The Story of a Hitchhiker: Population Genetic Patterns in the Invasive Barnacle Balanus(Amphibalanus) improvisus Darwin 1854

Abstract

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 long-distance 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.

Clone wars: asexual reproduction dominates in the invasive range ofTubastraeaspp. (Anthozoa: Scleractinia) in the South-Atlantic Ocean

“…A decrease in genetic diversity as a result of a small founding population has been previously recorded for several invasive populations (Roman & Darling, 2007; Geller et al, 2008; Johnson & Woollacott, 2015; Wrange et al, 2016; but see Gaither et al, 2010; Gaither, Toonen & Bowen, 2012 for counter-examples). Here, we report excess of heterozygosity for both populations of both species and the presence of up to 100% heterozygous individuals at some loci (Table 1).…”

Seascape genetics and biophysical connectivity modelling support conservation of the seagrass Zostera marina in the Skagerrak–Kattegat region of the eastern North Sea

“…To test for isolation by oceanography (IBO), we correlated genetic distance with minimum oceanographic dispersal probabilities (calculated from the model described above) defined here as oceanographic distance. We used minimum dispersal probability to generate a symmetric matrix of dispersal, because it may arguably be best correlated with (symmetric) geographic and genetic distance (Wrange et al., ). We also correlated directional dispersal probabilities with asymmetric (genetic) migration rates in a Mantel test adapted for asymmetric matrices (Matlab , Mathworks Inc).…”

Refining and expanding global climate change scenarios in the sea: Poleward creep complexities, range termini, and setbacks and surges

“…Such studies could be mined to query if species expansions may have involved overlooked poleward movements, origin‐route‐destination networks that were not recognized as such, retrospectively identify the potential existence of range termini, or, indeed, discover previously unnoticed patterns of setbacks and surges. A few of many examples of regional or global studies that represent a broad range of taxa and that may benefit from retrospective analyses of “climate change biogeography” include the ctenophore (comb jelly) Mnemiopsis leidyi (Bayha et al., ) , the alga Codium fragile fragile (Provan, Booth, Todd, Beatty, & Maggs, ) , the alga Sargassum muticum (Engelen et al., ) , the skeleton shrimp Caprella mutica (Ashton, Willis, Cook, & Burrows, ), the shrimp Palaemon macrodactylus (Lejeusne et al., ), the green crab Carcinus maenas (Carlton & Cohen, ), the isopod Ianiropsis serricaudis (Hobbs et al., ) , the barnacle Amphibalanus improvisus (Wrange et al., ) , the mussel Musculista senhousia (Asif & Krug, ) , the bryozoan Watersipora spp. (Vieira, Jones, & Taylor, ) and the ascidians Styela plicata (de Barros, Rocha, & Pie, ), Ciona spp.…”