Long-Term Dynamics of Land Degradation Risk in Arid Northwest China Revealed by an Integrated Risk Index

Abstract

Dryland degradation increasingly compromises ecosystem stability, food production, and regional development. Clarifying its long-term evolutionary patterns and regional variations is therefore essential for formulating targeted management strategies. Leveraging GEE, we assembled multiple remote-sensing products together with land-cover information to establish a 1-km-resolution assessment framework describing vegetation conditions, drought pressure, potential soil salinity, and the ecological status associated with different land-cover types. An entropy-based weighting scheme was subsequently employed to derive the land degradation risk index (LDRI). This index enabled an assessment of changes in land degradation risk across arid Northwest China over the period 2001–2024, while also allowing the relative contributions of the principal driving factors to be evaluated. The analysis indicated that degradation risk generally weakened throughout the region, and shifts among risk categories occurred predominantly through stepwise movement between neighboring levels. Areas shifting toward lower-risk classes accounted for 75.36% of the total area experiencing risk-class changes. Nevertheless, High risk areas continued to be concentrated in the central-western desert belt, while the overall spatial pattern showed limited variation. Driver analysis indicated that vegetation productivity and hydrothermal conditions had relatively high explanatory power, while interactions among factors generally exhibited enhanced effects. Further stratified analysis showed that land degradation risk in vegetation zoning was mainly controlled by moisture conditions and vegetation productivity, whereas hydrothermal conditions exerted a stronger influence in non-vegetation zoning. The proposed LDRI provides a distinct analytical framework for the long-term monitoring and spatially differentiated management of land degradation risk across arid Northwest China, with broader implications for the scientific assessment and management of dryland degradation.