Old field succession in Mojave desert scrub

Secondary (old field) succession in Mojave Desert scrub vegetation was studied in 20 abandoned homestead fields in the uplands of the eastern Mojave Desert, California. The fields, which were last plowed between 1913 and 1930, were stratified equally in three vegetation types: creosote bush scrub (1 100 m elevation), Joshua tree grassland (1280 and 1430 m), and sagebrush/juniper scrub (1615 m). Cattle grazing has been the only widespread disturbance since the fields were abandoned. Our investigation of cover and size of perennial plants indicated that secondary succession in creosote bush scrub is approaching climax (off-field conditions) within approximately 65 years, but that succession in vegetation at higher elevations may require