Coastal tidal flats in East China's Radial Sand Ridges have been changing due to human activities. By analyzing satellite images from 1975 to 2017, researchers found that the tidal flat area has decreased by 992 km2, mainly due to land reclamation. The low tidal flats are eroding, especially in the Northern and Southern Swing areas, while the high tidal flats are growing slowly. This erosion is linked to a decrease in sediment supply. These findings will help local managers plan for future land needs and rising sea levels.