Jacques Tassin is a researcher in the Environment and Society department of CIRAD, a French research centre working on international agricultural and development issues.

The Nile perch, which is widely available in supermarkets and restaurants, is a typical example of an invasive species. A few years after its introduction into Lake Victoria, all the small local species had disappeared — as had the small-scale, family-run fishing industry. Introducing a few rabbits in Australia resulted in the devastation of millions of acres of land and a major ecological catastrophe. Certain tropical plants have become rampant in the Northern Hemisphere.
Because it is feared, biological invasion is a subject of public concern, one that Jacques Tassin examines dispassionately from a scientific angle. After all, maize and tomatoes — invasive species originally brought to Europe from South America — are no longer regarded as harmful. And where does such a narrow approach come from which sees ‘nature’ as a collection of well-ordered ecosystems that have existed for all eternity? Not only do animal and plant species continue to evolve but global exchanges and climate change have turned biological invasion into a natural phenomenon, even if in most cases it is caused by humans.
The key to the problem would appear to lie in abandoning an idealised, rather romantic and never-changing Nature in favour of one that is under constant renewal, healthily managed and mastered. Not all so-called invasive species are harmful and for everyone’s sake it is important to accompany rather than fight environmental change. The war of the species will not take place.

• Setting aside irrational, emotional reactions, the author looks at invasive species from the scientific angle.
• We must give up a romanticised view of nature and focus on mastering environmental change.