Giant Tortoises in the Galapagos are Recovering After Near-Extinction

On the Galapagos island of Española, a population of endangered tortoises once dwindled to just over a dozen. Now, researchers have announced that these tortoises are a true success story and have rebounded 40 years after the first captive-bred tortoises were reintroduced on the island.

"The global population was down to just 15 tortoises by the 1960s," said James P. Gibbs, one of the researchers, in a news release. "Now there are some 1,000 tortoises breeding on their own. The population is secure. It's a rare example of how biologists and managers can collaborate to recover a species from the brink of extinction."

Over the course of 40 years, tortoises were marked, recaptured repeatedly for measurement and monitored by members of the Galapagos National Park Service and visiting scientists. By examining this data, the researchers managed to track the population and understand how it has grown over this time period. Now, it seems as if the tortoise population is stable.

Yet while the population is stable, it's not likely to increase. The island once suffered from an influx of invasive goats, which have now been eradicated. After the goats devoured grassy vegetation and then were removed, more shrubs and small trees began to grow on the island. This, in particular, hinders the growth of cactus, which is a vital part of a tortoise's diet, and the tortoise's movement.

Even so, the fate of these tortoises is looking bright. Their population is stable which means that once the landscape recovers, they're set to repopulate the island.

"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."

The findings are published in the journal PLOS One.