QUITO (AFP) - Tourism, overpopulation and non-native species are threatening the ecosystem of the Galapagos Islands, the archipelago which inspired British naturalist Charles Darwin's theory of evolution, experts say.

In order to protect the UNESCO World Heritage site, Correa this week issued orders to restrict tourist traffic, overhead flights and residence permits on the isles 1,000 kilometers (621 miles) from Ecuador's coast.

The 8,000 square kilometer (3,088 square mile) islands and 45,000 square kilometers (17,374 square miles) of surrounding waters are populated by giant turtles, sharks, Darwin finches, marine iguanas, sea lions, rare trees and insects.

A major factor in the ecosystem's decline has been the introduction of dogs, cats, goats and donkeys -- species that were not on the island before.