A new study published today in the journal PLOS ONE reports that giant tortoises on the island now number about 1,000 self-sustaining creatures, after nearly disappearing in the 1960s, when just 15 were counted.
"The population is secure," said James P. Gibbs, professor of vertebrate conservation biology at the SUNY College of Environmental Science and Forestry and lead author of the paper, in a press release. "It's a rare example of how biologists and managers can collaborate to recover a species from the brink of extinction."
Captive-bred tortoises were originally reintroduced to the island about 40 years ago by the Galapagos National Park Service. The study reports that about half of the tortoises released there since 1975 were still alive as of 2007, and that the tortoises' risk for extinction in the future was low, "with or without continued repatriation."
Gibbs and his team gauged the current population on the island by poring over 40 years of data about tortoises that had been monitored, marked and recaptured on a regular basis for measuring.
While Gibbs called it "a true story of success and hope in conservation," the scientist said there is another hurdle yet to be cleared, if the tortoises are to continue growing their numbers -- recovery of the landscape.
"Population restoration is one thing but ecological restoration is going to take a lot longer," he said. In the late 19th century, feral goats brought to the island ravaged the vegetation. Even after their removal from the island, today resources are more scarce, as small trees and shrubs have taken root whose numbers crowd out the growth of cactus, a key component of the tortoises' diet.
"This is a miraculous conservation success accomplished by the Galapagos National Park Service," said Gibbs, "but there is yet more work to fully recover the ecosystem upon which the tortoises and other rare species depend."
From Discovery News
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