Coupling coordination and spatial differentiation between urbanization and eco-environment: case study of Ya'an, China

The rapid urbanization of Ya'an has brought about a series of environmental issues. By referring to the physical coupling model and using the data from 2010 to 2019, this paper establishes a coupling coordination model of the urbanization and eco-environment in Ya'an. First, the entropy method was used to calculate the weight of each index of urbanization and eco-environment systems. Then, the comprehensive urbanization level of Ya'an was calculated using four indexes: economic, population, spatial and social urbanization. The eco-environment evaluation index system included three main indexes: eco-environment level, pressure and response. Finally, coupling coordination model was used to determine the degree of coupling and coordination between urbanization and the eco-environment, and the spatial correlation of the coordination degree between districts and counties in Ya'an was analyzed. The results show that: (1) economic urbanization (37.76%) and eco-environment pressure (40.50%) made the most significant contributions to the urbanization and eco-environment subsystems, respectively. This shows that economic factors are the most significant contributors in promoting the development of urbanization. As it is very important for Ya'an to reduce environmental pollution and the pressure on the eco-environment, these findings suggest that more attention should be paid to economic development and environmental protection when formulating and implementing policies. (2) The degree of coupling coordination between urbanization and the eco-environment has increased every year, from moderate imbalance to high coordination. The overall development of spatial autocorrelation from positive to negative suggests that Ya'an should strengthen the interregional cooperation.