The Integration of Land Use Planning and the Varied Responses of Coupled Human–Natural Systems: A Case Study of Changning County in Southwest China

An urban–rural–natural imbalance is evident; investigating the spatiotemporal evolution of the transitional geo-space (TG) between them facilitates the integration of urban–rural land use planning. In this study, we proposed a complex system model to explore the interactive dynamics between the social–economic systems and natural ecosystems of Changning County, Southwest China, with the TG being identified and classified across the two systems. Based on a three-dimensional “direction–speed–pattern” framework, we further quantified production–living–ecological space (PLE) changes and examined the impacts of these changes on the TG from 2000 to 2022. The results are as follows: (1) The TG was classified into five categories that were stratified according to the coupling intensity and orientation of the socioeconomic system and natural ecosystems in Changning County. (2) The transition type with the most complex socio-ecological coupling was the type of semi-socioeconomic process–semi-natural ecological process, occupying 32.6% (309.4 km 2 ) of the county’s total area in 2000 and demonstrating the most pronounced spatial dynamics, exhibiting a reduction of 78.6 km 2 during the study period. (3) Negative impacts on TG dynamics were observed for the conversion of ecological space into agricultural production space ( p < 0.01; R 2 > 0.24) and the dynamic degree of PLE transformations ( p < 0.01; R 2 > 0.13). (4) The impacts of trends in PLE on the TG varied significantly across temporal phases, whereas the CONTAG index exhibited consistently non-significant effects throughout all study periods. This study provides a new insight into understanding the optimization of spatial development patterns in urban–rural–natural regions and offers theoretical support for the governance of national land space and high-quality economic and social development in mountainous areas.