density in disturbed sites was Chrysothamnus teretifolia. This species was not a major contributor in undisturbed sites. In the undisturbed sites Ambrosia dumosa had the highest density of perennial plant species but was also high in density in the disturbance sites. Total species density was higher in undisturbed sites compared to disturbed sites. Plant species density analysis compared disturbed and undisturbed vegetation associations. Results will be used to design reclamation field trails and to finalize the Yucca Mountain Project Reclamation Implementation Plan.