Marine Phytogeography of the Juan Fernandez Archipelago: A New Assessment

Abstract

A new assessment of the geographic affinities of the marine algae of the Juan Fernandez Archipelago indicates a flora with a small number of species and very high endemism (about 30%) as compared to other oceanic islands of similar age, size, origin, and abiotic conditions. The flora also contains many widely distributed species (45%) and a small group of species with circumpolar-subantarctic affinities (about 13.5% of the flora). The potential algal species sources for this flora seem to be distant localities in the southern Pacific, including the southern tip of South America, southern Australia, New Zealand, and several subantarctic islands. Considering effective dispersal distances of marine benthic algae, the Juan Fernandez Archipelago appears as more isolated than Easter Island, which previously was supposed to be the most isolated point in the Pacific basin. An analysis of the endemic components suggests that there has been speciation but no radiation in these islands. Some species originating in the archipelago might have migrated across the Pacific to continental South America, perhaps via El Nino/Southern Oscillation (ENSO).