Feral animals cause ecological shifts on isolated islands

Scientific studies have highlighted the ecological consequences of introducing domestic animals to isolated islands. On Amsterdam Island, a French territory in the southern Indian Ocean, five cattle were introduced in 1871. Over the following century, the population grew to approximately 2,000 head through natural selection and feralization, providing researchers with unique DNA data on how domestic species adapt to the wild.

Similarly, on Great Island (Manawatāwhi) in the Three Kings group of New Zealand, four goats were released in 1889 to serve as a potential food source for shipwrecked sailors. The population expanded rapidly due to an abundance of food and a lack of predators, leading to significant environmental degradation. The goats consumed native vegetation, contributing to the loss of nearly one-third of indigenous forest bird species and threatening various plant populations. By 1946, the goat population was eliminated through culling.