Measurement of rural multifunctional transformation of metropolitan area and implications for high-quality development: a case study of Chengdu-Chongqing Economic Circle, China

The suburbs surrounding metropolitan areas are the priority area for urban-rural integration development where functional optimization is essential to reconcile growing urban demands with sustainable rural development. Rural functions are changing substantially and vary significantly across areas in the practice of high-quality urban-rural integration development era. How to make use of the advantages of different rural functions and achieve optimized combination of functions are actual problems that urgently need to be solved. The paper analyzed the process of urban-rural integration through the identification of urban-rural integration interfaces and evaluated the multifunctional transformation of rural areas in the Chengdu-Chongqing Economic Circle (CCEC) with a fixed weight evaluation model. The differences in rural functions analyzed with the Theil index reveals the characteristics and sources of differences in the "production-living-ecology-culture" functional areas in the CCEC. The research results show that: (1) The spatial distribution characteristics of rural functions in the CCEC are obvious, and agricultural production clusters dominate the Chengdu Plain and eastern Chongqing, contrasting with ecological conservation zones along the Yangtze River system, while cultural heritage hubs concentrate in economically vibrant tourism corridors. (2) The overall regional differences in rural functions are mainly due to intra-regional differences; in terms of the contribution rate, the contribution rate of intra-regional differences in agricultural production, ecological conservation, and cultural heritage functions is much larger than that of inter-regional differences, whereas the inter-regional differences in human living functions are larger than those of intra-regional differences. (3) Based on the research results, the study area is divided into 14 functional types, which can provide scientific basis for improving the spatial layout and high-quality development of rural functions in the CCEC. These insights advance theoretical understanding of mountainous-urban transitional areas while informing practical strategies for high-quality integrated development.