DOI 10.1371/journal.pone.0147082 Understanding the ecological and evolutionary forces that determine the genetic structure and spread of invasive species is a key component of invasion biology. The bay barnacle, Balanus improvisus (= Amphibalanus improvisus), is one of the most successful aquatic invaders worldwide, and is characterised by broad environmental tolerance. Although the species can spread through natural larval dispersal, human-mediated transport through (primarily) shipping has almost certainly contributed to the current global distribution of this species. Despite its worldwide distribution, little is known about the phylogeography of this species. Here, we characterize the population genetic structure and model dispersal dynamics of the barnacle B. improvisus, and describe how human-mediated spreading via shipping as well as natural larval dispersal may have contributed to observed genetic variation. We used both mitochondrial DNA (cytochrome c oxidase subunit I: COI) and nuclear microsatellites to characterize the genetic structure in 14 populations of B. improvisus on a global and regional scale (Baltic Sea). Genetic diversity was high in most populations, and many haplotypes were shared among populations on a global scale, indicating that longdistance dispersal (presumably through shipping and other anthropogenic activities) has played an important role in shaping the population genetic structure of this cosmopolitan species. We could not clearly confirm prior claims that B. improvisus originates from the western margins of the Atlantic coasts; although there were indications that Argentina could be part of a native region. In addition to dispersal via shipping, we show that natural larval dispersal may play an important role for further colonisation following initial introduction.
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Publisher's official version | 28 | 2 Mo | ||
S1 Fig. Schematic figures of modeled scenarios of introductory history for Balanus improvisus. | - | 2 Mo | ||
S1 Table. Information about the spatial and temporal sampling of DNA from Balanus improvisus. | - | 2 Mo | ||
S2 Fig. PCA on summary statistics from the simulated datasets of the four global scenarios and the observed data (yellow) based on; (a) COI sequences and (b) microsatellite loci. | - | 2 Mo | ||
S2 Table. Microsatellite primer information. | - | 2 Mo | ||
S3 Fig. Maximum likelihood phylogenetic tree based on all B. improvisus individuals in the study. | 1 | 136 Ko | ||
S3 Table. Haplotype list with haplotype frequencies (based on COI) for all B. improvisus populations. | 2 | 130 Ko | ||
S4 Fig. Multi-dimensional scaling plot (MDS) based on pairwise FST (not corrected for null alleles) for the different microsatellite loci. | - | 2 Mo | ||
S4 Table. Summary of microsatellite loci results for each population tested. | - | 2 Mo | ||
S5 Fig. Posterior probability of the four ABC modeling scenarios for invasion of B. improvisus on a global scale. | - | 2 Mo | ||
S5 Table. Estimated null allele frequencies for microsatellites. | - | 2 Mo | ||
S6 Fig. Posterior probability of the two scenarios for introduction of B. improvisus into the Baltic Sea. | - | 2 Mo | ||
S6 Table. Pairwise FST between B. improvisus populations based on four microsatellite loci. | - | 2 Mo | ||
S7 Table. Analysis of molecular variance (AMOVA) results on B. improvisus | - | 2 Mo |
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