Data from: Invasive lumbricid earthworms in North America – different life-histories but common dispersal?

Aim Lumbricid earthworms are invasive across northern North America,
causing notable changes in forest ecosystems. During their range
expansion, they encountered harsher climatic conditions compared to their
native ranges in short time (~400 years). This study investigated if (1)
dispersal barriers, (2) climatic selection, or (3) anthropogenic
activities, i.e. fishing bait disposal, structure the dispersal of
free-living earthworm populations. Location North America, forest habitats
along former Wisconsinan glaciation line Taxon Lumbricus terrestris, L.
rubellus Methods Lumbricus terrestris and L. rubellus co-occur in the same
habitats but differ in ecology and use as fishing bait. Both species were
sampled in five transects ranging from the east to the west coast of
northern North America, including major dispersal barriers, three
different climate zones, and bait shops near sampling locations. Genetic
diversity and structure were compared between the two species, and the
presence of free-living bait shop genotypes was assessed using four
markers (COI, 16S rDNA, 12S rDNA, H3). Results Populations of both species
were genetically diverse with some geographic structure, which was more
pronounced in L. terrestris than in L. rubellus. Common haplotypes were
present in all regions, but locally restricted haplotypes also occurred.
Further, two distinct genetic clades of L. terrestris co-occurred only in
the two most distant transects (Alberta and Minnesota). Genotypes
identical to bait individuals were omnipresent in field populations of L.
terrestris. Main conclusions Genetic diversity was high in both species,
and invasive populations represented a genetic subset of European
earthworms. Geographic and climatic dispersal barriers affected the less
mobile species, L. rubellus, resulting in differences in genetic structure
between the two species. Our results indicate common long-distance
dispersal vectors and vectors affecting only L. terrestris. The roles of
climate and anthropogenic activities are discussed, providing additional
explanations of dispersal and new insights into establishment of invasive
earthworm populations. Keywords biological invasion, colonisation, genetic
clades, agriculture, climate, dispersal barriers