Spatiotemporal patterns and driving factors of gross primary productivity in the Shanxi section of the Yellow River Basin.

Shanxi section of the Yellow River Basin is the key region for ecological conservation and high-quality development in the Yellow River Basin, where the spatiotemporal variation in gross primary productivity directly affects regional carbon sequestration capacity and ecological security. Based on MODIS data of gross primary productivity from 2000 to 2024, we combined the XGBoost-SHAP model with the GeoDetector method to examine the spatiotemporal variations of gross primary productivity in the Shanxi section of the Yellow River Basin and to quantify the contribution of multiple driving factors to gross primary productivity and their spatial interaction effects. The results showed that gross primary productivity in the Shanxi section of the Yellow River Basin exhibited a fluctuating upward trend from 2000 to 2024, with an average annual growth rate of 13.21 g C·m-2·a-1 and an annual mean value of 665.35 g C·m-2·a-1. Spatially, gross primary productivity displayed a "low-high-low-high" pattern from northwest to southeast. Gross primary productivity showed an extremely significant increasing trend in 96.1% of the study area. The XGBoost-SHAP analysis indicated that tree cover was consistently the dominant factor influencing gross primary productivity changes across all selected study years. Precipitation and temperature, as key regulatory factors, exhibited significant stage-specific differences in their effects on gross primary productivity. The GeoDetector results showed that the interaction between tree cover and precipitation had the strongest explanatory power for the spatial differentiation of gross primary productivity. Residual analysis indicated that the contribution rates of natural factors and human activities to gross primary productivity changes were 62.6% and 35.9%, respectively. Under the combined effects of those two factors, gross primary productivity increased in approximately 98.9% of the study area during the study period.