Introduction history Ambrosia artemisiifolia

In this study, we aim to investigate the contribution of pre-introduction native admixture within North-America as a source to successful invasions of the weed Ambrosia artemisiifolia in Europe and Australia. We study this mechanism alongside the more well-known scenarios of multiple introductions and bridgehead invasions (secondary introduction sourced from an invaded range). To do this, we have identified 10,100 loci using genotype-by-sequencing. We compare complex invasion scenarios using approximate Bayesian computation together with Random Forest scenario evaluation (ABC-RF). We believe our findings are of great significance to the research field of invasion biology, with implications for fundamental theory on rapid adaptation as well as the formulation of management strategies.