Predicting the Location of Current-Driven Biogeographic Boundaries in the Coastal Ocean

In the coastal ocean, species range boundaries tend to cluster in specific alongshore locations. We used estimates of larval dispersal from a global current model coupled with a simple population model to predict where these clusters are likely to arise due to current-driven larval transport. The locations of the predicted boundary clusters are significantly correlated to observed locations of biogeographic boundaries in the coastal ocean, suggesting that currents play an important role in setting the location of biogeographic boundaries in many locations throughout the coastal ocean. Understanding how currents spatially structure species range boundaries is essential to predicting how species ranges will shift in response to a changing climate and for setting conservation and management goals to respond to those changes.

To predict the locations of species range boundary clusters, we tracked simulated larval particles within 1/12° global velocity fields obtained from the operational Mercator global ocean analysis and forecast system (PSY4V3R1, distributed by the E.U. Copernicus Marine Environmental Monitoring Service) and used the trajectories of these particles to generate estimates of current-driven larval dispersal in the global coastal ocean. We used connectivity matrices from these dispersal estimates in a simple two-species population model which was used to find the location of range boundaries.