Tracking desertification fronts in Arid landscapes using multi-temporal landsat data and a composite spectral index

Desertification poses a major threat to arid ecosystems, particularly in oasis environments where ecological balance and agricultural productivity are closely linked. This study investigates spatiotemporal dynamics of desertification in the Tata Oasis (southeastern Morocco) using the Desertification Monitoring Index derived from Landsat-8 imagery (2013–2024). The DMI integrates MSAVI, albedo, and SFI to provide a comprehensive assessment of land degradation. To enhance temporal analysis, a structured multi-period framework (P1: 2013–2015; P2: 2016–2018; P3: 2019–2021; P4: 2022–2024) was applied to characterize degradation trajectories and spatial patterns. Results indicate a shift from stability in P1 to accelerated degradation in P4, with expanding degradation fronts in peripheral and abandoned lands and increasing fragmentation of productive areas, while the oasis core remains comparatively stable. Validation with 285 GPS points yielded 92% overall accuracy and a Kappa coefficient of 0.901. The findings support targeted land management under climatic and anthropogenic pressures.