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