Coexistence theory as a tool to understand biological invasions in species interaction networks: Implications for the study of novel ecosystems

Abstract Questions related to understanding which characteristics of the recipient communities make them vulnerable to invasion (i.e. invasibility) are commonly formulated in such a way that they consider ecological communities as whole entities. Yet, species within recipient communities have specific responses to the introduction of exotic species. As a consequence, little is known about the role of species interaction networks within and between trophic levels in determining the invasion likelihood of exotics introduced in previously uninvaded communities and the temporal dynamics of invaded communities. To obtain a mature understanding of invasion processes and their impacts, I propose here to apply a structural stability approach of species coexistence to the field of biological invasions. The main aim here is to distinguish how direct and indirect species’ responses to invasion in competitive and trophic networks translate to the mechanisms determining the maintenance and stability of species diversity in multispecies and multitrophic assemblages. This approach brings the further opportunity to integrate the field of biological invasions within a broader perspective about the study of novel ecosystems, that is, ecosystems that contain exotic species and face new introductions sometimes under abrupt environmental changes. Moreover, it can help to target specific mechanisms separating winners from losers in novel ecosystems. Synthesis . A solid framework to predict biological invasions and understand community assembly along temporal scales under novel ecosystems can be obtained by framing species’ responses to invasion within recent theoretical and methodological advances stemming from coexistence theory, which seeks to determine how diversity is maintained. A plain language summary is available for this article.