Seascape factors are responsible for the genetic diversity and connectivity of Ecklonia cava populations

Abstract

Genetic connectivity among marine benthic populations has been essential information for estimating their dispersal capability and the related persistency perspectives. We examined population genetic variability with relation to potential drivers responsible for the genetic clusters of Ecklonia cava populations, a foundation kelp species in the northwest Pacific region. We analyzed eleven local populations along with the South Korean coastline from Jeju Island to Ulleungdo, using microsatellite markers. We found that entire populations studied are genetically divided into two groups: inner (south coast populations) and outer (Jeju Island and Ulleungdo) coastal regions, indicating this segregation pattern corresponds to ocean current patterns around South Korea and the geographical topography. Genetic similarity between the two far most populations (Jeju Island and Ulleungdo) provided a possibility that the dispersal distance of E. cava could be increased by prevailing current. Inter-population genetic structure in the perspectives of the isolation-by-distance (IBD) and isolation-by-environment (IBE) indicated that distance and turbidity gradient are both contributable factors to gene flow of E. cava. However, contrasting results appeared among a few populations, which indicates that effects of these variables could change by geographical range of populations and given oceanographic conditions. This study provides the possibility that gene flow of E. cava is driven by multiple seascape factors (ocean currents, coastal topography, distance and sediments), and the interplay among them at a regional scale, which can be applicable to other kelp species with diverse scales.