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Invasive Species Management


What is an invasive species?
Plants, animals, or other organisms become invasive:

(1) when they are transported (primarily by human actions) into a new ecosystem,
(2) where they are non-native (alien),
(3) and cause or are likely to cause economic or environmental harm or harm to human health.

What species have invaded the Alaska Maritime Refuge?
Arctic and red foxes
Norway rats, black rats, house and deer mice
Arctic ground squirrels
Hoofed animals (reindeer, caribou, cattle, sheep, horses)
Others (voles, hares, hoary marmots, plants)

 

What damage have these alien animals caused on the refuge? 

  • Pushed the Aleutian cackling goose to the brink of extinction 
  • Left some islands barren of the seabirds, ducks, and land birds that used to nest there, threatening the existence of some species that nest only on the refuge 
  • Changed the native plant communities and caused severe soil erosion that in turn affects the breeding success of native wildlife 
  • Brought health hazards from rodent-carried diseases 

Why are islands more at risk from invasive species? 

  • Limited number of native species of plants and animals - what can swim, float or fly to the island 
  • Often unique species or subspecies - different from mainland cousins 
  • No developed "immunity" or adaptations to alien predators 
  • Leading cause of extinctions in island ecosystems worldwide 

What can be done? 

  1. Prevention  
  2. Removal  
  3. Restoration of native animals  

What is being done about invasive species on the refuge?

(1) Prevention (Quarantine) 

  • Island Protection (Pribilofs): The tribal government and residents of the islands have joined the refuge in efforts to keep rats off their islands. The Pribilofs are sometimes called the Galapagos of the North because they shelter some of the largest seabird and fur seal colonies in the world. 
  • Shipwreck Response: When ships go aground, rats flee just as the proverb claims. The refuge staff goes to the site in sensitive areas to prevent "rat spills" just as others try to prevent oil spills. A rat invasion can be much more deadly and long-lasting. 
  • Rat Prevention Tips and Kits for vessels: Learn more. 
  • WWW.stoprats.com - Your source of information on halting the spread of rats in Alaska.  

(2) Removal 

  • First Foxes: Introduced foxes were the most widespread invasive mammal on the Alaska Maritime Refuge and the first targeted for eradication. Beginning in 1949, the refuge has removed foxes from over 40 islands reclaiming more than a million acres of habitat. The long-endangered Aleutian cackling goose recovered from fox predation and was removed from the Endangered Species List in 2001. Populations are rebounding of nesting seabirds and other native birds on fox-free islands. 
  • Hoofed Animals: Reindeer and cattle have been removed from four refuge islands. Hoofed animals remain on one refuge island and 9 other islands that contain both private and refuge lands. 
  • Rats: A Norway rat eradication on 6,861 acre Rat Island in the Aleutians took place in the fall of 2008. No rats were found on the island in the summer of 2009 but another summer of field work is necessary before we can determine if all rats were eliminated. All ground and burrow nesting birds are expected to benefit. Read more... 
  • European Rabbits and Introduced Marmots: Based on an Environmental Assessment and public review completed in the winter of 2010, the refuge plans on removing European rabbits from Poa Island in the Aleutian Islands and introduced hoary marmots from Sud Island in the Barren Island group beginning in the spring of 2010. Both animals compete with native seabirds for burrows, disturb nesting seabirds causing nest abandonment and alter native plant communities. Read more ... 

3) Restoration of Native Wildlife 

  • Aleutian cackling goose: After almost 40 years of effort* the refuge and the nation celebrated the removal of the goose from the Endangered Species List in 2001 - one of the few species to fully recover. (*Work included fox removals, hunting closures where the goose winters, captive breeding of the geese and moving wild geese to islands freed of foxes.) 
  • Seabirds are now returning to those fox-free islands. 
  • Endemic land birds: The refuge is beginning a program to restore the rare Evermann's rock ptarmigan, once native to many western Aleutian Islands but found now only on Attu. Learn more 
  • Kiska Island auklets: Rats are attacking these birds. The refuge is studying what is happening and what can be done to help.   

Learn more

Restoring Alaska's Islands Fact Sheet (pdf)
Refuge invasive species programs
Historic background
Environmental Assessment for Restoring Wildlife Habitat on Rat Island (pdf)
Invasive Species Eradication for Habitat Restoration on Tangik, Poa and Sud Islands

Related LINKS

WWW.StopRats.com (map of where the rats are in Alaska, comprehensive discussion of impacts on wildlife, how to protect your boat and town, on-line ordering of rat kits - a product of the Stop Rats Outreach Team - more than a dozen organizations working to halt the spread of rats in Alaska)

Gateway to Federal and State Invasive species activities and programs (impacts, species profiles, geographic information, news and events, laws and regulations)

Wildlife and People at Risk: A Plan to Keep Rats Out of Alaska, ADF&G

Invasive Species Specialist Group - The World Conservation Union (focus on biodiversity loss, especially threats to oceanic islands)

Cooperative Initiative on Island Invasive Alien Species - The World Conservation Union

National Biological Information Infrastructure - U.S. Geological Survey (current biological issues, geographic perspectives, teacher resources)

Invasive Species: Alaska (16 page pdf ) (Union of Concerned Scientists)

Last Updated: May 27, 2014
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