干旱区生态环境知识资源中心

In many dryland ecosystems biological crusts are dominating the soil surface. The ecological importance of these crusts is related to their resistance against erosion caused by wind or surface runoff, and to the protection of infiltrated rain water against excessive evaporation. This study demonstrates that optical remote sensing systems provide a good potential to assess the existence of biological soil crusts and to differentiate various types of crusts, thereby providing important information on areas of stability and disturbance in arid ecosystems. DAIS hyperspectral data acquired in August 1997 permit a thorough analysis of the reflectance signal determined by mixtures of vascular desert plants and biological crusts developed on bright background substrates. It is expected that this will resolve ambiguities about understanding the nature of the sharp contrast along the Israeli-Egyptian border observed from space.