An invasive alien species is a living organism (animal or plant) that has been introduced by humans, either intentionally or unintentionally, outside its natural environment. It is called "invasive" as it adapts to its new environment while causing significant damage to the biodiversity or the ecosystem services that it provides.

A growing threat 

Alien species have long been introduced in Europe, but not all are invasive and their introduction does not threaten European diversity.

However, due to the considerable increase in trade and strong demand for exotic animals and plants, the threat to the environment is increasing. These species can sometimes cause health problems for humans or domestic or wild animals.

A global issue

The problem of invasive alien species is global. It is also considered to be the second leading cause of biodiversity loss worldwide after the loss of natural habitats (e.g. due to the conversion of these habitats into agricultural areas, industrial areas or areas for human habitation). 

Economic loss

IAS can also cause significant economic damage which is estimated at €12.5 billion per year for the European Union. Direct economic losses affect certain sectors such as agriculture, aquaculture, fishing or forestry, through, for example, the introduction of diseases.

Their control and elimination may also result in significant costs that must be borne collectively by society through the budgets of the public authorities.