Posted on behalf of Henry Nicholls.
It is said that you’re never more than 3 metres away from a rat. Until recently, the animal residents of Rábida in the Galapagos might confidently have made this claim. But the island — all 5 square kilometres of it — is now officially rat-free. It is the latest success in the Galapagos National Park’s against-the-odds effort to eradicate invasive rodents from the entire archipelago by 2020 and place Ecuador at the top of the world’s rat-eradication league.
The delivery of rodent bait to Rábida, which sits just to the south of the main island of Santiago, took place in January 2011. Within months, the benefits were already apparent. Researchers turned up snails that nobody had seen since 1906. They also found an impossibly cute reptile — of the genus of leaf-toed geckos called Phyllodactylus — previously known only from partially fossilized remains dated to more than 5,000 years ago, conservationists reveal. “The real measure of the success of the restoration effort will be the recovery of the island’s native species”, says Brad Keitt, director of conservation for Island Conservation, one of the Galapagos National Park’s partner organizations with special expertise in the eradication of invasive mammals from islands.
Rábida may not be the largest island in the Galapagos, but the eradication of an entrenched species from such an inhospitable landscape has been difficult. It has required the use of a helicopter fitted with an industrial-scale hopper to distribute the poison. Workers also had to hold the island’s Galapagos hawks in captivity for the duration of the project, to protect them from dining on poisoned rat.
Over the weekend, the Galapagos National Park and its collaborators completed the next phase of their rat offensive, delivering a second, and hopefully final, poison drop over Pinzón, an island more than three times the size of Rábida at around 18 square kilometres.
It will take time to judge the success of this intervention, which serves as a proof of principle. But in a press release issued at the weekend, the Galapagos National Park announced that in 2014 it will be taking on the rats of 172-square-kilometre Floreana, one of the main islands in Galapagos.
At present, the record for the largest island to be liberated from the scourge of invasive rats probably belongs to New Zealand for its 113-square-kilometre Campbell Island. Australia could inch to the lead with Macquarie Island, where poisoned bait was distributed in 2010 and 2011, says Karl Campbell, senior programme director for Island Conservation. But Floreana would be “the largest island to be eradicated of rodents in the world”, says Campbell.