Land degradation, soil erosion and desertification monitoring in Mediterranean ecosystems

Abstract

Abstract Under the European Commissions's DG XII "Research & Development Programme in the Field of the Environment" emphasis is given to identify, map and control desertification phenomena in the Mediterranean area. Based upon previous experiences in Mediterranean land cover mapping, the "Environmental Mapping and Modelling Unit" of the Institute for Remote Sensing Applications is actively participating in this programme. A semi‐operational approach to land degradation mapping has recently been developed which requires radiometric rectification of the multi‐spectral images and the availability of spectral libraries. Linear spectral mixture modelling is then used to decompose image spectra into their spectrally distinct components, the fractional abundance of which then provides a largely unbiased measure for direct mapping of vegetation abundance and the identification of soil conditions and erosion hazards. Ground verification in a well‐controlled test site in the south of France proved an excellent accuracy in identifying soil degradation levels with both airborne imaging spectrometry (AVIRIS) and Landsat TM data. The same method with identical processing parameters was then applied to Thematic Mapper images from a different Mediterranean region (Peloponnesos, Greece). Results confirmed the experiences of the first study site, thereby suggesting that the approach holds the potential for operational applications, including monitoring of erosion processes and changes in vegetation cover (desertification monitoring).