[Spatiotemporal Changes and Driving Factors of Ecological Quality in the Jinsha River Basin Based on RSEI]

The Jinsha River Basin， upstream of the Yangtze River， one of the critical regions for ecological protection in China， plays an important role for ecosystem stability and economic development in downstream areas， as well as in the whole Yangtze River Basin. Due to the ecosystem vulnerability， it is highly susceptible to natural factors and human activities. In order to better understand the spatiotemporal changes and trends of ecological quality and its driving factors， Theil-Sen trend analysis and the Hurst index were employed to assess the remote sensing ecological index （RSEI） from 2000 to 2023. Additionally， the XGBoost model combined with the SHAP algorithm was used to analyze the driving forces for the spatial heterogeneity of RSEI. The results showed that： ① The ecological quality of the Jinsha River Basin decreased gradually from south to north， the southern region exhibited relatively high ecological quality， and the northern and central regions had lower quality. In particular， the areas with high-altitude had significantly lower RSEI due to harsh climate and sparse vegetation. ② From 2000 to 2023， the areas with significant improvements in ecological quality accounted for 31.52%， primarily located in the northern part of Yushu Tibetan Autonomous Prefecture in Qinghai， Liangshan Prefecture in Sichuan， and Lijiang City in Yunnan. Conversely， the areas with significant degradation accounted for 3.36%， mainly concentrated in the central part of Ganzi Prefecture in Sichuan. In the future， 54.79% of the total area faces the risk of ecological degradation. ③ The spatial heterogeneity of ecological quality was mainly determined by natural factors， altitude and precipitation played the most influential role compared to other factors. The above conclusions would provide a scientific foundation for regional ecological protection and sustainable development.