Invasive species are non-native species that have been introduced by human intervention, outside their natural range and that has the ability to threaten our native wildlife, cause damage to our environment, economy or human health.

Once introduced, control, management and eradication where possible of invasive species can be very difficult and costly; therefore early detection and reactive measures are desirable.

Most non-native (also known as alien) species do not cause any harm and only a small proportion are considered to be invasive.

Below are detailed definitions from the Convention on Biological Diversity – COP 6 Decision VI/23 ‘Alien species that threaten ecosystems, habitats or species’.

  1. “alien species” refers to a species, subspecies or lower taxon, introduced outside its natural past or present distribution; includes any part, gametes, seeds, eggs, or propagules of such species that might survive and subsequently reproduce
  2. “invasive alien species” means an alien species whose introduction and/or spread threaten biological diversity
  3. “introduction” refers to the movement by human agency, indirect or direct, of an alien species outside of its natural range (past or present). This movement can be either within a country or between countries or areas beyond national jurisdiction
  4. “intentional introduction” refers to the deliberate movement and/or release by humans of an alien species outside its natural range
  5. “unintentional introduction” refers to all other introductions which are not intentional
  6. “establishment” refers to the process of an alien species in a new habitat successfully producing viable offspring with the likelihood of continued survival.

For a searchable database of definitions please visit the Convention on Biological Diversity (CBD) Glossary of Terms web page: