Impacts of the kelp conveyor hypothesis on population genetics of subtidal red algae (Rhodophyta)
University of New Brunswick
Endemic species of Haida Gwaii are commonly attributed to populations persisting in glacial refugia; however, kelp rafting has been recently proposed to explain the disjunct distributions of macroalgal species previously considered endemic to Haida Gwaii. Using mtDNA from five predominantly subtidal species and three predominantly intertidal species of red algae, this study tested the hypothesis that disjunct distributions between Haida Gwaii and California are caused by kelp rafting of subtidal, non-buoyant species. In support of this hypothesis, genetic connectivity of populations in California and Haida Gwaii was greater in subtidal species than intertidal species and allele frequencies suggest direct migration of subtidal species from Haida Gwaii to California. Interestingly, unique Haida Gwaii alleles in subtidal and intertidal species indicate long residence times for some populations, suggesting glacial refugia and kelp rafting may be jointly responsible for disjunct distributions observed at the population level for macroalgae along this coast.