Invasive ‘alien’ species may compete with already existing local biodiversity and domestic animals, introduce infectious transboundary diseases (often emerging), and have a detrimental effect on the environment. Invasive animal species may belong to any species, including molluscs, arthropods, fishes, amphibians, reptiles, birds or mammals. Moreover, invasive plants can have an impact on the animal kingdom.
Natural ‘alien’ species invasions, notably through migrations, have always occurred, and there have also been accidental or intentional introductions by man, often with serious consequences. Livestock and companion animals have always accompanied man during his own historical migrations.
After a definition of what can be considered an invasive species, these issues of the Review intend to give an overview of all aspects of animal invasions and their mechanisms, largely based upon historical records of known animal invasions; they will also describe the impacts, both negative and positive, of the invasions and look to the future. Finally, these Reviews will consider how to prevent the introduction of invasive ‘alien’ species and how to control or mitigate their effects.