Assessment of eco-environmental quality changes and spatial heterogeneity in the Yellow River Delta based on the remote sensing ecological index and geo-detector model

As the youngest wetland ecosystem, the Yellow River Delta (YRD) has well-structured and species-rich natural wetland resources. However, its eco-environment is very fragile due to the existence of long-term natural and man-made pressures. Along these lines, the ecological quality assessment is considered of great significance to the sustainable development of the YRD. More specifically, spatial differentiation is regarded as the spatial manifestation of both natural and anthropogenic pressure on the eco-environment quality (EEQ). From the spatial heterogeneity analysis, the driving factors can be revealed and a reliable basis for environmental governance in this region can be provided. To the end, based on the Google Earth Engine (GEE) cloud platform, a remote sensing ecological index (RSEI) was developed here to quickly, objectively, and efficiently evaluate the EEQ in the YRD. Moreover, the spatial heterogeneity of the eco-environmental quality and the interaction among the driving factors in this region were quantitatively analysed by using the geo-detector model (GDM). The results indicated that (1) the EEQ of the YRD exhibited a slightly improved trend from 2013 to 2021; (2) the overall EEQ remained at an intermediate level, and at an intermediate level or above in 80% of the study area; (3) the interaction of multiple both factors affect the EEQ of the YRD, among which land-use/cover is considered the most significant factor affecting the spatial differentiation of the EEQ. It is imperative to consider the multiple factors in a comprehensive manner to realize the green economy of sustainable development in the YRD, while the role of humans in improving the ecological environment construction should be strengthened.