Larger distribution ranges of seagrasses towards the equator

Aim: The description of species' ranges provides biogeographical information to explain fundamental macroecological and evolutionary processes. In this study, we investigated the Rapoport's rule for the world's seagrasses, that is, whether the range extent of seagrasses increases from the tropics to the poles.Location: Global.Taxon: Seagrasses.Methods: We examined whether four range geographical metrics: the extent of latitudinal and longitudinal ranges, total distribution area (Km2) and the number of marine ecoregions encompassed by seagrass species, changed according to their latitudinal distribution midpoints.Results: Seagrasses have larger distribution ranges, as indicated by all geographical metrics, close to the equator in both hemispheres, supporting the inverse of the Rapoport's biogeographical pattern.Main Conclusions: The larger distribution ranges of seagrasses towards equatorial regions may be attributed to their origins during warm geologic periods, and the subsequent longer climatic stability in tropical areas leading to climate niche conservatism constraining seagrass evolution.