A joint expedition between the Galapagos National Park Service, Yale University and the Galapagos Conservancy, is under way to rescue tortoises of two extremely endangered – presumed extinct – giant species, so they can be bred in captivity and then re-established in the archipelago.
Dr James P Gibbs, a conservation biologist at the SUNY College of Environmental Science and Forestry (ESF) in Syracuse, New York, who is part of the team, said there are thousands of tortoises living on Wolf Volcano on Isabela Island and “amongst them are some rather special ones”.
Dr Gibbs, who has worked with Galapagos tortoises since 1994, credited his colleagues at Yale University with the genetic analysis that revealed in 2012 that some of the tortoises at Wolf Volcano are descendants of the species of tortoises that are extinct on their native islands of Pinta and Floreana. Floreana tortoises have not been seen for more than 100 years – Charles Darwin was one of the last to remark on them. Researchers launched a high-profile search for a mate for the last known living Pinta tortoise, Lonesome George, but the effort was unsuccessful and he died in 2012.
Given the discovery of the population living on the volcano, Dr Gibbs said George actually might not have been the last member of his species.
“We don’t know yet. There may well be some pure Pinta tortoises on Wolf Volcano,” he said. “But there are certainly hybrids. Rescuing as many of these as we can find, breeding them in captivity and releasing their offspring back to their native islands starting in five to 10 years will enable jump-starting the process of evolution, letting natural selection recreate these species once they are back out on their islands.”
The tortoises of the Galapagos serve as ecological engineers, dispersing seeds and browsing as well as shaping the vegetation as they move around the landscape; they can help restore an ecosystem that has been degraded by species such as goats that were introduced to the islands by humans.
Wolf Volcano erupted in May 2015 in a spectacular flow of lava that Dr Gibbs witnessed from a small plane. The tortoises apparently were not threatened by the lava flows.
Scientists speculate that the tortoises are descendants of animals left on Isabela Island by whalers, who collected huge numbers of tortoises for food but also deposited tortoises in various locations so they could serve as backup for subsequent voyagers. Ironically their destructive actions may now hold the key to restoring some species thought to be extinct.
Dr Gibbs spent the last three months before his departure from Syracuse purchasing and packing enough supplies to fill 15 aluminium chests and arranging transfer of the material to Ecuador.
“In principle, it’s very simple; removing tortoises to a captive breeding facility on another island. In practice it involves a helicopter and a ship and a lot of people and a lot of logistics and cost and equipment,” he said.