Analysis of the Heterogeneity in the Spatial Network of Land Use Carbon Emissions and Ecosystem Services: A Case Study of the Chang-Zhu-Tan Urban Agglomeration

Urban agglomerations are crucial for promoting the balanced development of carbon emissions (CE) and ecosystem services (ES). However, a structural imbalance exists between land use carbon emissions (LUCE) and ES, compounded by the absence of standardized measurement frameworks and clear governance strategies. This research uses the Chang-Zhu-Tan urban agglomeration as a case study to establish a spatial association network linking LUCE and ES, based on multi-source data from 2010 to 2023. Centrality metrics are utilized to assess connectivity, accessibility, and channel functions. To identify key factors, three heterogeneity indices are developed for evaluation and driving factor analysis. The findings are as follows: (1) Both LUCE and ES networks display corridor-like and cross-domain connections, but with asymmetric node structures. The degree centrality of the LUCE-Network increased from 0.16 to 0.29, while that of the ES-Network rose from 0.16 to 0.23. (2) Heterogeneity was generally positive in the initial stages but turned negative by 2023, signifying a shift from a dominance of carbon networks to one dominated by ecological networks. The positive bias is concentrated along primary urban corridors and boundaries, whereas negative bias is observed in green zones and mountainous water networks. (3) The heterogeneity is influenced by spatial layout, natural environments, and human activities. Among the driving factors, the proportion of built-up land (X11) grew from 0.0187 in 2010 to 0.1500 in 2023, intensifying the disparity between LUCE and ES networks. The urbanization rate (X7) surged to 0.1558 in 2023, up from 0.0761 in 2010, which contributed to increased CE and heightened demand for ES. Forest cover (X10) progressively strengthened the ES-Network, reaching 0.1378 by 2023. In general, urbanization and land use shifts have significantly altered the spatial organization of LUCE and ES. (4) Based on structural correction and process coupling, a collaborative pathway is proposed: stringent control of new developments and rehabilitation of existing structures in high positive-bias corridors and hubs, with a focus on ecological and river-lake connectivity projects; extensive restoration and expansion of green zones and mountainous water networks; reduction of single-channel dependency through public transport prioritization, energy efficiency upgrades, clean energy transitions, and multimodal transport strategies; and the establishment of a threshold-monitoring-assessment system through heterogeneity indices and key variables. This research suggests transforming average coupling assessments into actionable diagnostics for network structural differences and enables the identification of driving factors and the implementation of collaborative pathways, offering a replicable framework for low-carbon and ecological governance in urban agglomerations.