Hydro-geomorphological drivers across scales shape the trajectory of coastal wetland restoration

Abstract

Abstract Coastal wetlands provide essential ecosystem services but continue to decline globally, driving demand for effective restoration. Managed realignment, which relocates sea defenses landward to reinstate tidal exchange, is a key nature-based solution for creating self-sustaining wetlands. However, unpredictable restoration outcomes highlight the need for a framework to understand the underlying physical drivers and prioritize sites. Using four decades of satellite data from 69 global sites, we show that over 80% of the restoration projects maintained or expanded wetlands. These trajectories are primarily shaped by regional sediment supply, local tide-relative elevation, and internal tidal creek connectivity. Extending this framework globally, we estimate about 920 square kilometres of wetlands lost since the 1990s could be restored under current physical conditions. Recoverable areas in Asia, the Americas, and Europe exceed the 30% target of the Kunming-Montreal Global Biodiversity Framework. By linking outcomes to multi-scale physical contexts, our results provide a framework for prioritizing restoration and advancing global biodiversity and climate goals.