Invasive introduced species: challenging the ecological paradigms

Abstract

As a result of strong human pressure on aquatic and semiaquatic ecosystems, new species introduced from several parts of the World are increasingly observed. Some of these species become invasive and can threaten biodiversity and ecosystem functioning. This paper is an attempt to disentangle scientific facts or theories from conventional wisdom based on subjective perception or cultural clichés that present invasive introduced species in an essentially negative light Especially, we point out that in the face of a real threat for biodiversity and ecosystem functioning, invasive species may have positive effects or uses. Several issues in invasion management are examined. While characteristics of invasive species cannot easily be predicted, many invasions take place in previously modified ecosystems. Furthermore, invader eradication is not always the best answer for targeting self-sustainable healthy ecosystems. Since exotic species will irrevocably increase in proportion within our ecological communities in the near future, one might as well be ready to adapt to this novel biodiversity by accepting or managing the presence of some invaders.