Mapping Plains-Mesa Grasslands of New Mexico Using High Temporal Resolution Satellite Data

Abstract-This research uses time-series satellite sensor data set to map and examine vegetation community dynamics within semi-arid New Mexico grasslands. A multi-level image classification technique was used to extract and define grassland communities. Temporal vegetation response curves were then produced for grass-land communities. Discrimination between grassland communities was possible by examination of their unique vegetation response curves. This technique shows potential for monitoring vegetation change in semiarid grasslands, and for producing timely regional-scale vegetation surveys. Monitoring vegetation change in rangeland ecosystems is a primary concern of natural resource managers. In the state of New Mexico over 90 % of the land area is in native vegetation that is grazed by wild and/or domestic herbivores (Gay and others 1984). Considering the vast rangeland ecosystems (in the western United States alone estimated at 70 % ofthe land area), monitoring change over time becomes an enormous task (Hudson, 1991). Satellite remote sensing technology is well suited for regional studies and may provide an additional tool for land resource managers. The Advanced Very High Resolution Radiometer (A VHRR) onboard the National Oceanic and Atmospheric Administra-tion (NOAA) meteorological satellites provides several ad-vantages over other satellite sensors, including twice daily local coverage, high radiometric resolution (1024 brightness levels), and lower data cost. In addition, an extensive tempo-ral database is accumulating from the A VHRR sensors. The first A VHRR sensors, the Television Infrared Observation Satellites (TIROS-N) series were put into orbit and began recording data in 1978, and new sensors have come on-line since then and still more advanced sensors are being planned for future satellites. This research uses a temporal A VHRR sensor data set to map and examine vegetation community dynamics within semiarid New Mexico rangelands. This research was focused on the following questions: Can A VHRR sensor data be used to delineate the Plains-Mesa grasslands within New Mexico rangelands? Can these grasslands b