Island species are under threat. Despite only making up about 3% of the Earth’s land area, islands are home to about 20% of all species and 50% of endangered species.
Approximately 80% of all known extinctions have occurred on islands. One of the primary causes for extinction of island species is the presence of invasive species. Since 1994, the charitable organisation Island Conservation has fought to prevent these extinctions by removing invasive species from island ecosystems. Focusing on islands where the need is greatest, as biodiversity is concentrated and the rate of extinction is high, Island Conservation has deployed team members to 52 islands worldwide to protect 994 populations of 338 native species.
Once invasive species are removed, island ecosystems can often recover with little or no extra intervention. After the removal of invasive rats from Hawadax Island (formerly known as Rat Island), Alaska, bird species on the island increased dramatically and for the first time ever, breeding tufted puffins were documented on the island.
Working together with local communities, government management agencies and conservation organisations, Island Conservation enables many species to be brought back from the brink of extinction.
One such success story is the Anacapa Island Restoration Project. Invasive black rats on Anacapa Island, part of the Channel Islands Archipelago in California, were decimating native species populations, particularly the threatened Xantus’s murrelet (now renamed Scripps’s Murrelet),and the endemic Anacapa deer mouse. In 2001 and 2002, Island Conservation and partners removed invasive rats from Anacapa Island. Since the removal of the rats, the nesting success of Xantus’s murrelet has increased by 90% and the Anacapa deer mice are thriving. In 2013, scientists documented the endangered ashy storm-petrel breeding on the island for the first time in history.
The removal of invasive species from island habitats has also led to the rediscovery of species once thought to be extinct. In 2011, Island Conservation and their partners removed invasive rats from Rábida Island, Galapagos to protect the native species. A return visit to the island two years later led to an unexpected discovery of a gecko species, known only from subfossil records, which was thought to be extinct.
To date, Island Conservation have recovered and protected 338 seabird nesting colonies and taken action to restore 52 islands from the most damaging invasive animals. With their continued work and the launch of Small Islands, Big Difference – a campaign which aims to save our world’s most vulnerable species by removing invasive species from islands at an accelerated rate, many more island species can be rescued from extinction.
Over the next few weeks we will be sharing with you more about the great work that Island Conservation have carried out.
Discover ARKive’s favourite island species from around the world.