[Spatial-temporal Evolution and Zoning Management of Ecological Environment Quality in Northeast China Based on MRSEI...

Northeast China is a vital ecological barrier in China, possessing abundant forest resources, mineral resources, and the largest grain production area in the country. However, the region has long been affected by human activities, resulting in a relatively fragile ecological environment. Clarifying the spatial-temporal evolution of the ecological environment quality and implementing zoning management are of great significance for promoting ecological governance and sustainable development in Northeast China. Utilizing the Google Earth Engine (GEE) cloud platform and combining the ecological characteristics of Northeast China, the modified remote sensing ecological index (MRSEI) based on five indicators of comprehensive greenness (mNDVI), humidity (WET), dryness (NDBSI), heat (LST), and air pollution (DI) was constructed. The MRSEI was employed to analyze the spatial-temporal evolution characteristics of the ecological environment quality in Northeast China from 2000 to 2024 from a multi-scale perspective (pixel, urban type, and resource type scales). The Sen+Mann-Kendall trend analysis method and Hurst index were used to investigate the change trends of MRSEI within the study period and in the future. Finally, a zoning management plan for the ecological environment in the study area was proposed based on the coupling of human activity intensity and ecological environment quality. The results show that: ① The assessment results of ecological environment quality by MRSEI and RSEI were consistent to a certain extent. However, MRSEI was more accurate than RSEI in identifying local ecological environment elements, especially in industrial and mining land, construction land, and areas with high vegetation cover, with evaluation results more closely matching the actual surface conditions. ② From 2000 to 2024, the ecological environment quality in Northeast China exhibited a trend of rapid improvement followed by slow degradation. The MRSEI increased by 16.65% from 2000 to 2014 and decreased by 1.75% from 2014 to 2024. Spatially, the study area generally showed a pattern of "high in the east and low in the west." The MRSEI values of growth-oriented and forestry-oriented resource-based cities decreased slowly from 2000 to 2024. Petroleum-oriented resource-based cities had a poor ecological base, with an average MRSEI value lower than that of other types of cities. ③ The change trends of ecological environment quality from 2000 to 2024 were mainly characterized by non-significant improvement, extremely significant improvement, and non-significant degradation. The Hurst index values ranged from 0.06 to 0.95. The area with 0<H<0.5 was 1 031 304.00 km², accounting for 79.18%, among which the area with reverse persistent improvement (improvement turning into degradation) accounted for as high as 59.48%, indicating that most areas that had improved in the past will face the risk of degradation in the future. ④ Based on the coupling of ecological environment quality and human activity intensity, Northeast China was divided into coordinated development zones, protection zones, risk zones, and potential zones for the ecological environment, and differentiated zoning management strategies were proposed to provide references for the implementation of feasible ecological environment protection policies and governance plans in Northeast China.