Mangrove genera influence bed shear stress and coastal protection ecosystem services

• Genus morphology influences coastal protection provided by mangroves • Within-genus variability in morphology drives differences in accretion • Bed shear stress may be a reliable proxy for sediment accretion in mangroves • Small stature of Avicennia outperforms other genera when canopies are submerged • Semi-arid and temperate short mangroves have higher accretion potential than others Mangrove forest structure varies with species and climate, influencing the provision of ecosystem services. Most studies on coastal protection services assess wave attenuation, few examine sediment accretion, despite its importance for mangrove persistence under sea level rise (SLR). This study examines how different mangroves influence sediment accretion. We modelled how variation in mangrove structure influenced sediment accretion and validated results against a global dataset of sediment accretion. Of the three dominant seaward fringing genera, Avicennia reduced bed shear stress more than Rhizophora and Sonneratia, promoting higher levels of sediment accretion. The shear stress reduction by Avicennia increased with tree density. For Avicennia, bed shear stress reduction and thus sediment accretion were strongly positively linked to the surface area of inundated roots, although this varied among climate zones. Variation in bed shear strength among mangrove genera indicates a role for biodiversity in influencing resilience to SLR and the provision of other ecosystem services.