A new index for mapping lichen-dominated biological soil crusts in desert areas

Abstract

Tracking the presence, distribution and disappearance of biological soil crusts is important for ecosystem management of desert regions and provides highly valuable information on desertification and climate change studies in arid environments. Based on the analysis of the spectral features of biological soil crusts, we propose a new biological soil crust index (BSCI) for biological soil crusts mapping. Using both a radiative transfer simulation and an analysis of a Landsat Enhanced Thematic Mapper Plus (ETM+) image, we examined the ability of satellite remote sensing to detect and map biological soil crusts. Our simulation indicated that Landsat ETM+ data could be used, after atmospheric correction, to detect biological soil crusts if 33% or more of any pixel was accounted for by biological soil crusts. When the proposed BSCI was applied to the detection of biological soil crusts in the Gurbantonggut Desert, Xingjiang, China, a Kappa coefficient of 0.82 and an overall accuracy of 94.7% were achieved. These experimental results indicate that the new index is applicable to identification of lichen-dominated biological soil crusts, and therefore has good potential for biological soil crust detection and mapping in cool and cold deserts.