Ecosystem health evaluation and driving Force analysis of high groundwater Table Coal-Grain complex area based on remote sensing information

• Constructing an ecological health evaluation index suitable for HGT CGCA. • Enhanced ecological explanation of indicators via EFA weighting. • The PLS-SEM method uncovers the indirect effects of driving factors and interactions within the HGT CGCA. In the eastern coal-rich regions of our country, characterized by flat terrain and fertile land, a typical coal-grain composite area (CGCA) exists. The impacts of underground mining on the surface, in addition to common issues such as ground subsidence and fissures, often lead to the formation of extensive water accumulation. This phenomenon leads to a considerable decrease in the availability of arable land resources within mining regions and has a detrimental impact on the quality of the local eco-environment. This study addresses the lack of a health assessment system for ecosystems in coal-grain composite areas with high groundwater table (HGT). Based on Landsat series data, with a focus on the compounded effects of soil salinization, landscape fragmentation, and air pollution on the degradation of ecosystems in mining regions with HGT. A Pressure-State-Response-Demand (PSRD) framework is proposed to construct a HGT coal mining area composite ecosystem health index (HGT-CEHI). Utilizing partial least squares structural equation modeling (PLS-SEM), this study examines the spatiotemporal evolution trends of ecological quality in HGT CGCA from 1985 to 2020 and explores the underlying driving mechanisms. The results indicated that: (1) Through comparative validation, the HGT-CEHI showed a strong correlation with the traditional Remote Sensing Ecological Index (RSEI) and exhibited a more robust average correlation with its internal component indicators, thereby effectively reflecting the habitat conditions within the study area. (2) From 1985 to 2020, the average value of the HGT-CEHI within the study area fluctuated between 0.559 and 0.634. The ecological environment demonstrated a pattern of “rapid decline, followed by gradual improvement and eventual stabilization.” In the later years, the implementation of ecological engineering management projects resulted in a general enhancement of ecological quality. The areas characterized by excellent ecological quality within the study region were predominantly situated in the southern and western grain production zones. These regions exhibited a pronounced high-high clustering spatial pattern, which demonstrated an increasing trend over time. In contrast, regions exhibiting poor and fair ecological quality were primarily located in urban built-up areas and zones with intensive mining activities in the central part of the study area. These regions displayed a low-low clustering spatial pattern, which indicated a declining trend over time. (3) The analysis of driving mechanisms revealed that the interplay between human activities and ecological factors dominated the spatiotemporal evolution of ecological quality in regions characterized by HGT CGCA. This research offers a new perspective on reconciling the conflict between coal resource development and environmental protection, ensuring that mining activities advance toward sustainable, circular, and green practices.