干旱区生态环境知识资源中心

ComparipIsand degradation in arid, semi-arid, and dry sub-humid areas result from various factors, including climate variations and human activity, and can lead to desertification. The process of degradation results in simultaneous and complex variations of many interrelated and coupled soil-vegetation parameters. General information and data regarding the degree and extent of land degradation and the resulting impacts remain poorly understood and remote sensing can play a major role by providing a quantifiable and replicable technique for monitoring and assessing the extent and severity of soil degradation. In this study we investigated various 'optical' indicators and early warning signals of land degradation and desertification with the use of hyperspectral remote sensing data derived from EO-1 Hyperion and AVIRIS sensors. Utilizing spectral mixture analysis, we analyzed simultaneous spatial variations in vegetation cover, species, physiognomy, albedo, and soil properties at various sites representing different stages of land degradation in the Mendoza regions of Argentina and at sites in the Southwest U.S.A. We found that both soil and vegetation parameters were required to characterize the unstable and spatially variable landscape dynamics found in actively degrading environments.