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.org - Your source of information on halting the spread of rats in Alaska.
(2) Removal
- First Foxes: Foxes were the most widespread invasive mammal on the Alaska
Maritime Refuge and the first targeted for eradication.
- Success: The long-endangered
Aleutian cackling goose recovered and was removed from the Endangered Species
List in 2001. Populations are rebounding of nesting seabirds and other native
birds are also rebounding 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.
- Now Rats: An Environmental Assessment has recently been released evaluating a proposal to restore 6,861 acre Rat Island in the Aleutians by removing all rats. This will be the first rat eradication in the refuge. All ground and burrow nesting birds are expected to benefit. Comments will be accepted on the plan through January 11, 2008. 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
Related LINKS
WWW.StopRats.org (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)
