Intercity Transportation and Ecological Space: A Multi-Scale Analysis of the Guangdong–Hong Kong–Macao Greater Bay Area

Against the backdrop of continuous advances in economic globalization and urbanization, analyzing the spatial associations and potential pathways through which transportation development affects ecological space is of substantial significance. However, the multi-scale spatial associations between intercity transportation systems and the ecological space of urban agglomerations remain unclear, limiting the further development of research on the relationship between transportation systems and ecological space. Therefore, this paper characterizes multi-scale spatial associations of intercity transportation systems with the ecological space of urban agglomerations, using landscape pattern analysis and a multi-scale geographically weighted regression (MGWR) model. This study selects the Guangdong–Hong Kong–Macao Greater Bay Area in China as the study area. The key findings of this study are as follows. (1) Ecological indicators surrounding transportation trunk lines exhibit a significant distance-decay gradient. In general, the closer sites are to transportation trunk lines, the lower the proportion of ecological land and the greater the landscape fragmentation, while landscape connectivity is reduced. In addition, relative to roads, railways generate stronger negative associations with landscape integrity and connectivity. (2) The association between road density and ecological space exhibits substantial differences across analytical units. As the analytical unit becomes finer-grained, the direction of spatial association gradually shifts from unidirectional negative associations to a complex pattern of interwoven positive and negative associations. (3) The association between road density and ecological space exhibits substantial spatial heterogeneity. At the county scale, road density exhibits a significantly weaker negative spatial correlation with ecosystem quality in core metropolitan areas than in peripheral cities. At the grid scale, road density exhibits local positive associations with ecosystem quality. This study not only provides new empirical evidence for resolving the long-standing academic debate between the benefit-oriented perspective and the harm-oriented perspective but also lays a foundation for the coordinated development and spatial governance of the transportation–ecological space nexus.