Dynamic Identification and Evolution of Urban-suburban-rural Transition Zones Based on the Blender of Natural and Humanistic Factors: A Case Study of Chengdu, China

Urban-suburban-rural (U-S-R) zones exhibit distinctive transitional characteristics in interaction between human and nature. U-S-R transition zones (U-S-RTZ) are also highlighting the function diversity and landscape heterogeneity across territorial spaces. As a super megacity in western China, Chengdu’s rapid urbanization has driven the evolution of U-S-R spaces, resulting in a sequential structure. To promote the high-quality spatial development of urban-rural region in a structured and efficient manner, it is essential to conduct a scientific examination of the multidimensional interconnection within the U-S-RTZ framework. By proposing a novel identification method of U-S-RTZ and taking Chengdu, China as a case study, grounded in a blender of natural and humanistic factors, this study quantitatively delineated and explored the spatial evolutions of U-S-RTZ and stated the optimization orientation and sustainable development strategies of the production-living-ecological spaces along the U-S-R gradients. The results show that: 1) it is suitable for the quantitative analysis of U-S-RTZ by established three-dimensional identification system in this study. 2) In 1990−2020, the urban-suburban transition zones (U-STZ) in Chengdu have continuously undergone a substantial increase, and the scale of the suburban-rural transition zones (S-RTZ) has continued to expand slightly, while the space of rural-ecological transition zones (R-ETZ) has noticeably compressed. 3) The landuse dynamics within U-S-RTZ has gradually increased in 1990−2020. The main direction of landuse transition was from farmland to construction land or woodlands, with the expansion of construction land being the most significant. 4) R-ETZ primarily focus on ecological functions, and there is a trade-off relationship between the production-ecological function within the S-RTZ, and in the U-STZ, production-living composite functions are prioritized. This study emphasizes the importance of elastic planning and precise governance within the U-S-RTZ in a rapid urbanization region, particularly highlighting the role of suburbs as landscape corridors and service hubs in urban-rural integration. It elucidates to the practical implications for achieving high-quality development of integrated U-S-R territorial spaces.