Improved urbanization-vegetation cover coordination associated with economic level in port cities along the Maritime Silk Road

The sustainability of port cities affects the competitiveness of their hinterland in international shipping and maritime trade, however, the coordinated relationship between urbanization and ecological environment in port cities has received less attention. In this study, we quantitatively analyzed the urban expansion process and vegetation cover changes in 44 port cities along the Maritime Silk Road during 2000–2020 based on multi-source remote sensing data. Adopting the urbanization-vegetation cover index (UVCI), we measured the coordination relationship between urban expansion and vegetation cover and the dynamics during 2000–2020. The results found that all port cities experienced dramatic development from 2000 to 2020, with an average increase in artificial surface area of 127.81%. The 63.64% of port cities experienced increased vegetation cover, thus the overall UVCI in the port city moved toward a more coordinated and sustainable pattern with significant heterogeneity at the economic levels. High-economy port cities have generally become more coordinated, while most low- and medium-economy cities still face challenges of conflicting urban expansion and ecological preservation. This study contributes to the development of government policies that support green and sustainable urban development in port cities, and provides insights for rationalizing development policies in port cities worldwide.