Despite international environmental agreements and conservation efforts worldwide, we are facing the sixth great extinction, with up to 1 million species currently at risk. Invasive Alien Species (IAS)  –  species whose introduction and spread outside their natural past or present distribution threatens biological diversity – are one of the biggest causes of biodiversity loss and species extinctions. They have been partially or fully responsible for at least 46% of all known bird extinctions and 86% of all recorded extinctions on islands.

Fairy Tern in Palmyra Atoll. Photograph: Andrew Wright for Island Conservation