Delineation of erosion classes in semi-arid southern African grasslands using vegetation indices from optical remote sensing data

As stated by many authors in the recent past, soil erosion is one of the major environmental problems in southern Africa and it will become even more severe in the future due to population growth and potential climatic changes. This study concerns the detection of different land degradation stages in semi-arid grassland areas in the upper Mbuluzi-river catchment (Kingdom of Swaziland). It has been carried out within the framework of an interdisciplinary EU-funded project aimed at developing an integrated water resources management system (IWRMS) for water resources analyses and prognostic scenario planning in semi-arid catchments of Southern Africa (Flügel et al., 2001 URL: http://www.iwrms.uni-jena.de/download/Eu-reports/reportnal.pdf). Within this more general framework, particular attention was focused on the determination of high-resolution morphometric parameters for detailed erosion process studies, as well as on the derivation of relationships between vegetation cover and bare soil. The latter has subsequently been used to delineate the vegetation cover density and C-factor values for erosion models such as the revised universal soil loss equation. The examples from Southern Africa show that the methods applied are able to identify areas affected by different types of erosion. Furthermore, it is possible to estimate the parameters for a subsequent erosion modelling. Copyright © 2003 John Wiley & Sons, Ltd.