[Spatiotemporal Evolution and Influencing Factors of Ecosystem Service Value in the Yellow River Basin].

The external spatiotemporal evolution and intrinsic impact mechanisms of ecosystem service value are of great significance for understanding regional ecosystem issues and enhancing human ecological well-being. Based on grid data, this study used the equivalent factor method and NDVI to measure the ecosystem service value of the Yellow River Basin, analyzed the spatial-temporal evolution of urban ecosystem service value along the basin, and established a GWR model to explore the spatial heterogeneity of each influencing factor on the basis of determining the main influencing factors via geographic detector. The results showed that:① The ecosystem service value of the Yellow River Basin increased first, then decreased, and finally increased from 2000 to 2020, showing a spatial distribution pattern of "the south was higher than the north;" "the lower reaches were lower, and the upper and middle reaches were higher;" and the regulation service contributed the most to the ecosystem service value of the basin. ② The results of geographical exploration showed that the degree of influence of various factors was different. Social factors played the strongest role in explaining the ecosystem service value of the Yellow River Basin, followed by economic factors, and natural factors played the weakest role. The high value areas in the upper reaches were mainly related to rivers and lakes, and the high value areas in the middle reaches were mainly related to mountains. ③ The results of the GWR model showed that population density and land reclamation rate were negatively correlated with ecosystem service value, whereas average annual precipitation was positively correlated, and the effects increased from east to west. The GDP per unit area was negatively correlated with the overall ecosystem service value but positively correlated in the upstream region.