Spatial-temporal evolution and driving force analysis of eco-quality in urban agglomerations in China

Urban agglomerations are important spatial carriers of regional economic development, and their ecological quality (EQ) is closely related to economic growth and human development. However, the rapid urbanization in China has generated a series of EQ problems that threaten the sustainable development of the country. Therefore, it is essential to explore changes in EQ for the development of sustainable "human-land" relations in urban agglomerations. Using GIS, GeoDetector, Stepwise multiple regression, and Sen'trend analysis, to reveal the spatial-temporal evolution of EQ in urban agglomerations along with the spatial heterogeneity of its driving forces in China. Results show that: (1) The annual change rate of EQ of urban agglomerations ranges from -0.0312 to 0.0334. Taking the Hu-line as a boundary, the EQ of urban agglomerations is spatially high in the east and low in the west. (2) The Global Moran's I index ranged from 0.740 to 0.687 during the study period, indicating a positive correlation in the EQ spatial distribution. The EQ of urban agglomerations has significant spatial agglomeration, with hot spots concentrated in the eastern region and cold spots in the northwestern region. (3) Main drivers of EQ of urban agglomerations are elevation, population density, nighttime light index, arable land area, real GDP per capita, precipitation, and built-up urban area (q > 10 %). (4) The stepwise multiple regression model spatially reveals that the nighttime light index, built-up urban area land and GDP per capita dominate the ecological quality changes of urban agglomerations, accounting for 73.68 % of the total number of urban agglomerations. This study provides an effective method for assessing spatial-temporal changes of EQ in urban agglomerations, supports scientific decision-making support for the construction of ecological civilization and the development of human-land harmony in urban agglomerations, and promotes the development and construction of "Beautiful China."