Introduced Arctic foxes turned Alaskan Aleutian grasslands into nutrient-poor tundra
A new study shows that Arctic foxes brought to the Aleutian Islands for fur have drastically reduced seabird colonies, cutting marine-derived nutrients and converting grasslands into maritime tundra.
A recent paper in Science documents how Arctic foxes, introduced to over 400 Aleutian islands after the maritime fur trade collapsed, have altered the archipelago’s ecology. On islands with foxes, seabird breeding numbers are almost a hundredfold lower than on fox-free islands, reducing annual guano input from a median of 361.9 g/m² to just 5.7 g/m². This drop in marine-derived nutrients leads to soil phosphorus levels more than three times higher on fox-free islands and supports abundant grass biomass, whereas fox-infested islands host a mix of grasses, shrubs and forbs.
A three-year fertilisation experiment on a fox-occupied island produced a 24-fold increase in grass growth, mirroring conditions on predator-free sites. The study concludes that fox-driven seabird declines have transformed parts of the Aleutians from lush grasslands into maritime tundra, prompting restoration efforts that include fox removal by the US Fish and Wildlife Service.
Why it matters
It reveals how an introduced predator can cascade through ecosystems, affecting soil health and vegetation on a regional scale.
In this story
