PARENT SESSION
Oral Session # 70: Landscape Ecology.
Presiding: S Hannon
Thursday, August 7. 8:00 AM to 11:30 AM, SITCC Meeting Room 201.
Repeated geological perturbations and long-lived creosotebush in the Mojave Desert.
McAuliffe, Joseph*,1, Hamerlynck, Erik2, Eppes, Martha3, 1 Desert Botanical Garden, Phoenix, AZ2 Rutgers University, Newark, NJ3 University of North Carolina, Charlotte, NC
ABSTRACT- Individual genetic clones of creosotebush (Larrea tridentata) have persisted for thousands of years at a site in the Mojave Desert, California. Paradoxically, these clones are rare or absent on the older, more stable geomorphic surfaces in the area, but instead are found where fluvial and eolian processes have repeatedly disturbed the soil surface throughout the Holocene. These disturbances prevent the formation of a fine-textured soil horizon (vesicular A or Av horizon) directly beneath the surface. When present, this horizon strongly inhibits infiltration of precipitation and negatively impacts plant water status. The geologically dynamic nature of the Mojave Desert environment, rather than geological stability per se, has allowed the persistence of clones through lengthy episodes of extreme climatic drought during the last several thousand years.
Key words: creosotebush, Larrea tridentata, mojave desert, biogeomorphology