3.3 Invasive alien species
Alien species represent a major threat to ecosystems and this is particularly significant for oceanic island groups. The tortoises that gave the Galápagos islands their name are now threatened by alien introductions. Goats have been a particular problem, but slowly the populations have been brought under control. The habitat, the wariness of goats and remoteness of the islands make eradicating goats a very expensive proposition.
Like the animals on the Galápagos, much of the flora of the islands is also vulnerable to the impacts of introduced alien species. Up to 2017, 821 terrestrial plants had been introduced. Among the most devastating has been the red quinine tree.