The goal of this project is to conduct basic study with relevance to management of public lands in the BLM California Desert District. This region is faced with changes to vegetation associated with climate change and drought. Dieback of woody species has occurred on the eastern side of the San Bernardino and San Jacinto Mountains where evergreen forest and chaparral shrubs grade into Desert. Loss of woody species allows opportunities for invasive species to establish. Changes in vegetation alter components of the water cycle. Drought resistance will be determined by measuring the reduction in water transport of plant stems as a function of decreasing water potential. These ¿vulnerability curves¿ represent a standard technique for comparing drought resistance among species. Water use by invasive species will be determined using measurements of stomatal conductance and transpiration for herbaceous species and sap flow for woody species.