Desert pavement surfaces in the Mojave Desert region that were observed over a period of several decades to have been essentially free of annual plant growth were observed this spring to have been invaded by dense growths of annual vegetation. It is inferred that this unusual increase in pavement biomass was due to the abnormally wet weather associated with the recent El Nino event. This proposal requests support for an immediate field visit to affected pavement sites to document vegetation patterns and densities before the vegetation fades with increasing seasonal temperatures, and to assess any changes that may have been caused either directly or indirectly (via foraging animals) to the otherwise stable pavement surfaces. A follow up field trip is planned for this coming fall. The results of this field study will be used to determine whether surface clast patterns on otherwise stable desert pavement surfaces contain information about past variations of environmental variables such as local precipitation.
