SATELLITE IMAGE AND GIS-BASED IDENTIFICATION AND CHARACTERIZATION OF WET MEADOWS IN THE CENTRAL GREAT BASIN

The Great Basin is an arid landscape with limited water availability to sustain wetland vegetation and water-dependant ecosystems. Wet meadow, riparian corridor, and headwater source ecosystems are more common in high elevation mountain drainage systems where groundwater is shallow or discharges from springs. Wet meadows are dominated by grasses such as sedges and rushes, riparian corridor vegetation assemblages are dominated by willows, water birch, wild rose, and cottonwoods, and headwater source vegetation assemblages are dominated by quaking aspen, cottonwoods, and grasses. The ecological importance of these environments is magnified because they comprise a small percentage of the overall landscape. Recent work has shown that these ecosystems are susceptible to degradation by channel incision and resultant lowering of the groundwater table. As a first step towards developing a management plan for these ecosystems we have used color-enhanced 1:50,000 scale satellite images to identify and classify wet meadows, riparian corridor, and headwater source vegetation units. A GIS was used along with digital copies of geologic and topographic maps to create a database that included morphometric characteristics, site geology, proximity of springs, faults, and other features for each site. Higher resolution color and black and white aerial photos with scales as large as 1:3,000 along with field reconnaissance were used to refine the satellite image based classification of meadows and riparian vegetation corridors. The database will serve as a basis for identifying the fundamental controls on the distribution of wet meadows in the Great Basin and also as a starting point for establishing a prioritization hierarchy for management purposes.