Coupling coordination analysis and spatiotemporal heterogeneity between urbanization and ecosystem health in Chongqing municipality, China

Rapid urbanization has seriously disturbed the structure and function of ecosystems and caused many eco-environmental problems, in turn, these problems also reduce the quality of urbanization and threaten the sustainable development of urban. Currently, most studies only focus on the impact of urbanization on ecosystem components (i.e., structure, functions or services), few studies have explored the coordination and spatiotemporal heterogeneity between urbanization and ecosystem health from a systematic view. Therefore, in viewing of this, this study integrated coupling coordination degree model (CCDM) and geographically and temporally weighted regression (GTWR) to measure the interaction relationship and spatiotemporal heterogeneity between urbanization and ecosystem health (UAEH) in Chongqing at the county scale from 1997 to 2015. Results showed that: 1) the degree of coordination between UAEH in Chongqing increased gradually from 1997 to 2015, developed from the moderately unbalance stage to moderately balance stage, and experienced a transition from urbanization lag to ecosystem health lag. Moreover, the coupling coordination degree showed a decreased spatial trend from the western to the eastern of Chongqing. 2) The restriction effect between UAEH gradually weakened from 1997 to 2015, and the synergistic effect between them gradually strengthened. Additionally, the interaction between UAEH tended to converge, and the negative effects between UAEH were mainly distributed in the central and western of Chongqing. In these area, population urbanization aggravated the deterioration of the natural ecosystem, in turn, the decline of ecosystem vigor and resilience also restricted the sustainable development of urbanization. Finally, this study also puts forward some corresponding policy recommendations based on each region's coupling type.