Theory and improvement pathway of urban ecological carrying capacity: historicity, nexus and nonlinearity

How to coordinate urban sustainable development with urban ecological carrying capacity is not only related to destiny of a city, but also related to whether surrounding areas can successfully achieve a goal of high-quality and sustainable development．In this study concept and misconceptions of ecological carrying capacity are reorganized, and characteristics of ecological carrying capacity are summarized from aspects of system composition, carrying objects, carrying features of supply and demand, environmental impact and theoretical basis．Differences between ecological carrying capacity and resource carrying capacity, environmental carrying capacity and other composite carrying capacity are clarified．Existing evaluation methods of ecological carrying capacity is used to propose a nexus framework of correlations among ecological carrying capacity, resource carrying capacity and environmental carrying capacity．Correlation methods are developed to quantify coupling and movement of ecological carrying capacity．It is found that coordination between horizontal (sectoral) and vertical (cross-scale) aspects should be fully considered when government policy is adopted to improve ecological carrying capacity．