Résumé
Over the last 15 years studies on invasion
genetics have provided important insights to unravel
cryptic diversity, track the origin of colonizers and
reveal pathways of introductions. Despite all these
advances, to date little is known about how evolutionary
processes influence the observed genetic
patterns in marine biological invasions. Here, firstly
we review the literature on invasion genetics that
include samples from European seas. These seas
constitute a wide array of unique water masses with
diverse degrees of connectivity, and have a long
history of species introductions. We found that only a
small fraction of the recorded introduced species has
been genetically analysed. Furthermore, most studies
restrict their approach to describe patterns of cryptic
diversity and genetic structure, with the underlying
mechanisms involved in the invasion process being
largely understudied. Secondly, we analyse how genetic, reproductive and anthropogenic traits shape
genetic patterns of marine introduced species. We
found that most studies reveal similar genetic diversity
values in both native and introduced ranges, report
evidence of multiple introductions, and show that
genetic patterns in the introduced range are not
explained by taxonomic group or reproductive strategy.
Finally, we discuss the evolutionary implications
derived from genetic patterns observed in non-indigenous
species. We identify different scenarios that are
determined by propagule pressure, phenotypic plasticity
and pre-adaptation, and the effects of selection
and genetic admixture. We conclude that there is a
need for further investigations of evolutionary mechanisms
that affect individual fitness and adaptation to
rapid environmental change.