Richard Kazimierz Frank Unsworth, Benjamin Lawrence Hopper Jones , Chiara Bertelli, Lucy Coals, Leanne Cullen-Unsworth, Anouska Mendzil, Sam Rees, Flo Taylor, Bettina Walter, Alison Evans

It is unequivocal that the world has lost a significant proportion of its seagrass, and although glimmers of hope exist, losses continue with many ongoing negative trajectories. First and foremost, we need to put the world on a global pathway to seagrass net gain. Conservation of what remains must be a priority, but we need to increase coverage at rates unlikely to be achieved naturally; large-scale active restoration is required to fill this gap. Novel finance mechanisms aligned to the climate emergency and biodiversity crises are increasingly leading to larger-scale restoration projects. However, no clear framework exists for developing or prioritising approaches. With seagrass restoration expensive and unreliable, rigorous guidance is required to improve effectiveness and ensure it is cost-effective, so that projects can begin to transform whole coastlines. Building on current evidence from both terrestrial and marine sources, here we apply the ‘10 golden rules’ concept, first outlined for reforestation and later applied to coral reefs, to seagrass restoration. In doing so, we follow the International Principles and Standards for the Practice of Ecological Restoration and view seagrass restoration in a broad context, whereby regeneration can be achieved by either planting or by enhancing and facilitating natural recovery. These rules somewhat differ from those on reforestation and coral reef restoration, principally due to the relative immaturity of seagrass restoration science compared to these comprehensively researched ecosystems. These 10 golden rules for seagrass restoration are placed within a coupled social-ecological systems (SES) context and we present a framework for conservation more broadly, to achieve multiple goals pertaining to people, biodiversity and the planet.