They usually have the ability to grow or reproduce quickly, causing harm to native wildlife and habitats. There are many invasive species around the world, introduced both deliberately and accidentally.

Invasive species are a particular worry for the conservation of islands like Galapagos. Islands have high levels of endemism – species that don’t exist anywhere else – and populations are often small, making them especially vulnerable to extinction. The isolation of the Galapagos Islands has prevented the arrival of new species over time, which means that native species here have few strong competitors or predators.

Invasive species in the Galapagos Islands

Since the Islands were first discovered in 1535, many species have been introduced by humans, mostly before we knew the impacts these species would have on the natural ecosystem. Some were deliberately brought to the Islands for agricultural and aesthetic purposes. Pigs, goats and chickens were brought to provide food, species such as domestic cats and dogs were brought for companionship, and many ornamental plants were introduced to create gardens. Other species were introduced unintentionally, including rats and various insects and pathogens. Today we believe there are more than 1,500 introduced species in the Galapagos Islands.

Controlling invasive species

Various measures are in place across Galapagos to control, eradicate and keep out invasive species. These range from scanning every visitor’s bag on arrival and departure, to capturing and removing invasive mammals and plants.

GCT is supporting the Galapagos National Park Directorate in their mission to control invasive species. One of the invasive species posing the biggest threat to Galapagos wildlife is the parasitic avian vampire fly, Philornis downsi. The larvae of this fly feed on the eggs and hatchlings of many species of Galapagos landbird. This means chicks are more likely to die in the nest, and has led to a decline in the population of many species of Darwin’s finch. Over the last few years, an international research network led by the Charles Darwin Foundation has significantly improved our understanding of this fly, in order to produce an effective plan to control its spread and minimise the impact on Galapagos landbirds.

We are also long-term supporters of the efforts to restore Floreana island, which involves the most ambitious eradication programme ever carried out on an inhabited tropical island. The removal of invasive rats and feral cats from the island will allow the reintroduction of 12 locally extinct species, including iconic landbirds such as the little vermilion flycatcher and the Floreana mockingbird.