Goats introduced to Aride Island in the Seychelles in 1870 had to be eradicated roughly 50 years later to prevent an ecological disaster, according to a study on introduced mammals on the islands of the western Indian Ocean. The removal of the goats from Aride, completed before 1920, ranks among the earliest documented cases of an introduced mammal being eliminated from the islands of the region.
The study found that the Aride case was part of a much larger pattern. Researchers documented 74 eradication attempts across 45 islands in the western Indian Ocean, with most of the operations concentrated in the Seychelles, Mauritius and its dependencies, and the Iles Eparses.
How goats altered island vegetation
Goats were among the introduced animals that most worried conservationists because of their ability to reshape vegetation through grazing. On small islands, where ecosystems occupy limited space and are cut off from the mainland, that grazing pressure could hit native plants especially hard.
Aride Island became one of the first places where removing an introduced animal was treated as a necessary step to protect the ecosystem. Records gathered by the researchers show the goats on Aride were eliminated by shooting before 1920.
The episode became significant in the history of island conservation because it showed that protecting nature does not always mean preserving every species present. In some cases, it can also mean removing species that people brought in and that were never part of the original ecosystem.
The problem repeated on other islands
Aride was not an isolated case. The study records later attempts to eliminate feral goats from other Seychelles islands. In total, the researchers documented goat eradication efforts on five islands, some covering as much as 11,115 hectares.
The task grew harder once the animals managed to establish themselves and survive without depending directly on people. Cutting their numbers did not guarantee they would disappear, since a handful of surviving goats could still reproduce and rebuild the population.
Because of this, later programmes needed more organised searches and constant follow-up monitoring. The researchers also drew a distinction between a population that was deliberately eradicated and one that vanished after control measures were applied without a full eradication effort.
Eradication becomes a conservation strategy
The goat removals were part of a wider expansion of programmes to clear introduced mammals from the islands of the western Indian Ocean. The study notes that three quarters of the 74 documented attempts took place after the year 2000.
Altogether, the operations targeted nine mammal species, including goats, hares, rabbits, cats, rats and mice. Some interventions were carried out on small islands, while others covered territories spanning thousands of hectares.
In the Seychelles, related cases were also recorded on the Aldabra Atoll islands of Polymnie and Ile Esprit, where goats had disappeared by the 1970s following control measures. More ambitious eradication programmes were later developed on other islands of the atoll.
The Aride case shows how an introduced species can linger for decades before becoming a conservation problem. More than a century after that first recorded elimination, it now forms part of a broader strategy to restore island ecosystems affected by species that never originally belonged there.
