A Knowledge-Based Approach for Mapping Land Degradation in the Arid Rangelands of North Africa

Abstract

Rangelands cover about 82% of the arid area of Morocco. It is generally acknowledged that these areas are threatened by desertification. Monitoring desertification requires accurate knowledge about the current status of rangeland degradation. Remote sensing is widely used to assess changes in land cover, but its use in arid rangelands has limitations because of spectral confusion among various types of land cover. The objective of this study was to assess the severity and spatial extent of rangeland degradation in the high plateaus of eastern Morocco, using a knowledge-based approach combining remote sensing and ancillary data. This approach relies on analyzing datasets derived from Landsat TM satellite imagery, lithology, bioclimatic data and field measurements. The level of rangeland degradation was assessed using indicators such as vegetation parameters, grazing levels and cultivation intensity, which provided a high level of accuracy for mapping and monitoring the degradation of the arid rangelands. The results showed that the total area of degraded rangeland in the high plateaus of eastern Morocco is about 17,417 km2, accounting for 48% in the studied area.