Divergent Responses of Ecological Quality Under Various Periods of Urbanization in the Yangtze River Basin of China

Ecological security describes the capacity of ecosystems to maintain their integrity and resilience under anthropogenic and natural pressures. The Yangtze River Basin plays a critical role in China’s ecological security and economic growth. In this study, the spatiotemporal patterns and drivers of ecological quality indexes (EQIs) from 2000 to 2018 in the Yangtze River Basin were explored using spatial trend analysis and importance analysis. The results demonstrated that the EQI changes in the Yangtze River Basin showed an overall downward trend during the study period, while the regions with significant increases in EQIs were concentrated in the southwestern basin. Moreover, the differences between mega cities and ordinary cities were analyzed. The decline rate of the EQIs in mega cities was relatively smaller than that in ordinary cities. Additionally, anthropogenic drivers, including global artificial impervious area (GAIA) rate, population density, and gross domestic product (GDP), were identified as factors affecting environmental quality. Among them, the increase in the proportion of impervious areas was the most significant driver of environmental degradation in both mega cities and ordinary cities. The relatively important ecological driving factors varied in the two types of cities. This study provides a theoretical basis and decision support for green development in the Yangtze River Basin. In the future, policymakers should focus on the dominant factors affecting ecological quality and develop appropriate environmental management measures.