Diachronic Analysis of Vegetation Cover and Soil Degradation in the Central Aurès (Algeria) Using Multi-Spectral Remote Sensing Indices

This study examines the spatiotemporal monitoring of the vegetation cover and the processes related to soil degradation in the central Aurès region of Algeria over a 33-year period (1990–2023). Using remote sensing, GIS, and multiple spectral indices (NDVI, NDWI, BI, and SI), the analysis reveals distinct phases of vegetation regeneration and regression closely linked to anthropogenic pressures and climate change. A consistently strong positive correlation between NDVI and NDWI (R ranging from 0.76 to 0.88 across all years, peaking in 2013) highlights the significant role of soil moisture on the state of vegetation. The marked negative correlations between NDVI–BI (R = –0.91) and NDVI–SI (R = –0.82) show a progressive and persistent degradation of the vegetation cover, accompanied by increasing exposure of bare soils and salinization. The shift of the BI–SI correlation from negative to positive during the study period (–0.32 in 1990 to 0.60 in 2023) indicates an ecosystemic shift toward advanced desertification. These results advocate for the urgent adoption of integrated sustainable management strategies in the Aurès Mountains.