Arctic foxes brought for fur transformed Alaska’s grasslands into tundra

The foxes reduced seabird populations, which meant less nutrient-rich guano reached the islands. Arctic foxes introduced to more than 400 Alaskan islands for fur changed far more than the local wildlife. According to a study published in journal Science, by preying on seabirds, they disrupted the flow of nutrients from the ocean to land and helped turn some of the Aleutian Islands from grasslands into maritime tundra.The foxes were introduced after the maritime fur trade collapsed in the late 19th and early 20th centuries. They were brought to the islands as an additional source of fur. But while foxes spread across many islands, some remained fox-free because introductions failed or were never attempted.The study compared 18 islands in the Aleutian archipelago, nine with foxes and nine without them. Researchers examined seabird numbers, soil nutrients and plant communities to understand how the introduction of the predators had affected the wider ecosystem.Seabird population disruptedThe biggest change was in seabird numbers. Breeding seabird densities were almost 100 times higher on fox-free islands than on islands with foxes. Researchers estimated that annual seabird guano input...