Coupling ecosystem services and land-use disturbance to diagnose degradation and restoration in dryland watersheds

Ecological degradation and restoration in arid and semi-arid watersheds are jointly shaped by water limitation, ecosystem-function change, and intensive land-use disturbance. However, existing assessments often treat functional status, process pressure, subsequent response, and spatial diagnosis separately. To address this gap, we developed an integrated degradation-restoration framework (IDRF) for the northern Inner Mongolia section of the Yellow River Basin using long-term land-use data and four InVEST-derived ecosystem services. IDRF links ecohydrological functional status (F), land-use process disturbance (D), disturbance-function response positions, and annual degradation-restoration screening. Because high modeled water yield does not necessarily correspond to high ecological functioning under water-limited conditions, ecologically constrained water yield (WY*) was introduced as a dryland-oriented functional adjustment. The results showed that: (1) F stably integrated multiple ecosystem services and captured watershed-scale functional gradients, providing a consistent basis for F-D response analysis. (2) D extended disturbance assessment from static land-cover attributes to process-based pressure by integrating baseline disturbance, neighborhood exposure, edge fragmentation, land-use transitions, and water/wetland support; neighborhood context was an important structural component. (3) The functional-improvement diagnostic position (τr) was lower than the composite degradation diagnostic position (τd), and this relative ordering remained stable under paired spatiotemporal resampling, indicating that improvement-related responses generally occurred at lower disturbance levels than degradation-related responses. (4) Background maintenance, stable conservation, and restoration limitation were the dominant annual screening classes, with long-term changes characterized mainly by localized transitions. During the study period, stable conservation increased from 18.20% to 21.51%, while restoration limitation remained at approximately 18%-19%. Spatial-block evaluation further supported the within-watershed discrimination of model-defined events. Overall, IDRF provides an annually updatable, watershed-scale diagnostic framework for arid and semi-arid regions where water limitation and land-use pressure interact strongly, offering a methodological basis for spatially differentiated management and targeted field verification.