Linking seascape with landscape genetics: oceanic currents favour colonisation across the Galapagos Islands by a coastal plant

Coastal plants are terrestrial organisms likely to be specialized in sea dispersal (thalassochorous species), for which the sea acts as a long-distance dispersal vector favoring wide distributions and connecting distant populations. However, few studies have statistically assessed the role of sea currents in modulating gene flow and species distribution of terrestrial organisms. Using a Galapagos coastal plant (Cryptocarpus pyriformis Kunth) as a study case, we show that thalassochorous plants really have a good dispersal ability by sea, resulting in high inter-island gene flow modulated by direction and speed of sea currents.