The Galapagos Islands, a remote archipelago off Ecuador’s coast, are renowned for their unique biodiversity, which inspired Charles Darwin’s theory of evolution. Its isolation allowed species to evolve without many natural predators or competitors. However, human arrivals introduced new challenges, including the establishment of goats as an invasive species. Brought by fishermen in the early 20th century as a food source, these animals thrived in the absence of natural controls.
Impact on the Ecosystem
The rapid population growth of feral goats had a significant impact on the Galapagos ecosystem. Goats multiplied, reaching an estimated 100,000 individuals on Isabela Island by 1997. Their grazing habits stripped native vegetation, including endemic plants like Scalesia and Opuntia cacti, pushing them close to extinction. This led to significant habitat degradation and soil erosion.
The goats competed with native herbivores, such as giant tortoises and land iguanas, for dwindling food resources. This competition reduced the tortoises’ food supply, causing populations to decline and, on some islands like Pinta and Santiago, nearly wiping them out. The goats also disrupted island ecosystems that had evolved without large grazing mammals, further threatening unique species like finches and mockingbirds.
The Eradication Effort
Recognizing the threat, Project Isabela was launched between 1997 and 2006. This environmental restoration project aimed to eliminate large introduced mammals, primarily goats, from northern Isabela, Santiago, and Pinta islands. The project was a large-scale international collaboration, utilizing advanced technology and scientific strategies.
Innovative techniques were employed to achieve eradication. Aerial hunting from helicopters by skilled sharpshooters rapidly reduced goat numbers in high-density areas. Ground hunting teams, assisted by specially trained dogs, then targeted remaining populations. The “Judas goat” method, using sterilized, radio-collared goats to lead hunters to hidden herds, located the last elusive animals. This effort led to the eradication of approximately 140,000 goats from over 500,000 hectares, including the use of approximately 770 Judas goats on Isabela and over 200 on Santiago.
Recovery and Future Conservation
Following the successful eradication of goats, the Galapagos ecosystem began to show signs of recovery. Native plant species, including highland shrubs, forest tree seedlings, and Opuntia cacti, started to regenerate, with some species previously confined to protected areas now expanding. This vegetation recovery benefited native animal populations. The endangered Galapagos rail, for instance, made a comeback on multiple islands, including Floreana, where it had not been documented since the late 1980s.
Giant tortoise populations also rebounded, reclaiming their natural habitats as food sources became abundant again. The success of Project Isabela offers lessons for invasive species management globally. It demonstrated that even large-scale eradications are achievable with sufficient resources, scientific planning, and dedicated effort. The project underscores the importance of proactive, long-term conservation strategies to protect island ecosystems from the ongoing threat of introduced species.