Assessment of Desertification Sensitivity Using Remote Sensing and GIS-Based MCDA Approaches in Southern Hodna, Algeria

Desertification is one of the major environmental problems in the Algerian steppe. Reasonable assessment of the sensitivity of this region to desertification using geospatial technologies like Remote Sensing (RS) and Geographical Information System (GIS) is crucial for the sustainable management of the region. In this study, the degree of desertification sensitivity of southern Hodna, was assessed, using combined remote sensing and GIS-based Multicriteria Decision Analysis (MCDA). Landsat OLI-8 image of 2016 was used to prepare six thematic maps; Land Cover (LC), salinity (NDSI), erosion (EMI), agriculture (NDVI), relative drought (NMDI), and terrestrial albedo (Albedo), which are related to the desertification process. Pairwise comparison of the thematic layers was used to measure the importance of each layer, and the weights for each one were determined based on the expert’s judgment. All thematic layers were combined using the weighted overlay tool in ArcGIS 10.3, and the desertification sensitivity map was obtained and classified into five classes, namely very high vulnerability to desertification, high, moderate, low, and very low. In addition, fieldwork was performed out in combination with a visual observation of Google Earth images to measure the accuracy of the sensitive map. Results indicated that 41.3% of the study area falls under very high and high desertification grade, whereas 29.97% falls under the non-desertification grade (very low and low), which demonstrate that this region is very affected by desertification. The validation of the results revealed that the technique used was relevant for assessing desertification sensitivity with reasonably high accuracy (87%). Finally, this finding can be used as a decision support tool for effective management and desertification control in this region.