title: The oceanic concordance of phylogeography and biogeography: a case study in Notochthamalus.
abstract: Dispersal and adaptation are the two primary mechanisms that set the range distributions for a population or species. As such, understanding how these mechanisms interact in marine organisms in particular - with capacity for long-range dispersal and a poor understanding of what selective environments species are responding to - can provide useful insights for the exploration of biogeographic patterns. Previously, the barnacle Notochthamalus scabrosus has revealed two evolutionarily distinct lineages with a joint distribution that suggests an association with one of the two major biogeographic boundaries (~30°S) along the coast of Chile. However, spatial and genomic sampling of this system has been limited until now. We hypothesized that given the strong oceanographic and environmental shifts associated with the other major biogeographic boundary (~42°S) for Chilean coastal invertebrates, the southern mitochondrial lineage would dominate or go to fixation in locations further to the south. We also evaluated nuclear polymorphism data from 130 single nucleotide polymorphisms to evaluate the concordance of the signal from the nuclear genome with that of the mitochondrial sample. Through the application of standard population genetic approaches along with a Lagrangian ocean connectivity model, we describe the codistribution of these lineages through a simultaneous evaluation of coastal lineage frequencies, an approximation of larval behavior, and current-driven dispersal. Our results show that this pattern could not persist without the two lineages having distinct environmental optima. We suggest that a more thorough integration of larval dynamics, explicit dispersal models, and near-shore environmental analysis can explain much of the coastal biogeography of Chile.
authors.affiliation: College of Biological Sciences University of California Davis California 95616.
authors.forename: Christine
authors.initials: C
authors.lastname: Ewers-Saucedo
authors.affiliation: Institute for the Study of Earth, Ocean, and Space University of New Hampshire Durham New Hampshire 03824.
authors.forename: James M
authors.initials: JM
authors.lastname: Pringle
authors.affiliation: Departamento de Geofisica Universidad de Concepción Concepción Chile.
authors.forename: Hector H
authors.identifier: 0000-0002-0131-6627
authors.initials: HH
authors.lastname: Sepúlveda
authors.affiliation: Odum School of Ecology University of Georgia Athens Georgia 30602.
authors.forename: James E
authors.initials: JE
authors.lastname: Byers
authors.affiliation: Estación Costera de Investigaciones Marinas Las Cruces and Center for Marine Conservation Pontificia Universidad Católica de Chile Casilla 114D Santiago Chile.
authors.forename: Sergio A
authors.initials: SA
authors.lastname: Navarrete
authors.affiliation: Odum School of Ecology University of Georgia Athens Georgia 30602; Department of Genetics University of Georgia Athens Georgia 30602.
authors.forename: John P
authors.initials: JP
authors.lastname: Wares
keywords: Biogeography; Chile; Pacific Ocean; connectivity; population genetics