22 Apr '11, 4am
Substitute Tortoises Help Repair an Island Ecosystem
For thousands of years, on the small island of Ile aux Aigretts in the Indian Ocean, ebony trees and giant tortoises shared a symbiotic relationship. The trees provided food for the tortoises, who, in turn, distributed their tough seeds throughout the island, allowing them to flourish. With the arrival of settlers, however, the tortoises were made extinct and the trees were all but cleared entirely. But now, in an effort to regrow the endangered ebony forests, conservationists have introduced an exotic tortoise to serve as a substitute, a process known as 'rewilding' -- and for the first time ever, there's empirical evidence that it can save an ecosystem.