[Changes in Carbon Storage and Multi-Scenario Prediction in the Beijing-Tianjin Sandstorm Source Region Using a Coupled PLUS-InVEST Model].

Quantitative assessment and prediction of the impacts of regional land use changes on ecosystem carbon storage have profound practical significance for achieving sustainable regional development. Focusing on the Beijing-Tianjin Sandstorm Source Region （BTRSSR）， a key target area of the Grain for Green Program， this study leveraged land use data extending from 2000 to 2020. We first analyzed the spatiotemporal patterns of land use changes within this period. Subsequently， the InVEST model was employed to discern the spatiotemporal distribution and dynamics of carbon storage. Furthermore， the Markov-PLUS model was applied to forecast the land use patterns and corresponding changes in carbon storage for the year 2040 under the three scenarios of natural development， urban development， and ecological conservation. The key findings are as follows： ① Land Use Dynamics （2000-2020）： The BTRSSR showed an expansion of forestland， grassland， shrubland， and construction land， accompanied by a contraction in water bodies， cultivated land， and unused land. Notably， cultivated land primarily transitioned to grassland， forestland， and construction land， while unused land primarily converted to grassland. ② Carbon Storage Trends （2000-2020）： Overall， the region's carbon storage exhibited an upward trend， with a total increase of 7.92 Tg. Spatially， a gradual decrease in carbon storage was observed from southeast to northwest. The augmentation of forestland and grassland emerged as the primary driver behind this increase in regional carbon storage. ③ Future Projections （2040）： With the exception of the urban development scenario， both the natural development and ecological conservation scenarios project further increases in future carbon storage in the BTRSSR. Notably， under the ecological conservation scenario， the projected total carbon storage reaches 4 243.65 Tg， surpassing that of the natural development scenario by 8.04 Tg. This underscores the assertion that the Grain for Green Program effectively enhances ecosystem carbon storage， with the ecological conservation scenario identified as the optimal development pathway for the study area. These findings highlight the critical role of land use management policies， particularly those promoting ecological restoration， in enhancing regional carbon sequestration and fostering sustainable development.