SANTIAGO ISLAND

Of the uninhabited islands, Santiago’s history of introductions and exploitation of natural resources is most similar to the inhabited islands. This is, in part, because of the companies mining salt there in the 1920s and the attempt at colonization in the 1930s. However, it began long before that with the exploitation of giant tortoises and the introduction of goats, pigs, donkeys, rats, and mice. Introduced plants, some arriving with the colonization attempts, have also spread throughout the island. By the establishment of the Galápagos National Park in 1959, the giant tortoise population of Santiago had been reduced to some 500 animals, with a predominance of males. Nesting was generally unsuccessful due to predation by pigs. The Santiago tortoises were soon included in the tortoise rearing and repatriation program; rock walls were also built around their natural nests to protect them from pigs.

Over decades goats destroyed the natural woodlands, creating grasslands across the higher elevations of the island. Pigs systematically destroyed nests of many of the native species, including giant tortoises, sea turtles, and Galápagos petrels, among others. Attempts at goat and pig control were carried out by the Galápagos National Park beginning in the 1980s. However, it was not until more modern eradication technologies were applied as part of Project Isabela that complete eradication of goats, pigs, and donkeys was achieved. The island was declared pig-free in 2000, and goat- and donkey-free in 2006. The restoration of the vegetation is rapidly occurring, although there is now a problem with some of the introduced plant species that had been held in check by the goats.

Galápagos rails have also made a comeback in the highlands and nesting of native species is more successful. For decades it was believed that on all islands with black rats, the endemic rice rat had gone extinct. However, a remnant population of rice rats was discovered on Santiago in 1997. The challenge today is to ensure that this population continues to survive in spite of the presence of black rats.