Biogeographic effects on early establishment of an invasive alien plant

Abstract

• Premise of the study: Biotic resistance is often studied in the context of how interactions between native biota and invading species influence the success of those invaders. Seldom, however, is the strength of “resistance” compared biogeographically, where the ability of a species to impede invader establishment is contrasted between an invader's native and introduced recipient community.• Methods: We conducted an experiment to examine how community diversity influences seedling recruitment of a plant invader where it is native and contrasted with results previously published from introduced ranges. In Switzerland, we created recipient communities that varied in species and functional richness and invaded them, or not, with seeds of Centaurea stoebe, a native European plant that has been previously used in an identical experiment in North America, where it is a prominent invader.• Key results: The biogeographic comparison revealed that the recipient community largely prevented C. stoebe seedling establishment at home (Switzerland), but not away (Montana, USA), and that diversity of the resident vegetation did not contribute to the effects observed in the introduced range.• Conclusions: Our results provide evidence that differences in the biogeographic conditions and/or overall level of competition of resident community between the native and introduced range considerably suppresses seedling recruitment of the invasive plant, rather than resident diversity itself. In the case of C. stoebe, the surprisingly low establishment success in the experiments conducted in the native compared with the introduced range is likely to be influenced by the higher level of competition with resident community, by abiotic environmental conditions or interactions between these two factors in the native range. Release from factors suppressing seedling recruitment at home may contribute to the successful invasion of C. stoebe in North America.

Ecotypic differentiation and phenotypic plasticity combine to enhance the invasiveness of the most widespread daisy in Chile, Leontodon saxatilis

“…saxatilis had strong phenotypic plasticity and, to a lesser extent, ecotypic differentiation. Leontodon saxatilis biomass was far greater when it grew in its invasive range than when it grew in its native range, which is similar to other alien species 60–63 .…”

Climate change both facilitates and inhibits invasive plant ranges in New England

“…To quantify invasion risk, we focused on establishment, because it is the most important process in determining invasion success (37,38). Focusing on establishment allows rapid risk assessments, which are particularly critical for managing invasions when a species is already known to be an invasion threat elsewhere.…”

The importance of factors controlling species abundance and distribution varies in native and non‐native ranges

“…Despite the knowledge gained from comparing species in native and non-native ranges, at least three issues are hindering progress in this realm of ecological biogeography. First, field experiments assessing factors that Studying species in native and non-native ranges has provided considerable insight into the ecological and evolutionary mechanisms underlying invasions (Maron et al 2004, Firn et al 2011, Parker et al 2013, Sun et al 2015, Taylor et al 2015, expanding our understanding of the processes that control species abundance and distribution (Hierro et al 2005, Callaway and Maron 2006, Sax et al 2007, Capinha et al 2015. For example, field experiments conducted in the native and non-native range of Clidemia hirta have shown that herbivores and fungal pathogens decrease its survival in understory habitats at home, limiting the distribution of the species to open habitats in the native range; however, the absence of enemies abroad apparently allows the species to invade forest understory in the non-native range (DeWalt et al 2004).…”