jueves, 6 de agosto de 2015

Giant Tortoises Island Hop Across the Galápagos

Credit Galapagos Conservancy
Giant Galápagos tortoises, the world’s biggest, have had it rough. Thanks to pirates and whalers eating them and to non-native species like goats destroying their habitat, four of the 14 documented species are extinct. Most recently, the Pinta species vanished with the 2012 death of Lonesome George, after decades of attempts to get him to reproduce.

But the tortoises emerging from the crates above represent a milestone in tortoise restoration efforts. They are among 201 tortoises recently released onto Santa Fe Island, which lost its tortoise species a century and a half ago.

We wanted to do this for a long time,” said Linda Cayot, the science adviser for the Galápagos Conservancy, which, in collaboration with the Galapagos National Park Directorate, runs the Giant Tortoise Restoration Initiative. It wasn’t easy. Without any Santa Fe tortoises left (nobody alive now has actually seen them – their existence is known mainly from whalers’ logbooks and museum-preserved bone fragments), conservationists turned to a close genetic relative: tortoises from Española Island.

Española is itself a tortoise success story. By the 1960s, the island was so sparsely populated that its 12 females and two males never even crossed paths to mate. Brought to a breeding center on another island, they were joined by a male from the San Diego Zoo, who some naturalists nicknamed “Diego” and who “became the major stud,” Dr. Cayot said. The other two males stepped up too.

The tortoise eggs were incubated, at temperatures adjusted to hatch two females for every male (slightly warmer eggs produce females). At about age 4, able to withstand predators, babies were placed on Española, which now has about 1,000 tortoises, Dr. Cayot said. Santa Fe was next.
Before dawn on June 27, 201 Española tortoises between 4 and 10 years old were ferried there and carried, up to 12 in a backpack, on a long rocky trail to Santa Fe’s interior. The 30 oldest, including two pictured above, have radio transmitters glued to their carapaces.

Periodically, conservationists will find those tortoises to study their movement and effects on vegetation, Dr. Cayot said, noting that about half of repatriated tortoises die because of scarcity of food and water. Those who find what they need are likely to live a century or more.

By The New York Times 
August 6, 2015

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