The National Wildlife Federation

Donate Donate

An Alien's Long Reach

A study of the Aleutian Islands shows how the effects of introduced species can spread in unpredictable ways

  • Laura Tangley
  • Aug 01, 2005
WHEN FUR TRADERS introduced foxes onto some Aleutian Islands in the 1700s, the predators quickly wiped out huge colonies of ground-nesting seabirds--and ultimately transformed entire ecosystems.

In a survey of dozens of islands, researchers found that on those colonized by foxes, scrubby tundra has replaced the lush grasslands that still carpet fox-free islands. Based on soil nutrient tests, they conclude that native vegetation relies on fertilization by seabird droppings. The study, published in Science, "shows how the effects of introduced species can spread in unpredictable ways," says lead author Donald Croll, a University of California–Santa Cruz ecologist.

Get Involved

   Please leave this field empty

Where We Work

More than one-third of U.S. fish and wildlife species are at risk of extinction in the coming decades. We're on the ground in seven regions across the country, collaborating with 52 state and territory affiliates to reverse the crisis and ensure wildlife thrive.

Learn More
Regional Centers and Affiliates