Plant Survey of Current Vegetation: MAP OF SONORAN DESERT PLANT COMMUNITY DISTRIBUTION IN THE CAPLTER STUDY AREA, PHOENIX, ARIZONA

This study represents an effort to map the distribution of plant community types across the Central Arizona - Phoenix Long Term Ecological Research (CAP-LTER) site centered in metropolitan Phoenix using Landsat ETM data. Vegetation classification was carried out using field data collected from within the study area describing woody plant species. A system was devised which represented a compromise between providing floristic information and enabling maximum spectral discrimination between community types. Image classification used reference spectra derived from training sites in the field and was carried out on subsets defined by soil surface texture in order to control for the strong background soil signature inherent to arid regions. While groundtruthing revealed that vegetation on clayey soils was mapped to 91% accuracy, other sections produced maps with less accuracy. The results of this study demonstrate that image classification of desert vegetation using only Landsat ETM data is problematic and may not be practical without other supporting data, such as radar imaging.This project attempts to produce a vegetation distribution map across undeveloped parcels of outlying desert wilderness, as well as remnant mountain parks throughout the city, contained within the Central Arizona Phoenix Long Term Ecological Research (CAPLTER) study area. This effort seeks to create the first successful classification map of Sonoran Desert vegetation derived from satellite imagery. The map would also be the first fine-scale map of plant community types in the Phoenix region. The depiction would allow for a calculation of the land area covered by each vegetation class, and which communities are exposed to development pressures. This map potentially provides a basis from which researchers can measure vegetative biomass distribution across the landscape and attempt to incorporate this component into ecological models of energy flows and biogeochemical cycling in the CAP-LTER site. Information on vegetation location can also assist with sampling stratification in other research projects. Finally, this map would provide a valuable basis from which future changes in vegetation distribution can be assessed