Spatial and temporal variation of ecological quality in northeastern China and analysis of influencing factors

Ecological quality and its potential influencing factors are important contents of ecological security in Northeast China. Maintaining ecological security in Northeast China is of great significance for the country's ecological construction and sustainable development strategies. In this study, the Remote Sensing Ecological Index (RSEI) was used to analyze the spatiotemporal variations of ecological quality in Northeast China from 2000 to 2022 and to identify potential related influencing factors. The results show that ecological quality fluctuated during 2000–2022, showing a weak overall downward trend, especially in areas with excellent and good ecological quality where large-scale reductions have recently occurred, and the area of RSEI decline accounts for a relatively large proportion through trend analysis. RSEI exhibits strong spatial autocorrelation, with high values concentrated in the vegetation-covered regions of the north and central regions, and low values clustered in urban areas and human activity areas in the west. Elevation, precipitation accumulation, wind speed, vapor pressure, and net primary productivity (NPP) are potential natural factors affecting ecological quality in Northeast China. The contribution and specific response relationships of different latent factors were analyzed using Deep Neural Network (DNN) and Multiscale Geographically Weighted Regression (MGWR) models. Based on the MGWR results, it was observed that the local coefficients not only vary over time and space, but also exhibit spatial distribution characteristics, including spatial gradient distribution and spatial clustering. As a large-scale and long-term spatiotemporal analysis of ecological quality, this study can provide theoretical support for medium-scale development planning, ecological environment monitoring, and environmental protection policy-making by decision-makers.