Study on the spatial-temporal patterns and evolution characteristics of ecological security based on dynamic evaluation in the Three Gorges Reservoir Area

Monitoring ecological security in the Three Gorges Reservoir Area (TGRA) is the prime objective of the ecosystem research on the Yangtze River basin. The comprehensive dynamic evaluation model of ecological security based on the "Pressure-State-Benefit" and four dimensions of "time-space" was designed in this study. Furthermore, comparative analysis and coefficient of sensitivity (CS) were used to verify the rationality and scientificity of this model. This study interpreted and determined the land use data of the TGRA from 2000 to 2020. The coupling coordination degree model, the spatial correlation model and the cluster analysis model assisted in determining the spatial pattern distribution and dynamic interaction characteristics of ecological security at the grid-county-watershed scales in the TGRA. The analytical results demonstrated that the ecological security index (ESI) in the TGRA was generally not very high due to resource constraints and background environmental conditions. The ESI was significantly clustered in space. The initial impoundment of the TGRA significantly impacts ecological security. Implementing dot-shaped ecological restoration projects has greatly improved unsafe and low-security state areas. However, the non-significant growth in the high-security state level region can be attributed to the lack of overall planning and implementation scale. The ecological pressure caused by economic and social development in the main urban area has led to a substantial decline in regional ecological benefit. Therefore, it is necessary to balance the coordinated development relationship between economic-social and ecological benefit in the region. These findings will provide references and supportive data for environmental protection and ecological restoration in the TGRA.