An integrated approach based on ecological and geo-environmental indicators for the spatio-temporal monitoring of desertification: The case of the Skoura oasis (Morocco)

The Skoura oasis, located in the Ouarzazate region of southern Morocco, represents a fragile agro-ecosystem increasingly affected by land degradation processes. This study aims to analyze the spatio-temporal dynamics of desertification in the oasis from 1984 to 2024, in light of climate variability and anthropogenic pressures. An integrated approach combining remote sensing data and environmental indicators is adopted to characterize changes in vegetation and soil conditions. High-resolution satellite imagery from Pléiades 2023 and time series data from the Landsat (5, 7, 8) and Sentinel-2 missions are processed using object-based image analysis and segmentation techniques. Three key indicators are employed: the Modified Soil Adjusted Vegetation Index (MSAVI), surface albedo, and the Sand Fraction Index (SFI). These indicators are integrated to construct a Desertification Monitoring Index (DMI) within the Google Earth Engine platform. Results reveal that in 1984, 24.3% of the oasis area was already classified as highly desertified, particularly in the eastern, southern, and central zones. A slight improvement was ob-served by 1996, with the desertified surface decreasing to 8.6 %. However, a renewed intensification occurred between 1996 and 2010, especially in areas dominated by date palms and olive groves. From 2010 to 2024, desertification progressed further, marked by significant vegetation loss. The findings highlight the persistence and aggravation of land degradation over four decades. The study demonstrates the value of integrated remote sensing approaches for monitoring desertification and supports the need for adaptive strategies to ensure the sustainable management of oasis ecosystems.