Evolutionary patterns and the hierarchical spatial system of modern human-Earth systems

The spatial organization of urban-rural systems is fundamentally shaped by the agglomeration and diffusion effects inherent in human-Earth processes, giving rise to distinct gradient-based and hierarchical structures. Understanding the complexity of these interactions and their multidimensional drivers is essential for deciphering the mechanisms of integrated urban-rural development. Here, we apply a novel hierarchical spatial system framework based on the human-Earth system, combining social network analysis and multi-level modeling, to examine the evolution of the socio-spatial structure in the Beijing-Tianjin-Hebei region from 2000 to 2020. We developed a comprehensive evaluation system spanning economic, social, environmental, and infrastructural dimensions to characterize spatial patterns across multiple network levels, including city clusters, metropolitan areas, municipal-counties, towns, and villages. Our analysis reveals three key findings: First, the density of foundational network connections increased significantly, reflecting a trend toward spatial concentration driven by policy-led regional integration. Second, network structures at the city-cluster and metropolitan scales exhibited a pattern of “initial expansion followed by convergence”, accompanied by notable shifts in their spatial centers of gravity. In parallel, differentiated patterns of agglomeration and expansion were evident in the township- and village-level networks of Baoding, Tangshan, and Handan, while village-level networks in Anxin, Quyang, and other locations demonstrated distinct developmental trends. Third, community structures demonstrated strong functional homophily and interactive cohesion across multiple dimensions, with metropolitan and township communities undergoing restructuring that reflects a reconfiguration of cross-level influence and functional coupling. Spatially, the system manifests as a gradient structure of interwoven point, line, and area networks, establishing a mechanism for functional differentiation and transmission from rural to urban areas. This study provides theoretical foundations and methodological support for understanding the spatial organization logic of integrated urban-rural development, offering practical reference value for advancing regional coordination and rural revitalization in a scientifically informed manner.