Characterization of Chihuahuan desert vegetation phenology using high temporal resolution satellite imagery

Abstract

In the mid‐1800s, desert grasslands dominated much of the northern Chihuahuan Desert of the southwestern USA. Since that time, extensive degradation of those grasslands has occurred largely as a result of periodic drought and overgrazing. The present landscape in this region is characterized by scattered patches of the once extensive grasslands, separated by large areas of desert shrubland. Our research provides an evaluation the utility of high‐temporal resolution satellite imagery to characterize degradation processes in Chihuahuan desert vegetation. We calculated the normalized difference vegetation index at intervals throughout the growing season and combined the images into a single‐multitemporal file. Classification of the image was based on temporal dynamics of vegetation. Results were graphed for areas classified as grass and shrubland, and compared with ground data on cover, composition measures, and estimated level of degradation. Phenology of vegetation based upon satellite‐derived NDVI shows a shift from summer growth to spring growth. Through a satellite image based evaluation of these growth characteristics, we show that it is possible to detect changes in plant community composition from grasses to shrub, a process indicative of vegetative land cover degradation in this region.