Plant invasions: merging the concepts of species invasiveness and community invasibility

TLDR

Plant invasion ecology has advanced since 1990, with key concepts such as species invasiveness, community invasibility, and the naturalization‑invasion continuum shaping current understanding of how vascular plants colonize natural and semi‑natural ecosystems. The study seeks to answer three core questions from the SCOPE programme: which species invade, which habitats are invaded, and how invasions can be managed. This review synthesizes evidence on vascular plant invasions in natural and semi‑natural ecosystems, focusing on fundamental ecological issues of species invasiveness and community invasibility. Emerging research tools and interdisciplinary links with succession ecology, community ecology, conservation biology, and weed science have reinforced the conceptual foundations of invasion ecology.

Abstract

This paper considers key issues in plant invasion ecology, where findings published since 1990 have significantly improved our understanding of many aspects of invasions. The review focuses on vascular plants invading natural and semi-natural ecosystems, and on fundamental ecological issues relating to species invasiveness and community invasibility. Three big questions addressed by the SCOPE programme in the 1980s (which species invade; which habitats are invaded; and how can we manage invasions?) still underpin most work in invasion ecology. Some organizing and unifying themes in the field are organism-focused and relate to species invasiveness (the tens rule; the concept of residence time; taxonomic patterns and Darwin’s naturalization hypothesis; issues of phenotypic plasticity and rapid evolutionary change, including evolution of increased competitive ability hypothesis; the role of long-distance dispersal). Others are ecosystem-centred and deal with determinants of the invasibility of communities, habitats and regions (levels of invasion, invasibility and propagule pressure; the biotic resistance hypothesis and the links between diversity and invasibility; synergisms, mutualisms, and invasional meltdown). Some theories have taken an overarching approach to plant invasions by integrating the concepts of species invasiveness and community invasibility (a theory of seed plant invasiveness; fluctuating resources theory of invasibility). Concepts, hypotheses and theories reviewed here can be linked to the naturalization-invasion continuum concept, which relates invasion processes with a sequence of environmental and biotic barriers that an introduced species must negotiate to become casual, naturalized and invasive. New research tools and improved research links between invasion ecology and succession ecology, community ecology, conservation biology and weed science, respectively, have strengthened the conceptual pillars of invasion ecology.