Multiple introductions, admixture and bridgehead invasion characterize the introduction history of Ambrosia artemisiifolia in Europe and Australia

Lotte A. van Boheemen, Eric Lombaert, Kristin A. Nurkowski, Bertrand Gauffre, Loren H. Rieseberg, Kathryn A. Hodgins

Research output: Contribution to journalArticleResearchpeer-review

86 Citations (Scopus)


Admixture between differentiated populations is considered to be a powerful mechanism stimulating the invasive success of some introduced species. It is generally facilitated through multiple introductions; however, the importance of admixture prior to introduction has rarely been considered. We assess the likelihood that the invasive Ambrosia artemisiifolia populations of Europe and Australia developed through multiple introductions or were sourced from a historical admixture zone within native North America. To do this, we combine large genomic and sampling data sets analysed with approximate Bayesian computation and random forest scenario evaluation to compare single and multiple invasion scenarios with pre- and postintroduction admixture simultaneously. We show the historical admixture zone within native North America originated before global invasion of this weed and could act as a potential source of introduced populations. We provide evidence supporting the hypothesis that the invasive populations established through multiple introductions from the native range into Europe and subsequent bridgehead invasion into Australia. We discuss the evolutionary mechanisms that could promote invasiveness and evolutionary potential of alien species from bridgehead invasions and admixed source populations.

Original languageEnglish
Pages (from-to)5421-5434
Number of pages14
JournalMolecular Ecology
Issue number20
Publication statusPublished - 1 Oct 2017


  • admixture
  • Ambrosia artemisiifolia
  • approximate Bayesian computation (ABC)
  • bridgehead invasion
  • introduction history
  • random forests

Cite this