Multi-Decadal Evolution Pattern and Trends of the Central Coastline of Jiangsu Province: Implications for Future Coastal Management

As an important geographical component at the boundary between land and ocean, the coastline serves as a key indicator reflecting coastal erosion and ecosystem variations. The central Jiangsu coast is a typical muddy coast, and against the backdrop of global climate change and large-scale coastal development, its coastal evolution is complex. In this study, we analyzed the patterns and trends in the evolution of Jiangsu’s coastline using remote sensing imagery from 1984 to 2024. The result indicated that the coastline length in central Jiangsu exhibits a trend of ‘initial continuous decrease followed by recovery growth.’ The coastline peaked at approximately 586.5 km in 1988 and then shortened to a minimum of about 365.2 km in 2015, after which it began to recover. Throughout the study period, the spatiotemporal changes in the coastline displayed a pattern with the Sheyang Estuary as the boundary, characterized by ‘more erosion in the north and more accretion in the south.’ The most severely eroded section was near the Fansheng Estuary, retreating by about 1412.18 m, whereas the most significant sedimentation occurred north of Fangtang Estuary, advancing by about 11,129.78 m toward the sea, with appositional uncertainty (RMSE) of ±15.6 m based on independent validation. The coastline evolution process was classified into seven patterns, with clear differences in spatial distribution and state transitions among them. With the sediment reduction, rising sea levels, and increased frequency of extreme marine storms has heightened the risk of coastal erosion. Therefore, measures such as comprehensive protection, restoration, and management of muddy coasts, scientific promotion of sedimentation, and appropriate reclamation design should be implemented.