Anthropogenic transport of species across native ranges: unpredictable genetic and evolutionary consequences

Abstract

Human activities are responsible for the translocation of vast amounts of organisms, altering natural patterns of dispersal and gene flow. Most research to date has focused on the consequences of anthropogenic transportation of non-indigenous species within introduced ranges, with little research focusing on native species. Here, we compared genetic patterns of the sessile marine invertebrate, Ciona intestinalis, which has highly restricted dispersal capabilities. We collected individuals in a region of the species' native range where human activities that are known to facilitate the artificial spread of species are prevalent. Using microsatellite markers, we revealed highly dissimilar outcomes. First, we found low levels of genetic differentiation among sites separated by both short and large geographical distances, indicating the presence of anthropogenic transport of genotypes, and little influence of natural geographical barriers. Second, we found significant genetic differentiation in pairwise comparisons among certain sites, suggesting that other factors besides artificial transport (e.g. natural dispersal, premodern population structure) may be shaping genetic patterns. Taken together, we found dissimilar patterns of population structure in a highly urbanized region that could not be predicted by artificial transport alone. We conclude that anthropogenic activities alter genetic composition of native ranges, with unknown consequences for species' evolutionary trajectories.

Secondary contacts and genetic admixture shape colonization by an amphiatlantic epibenthic invertebrate

“…In contrast to the Sweden populations, individuals from England, Jersey and France formed a relatively homogeneous genetic cluster in both ADMIXTURE and DAPC analyses (Figures 2-4). Earlier work showed that samples from these locations were subdivided into two genetic groups (Hudson et al, 2016), but this differentiation was weaker than what we found between samples from deep Sweden and those from England, Jersey and France. The native range of C. intestinalis has been previously described as the northeast Atlantic (e.g., Bouchemousse, Bishop, et al, 2016a;Hudson et al, 2016), and here, we show that this range comprises most of the genomic differentiation among populations, with more complex demographic histories among populations along the northeast coast of the Atlantic than the northwest coast.…”

“…This propensity to foul can lead to negative economic and ecological impacts when this species is found in aquaculture facilities (Fitridge et al, 2012;Lutz-Collins, Ramsay, Quijón, & Davidson, 2009;Rius et al, 2011). Consequently, most research studying the extensive distribution of C. intestinalis has been performed considering individuals found on artificial structures (e.g., Bouchemousse, Bishop, et al, 2016a;Bouchemousse, Liautard-Haag, Bierne, & Viard, 2016c;Hudson et al, 2016;Zhan, Macisaac, & Cristescu, 2010). This has led to a good understanding of the distribution of C. intestinalis on artificial structures, but there is still limited knowledge of the relative importance of natural and artificial habitats for the spread and establishment of this species in new areas.…”

Oceanographic barriers to gene flow promote genetic subdivision of the tunicate Ciona intestinalis in a North Sea archipelago

“…This is high but similar to earlier studies of C. intestinalis (Zhan et al 2012; Hudson et al 2016). Further corroborating earlier studies, we also found strong heterozygote deficiencies at some loci.…”

Population genomics of the introduced and cultivated Pacific kelp Undaria pinnatifida: Marinas—not farms—drive regional connectivity and establishment in natural rocky reefs

“…pinnatifida at a regional scale. Similar chaotic connectivity patterns have been found in other marine NIS, such as the tunicate Styela clava (Dupont et al., 2009; Goldstien, Schiel, & Gemmell, 2010), as well as in native species established in marinas like the ascidian Ciona intestinalis (Hudson, Viard, Roby, & Rius, 2016), associated with boating activities. Floating pontoons and leisure boats, docking in the marinas, etc., are providing new habitats to many and diverse NIS taxa (e.g., bryozoans (Marchini, Ferrario, & Minchin, 2015), caprellids (Ros et al., 2013)) and are pathways of NIS spread (Clarke Murray, Pakhomov, & Therriault, 2011; Mineur, Johnson, & Maggs, 2008).…”