Analysis of spatiotemporal changes and driving factors of ecological environment quality in the Mulan River Basin based on RSEI

In this study, Google Earth Engine (GEE) was used to calculate the Remote Sensing Ecological Index (RSEI) to evaluate the spatiotemporal evolution characteristics of ecological environment quality in Mulan River Basin from 2000 to 2020. The direct and indirect effects of climate, urbanization and biological factors on the change of ecological environment quality were analyzed by Partial Least Squares Structural Equation Model (PLS-SEM), and the spatial clustering characteristics of RSEI in the study area were analyzed. The results showed that: (1) from 2000 to 2020, RSEI showed an upward trend, with the lowest in 2000 (0.565) and the highest in 2015 (0.682); (2) The study area is dominated by areas with rising ecological environment quality, accounting for 80.50%; (3) Climate and biological factors have a positive impact on the quality of ecological environment, while urbanization has a negative impact. The driving force intensity of urbanization factors showed an upward trend from 2005 to 2015, indicating that the intensity of human activities in the study area is increasing; (4) The results of spatial autocorrelation analysis show that the H-H region is mainly distributed in the mountains in the northwest of the study area, while the L-L region is concentrated in the urban areas in the East, and the agglomeration intensity has been increasing since 2005.