Seagrasses provide an important ecosystem service by creating a stable erosionāresistant seabed that contributes to effective coastal protection. Variable morphologies and life history strategies, however, are likely to impact the sediment stabilisation capacity of different seagrass species. We question how opportunistic invasive species and increasing grazing by megaherbivores may alter sediment stabilisation services provided by established seagrass meadows, using the Caribbean as a case study.