Modeling Land Use Dynamics under Climate and Hydrological Changes: An Integrated Hydro-Land Framework

Climate change and hydrological variability profoundly impact land-use dynamics. Traditional one-way models often fail to capture the nonlinear evolution of these coupled systems by neglecting critical soil-water feedbacks. To address this limitation, we propose the cascaded land-hydrology coupled modeling framework (LaHyFr) to resolve bidirectional soil-water interactions under changing climates. This framework integrates a hydrological module (SWAT) that dynamically adjusts parameters using monthly land-cover updates and vegetation phenology, with a land-use module (CLUE-S) that constructs conversion probability matrices based on soil-moisture thresholds and climate stress indices. A spatiotemporal downscaling algorithm ensures scale harmonization, while the dynamic exchange between hydrological variables and land-use change dynamics ultimately establishes a closed-loop mechanism of "hydrological stress-land response-process feedback." Empirical application in the Hanjiang River Basin shows that LaHyFr improves the coefficient of determination for hydrological simulations by 13.33% and 18.05% during calibration and validation, respectively, while reducing water-balance error by 1.4% and 2.6%. For land-cover simulations, AUC and Kappa increase by 11.31% and 12.32%, confirming the model's strengths in mechanistic representation and spatial extrapolation. Scenario experiments under the SSP-RCP framework demonstrate that the model captures nonlinear soil-water responses across climate regimes. This coupled simulation system provides a transferable tool for analyzing coupled climate-hydrology-land dynamics and supports watershed management and climate adaptation planning.