Threats to species

Alien species

Alien species (i.e. introduced from one ecosystem to another) are also referred to as 'invasive species', 'exotic species', 'gene pollution', 'marine pests' or 'marine invaders', when they are a threat to the biodiversity of an ecosystem. They can also have a negative effect on human and animal health and production in agriculture and fisheries.

There are many examples of the direct detrimental and often irreversible effects of alien species on terrestrial, freshwater and marine ecosystems around the world. This complicates conservation efforts and sustainable use of biological diversity. Alien species are introduced to new areas by human activities, e.g. deliberate introductions of exotic species for mariculture, unintentional introductions associated with the importation of mariculture species, ship fouling (and boring), dry and semi-dry ballast, and ballast water. Scientists recognize that assessing the impact of known marine pests require a multi-disciplinary approach involving areas as diverse as economics, engineering, environmental impact assessment, eco-physiology and taxonomy.