Phylogeography and the Description of Geographic Patterns in Invasion Genomics

Abstract

Phylogeography is an integrative discipline that aims to understand the geographic ordination of genotypes. In recent decades, phylogeographic approaches have been used to enhance our understanding of both biogeography and landscape genetics across a variety of spatial and temporal scales. By definition, species studied using these approaches need to meet certain assumptions (e.g. mutation and drift need to be at equilibrium). However, artificially dispersed species (i.e. non-indigenous, naturalised and invasive species) often do not comply with these assumptions. Thus, the use of phylogeographic approaches to study these species may lead to erroneous interpretations. Considering that self-denominated phylogeographic studies of invasive species have proliferated in recent years and that genomic tools are now more accessible than ever before, kick starting this debate is particularly timely. We argue herein that invasion scientists must carefully use phylogeographic approaches when studying genomic data obtained from the introduced range. In addition, the assumptions of these phylogeographic approaches need to be explicitly considered when interpreting genomic patterns of invasive species. Finally, we suggest abandoning the use of the term ‘phylogeography’ for describing geographically contextualized genomic data from the introduced range to avoid both terminological and methodological confusion.