Invasive Species

photo of a gypsy moth on a tree
Gypsy moth larvae can be carried by wind as well as attach to unsuspecting people, vehicles, and other objects. During outbreaks, larval feeding may completely defoliate host trees and cause the host trees to die.

What are Invasive Species?

An invasive species can be an animal, a plant, an insect, or any other living thing that is:

  • not native to an area
  • able to pervade a region because of insufficient checks (such as natural predators or diseases).

Invasive species can be found in all kinds of areas, including forests, waterways, and urban environments.

Why Are Invasive Species Bad?

They can take over a habitat, crowding out important local species that other plants and animals depend upon.

Invasives change what can grow and thrive in an area, which affects the whole food chain. They affect how many and what kind of fish are available to eat for both us and other animals.

They affect how we experience nature (e.g. it's hard to canoe or kayak in overgrown waterways covered in plants that aren't supposed to be there).

Some examples of damage invasives can (and have) caused include:

  • killing wildlife,
  • damaging boats and gear,
  • clogging water pipes and hydropower facilities, and
  • chewing wiring.

How are Invasive Species Introduced?

Most invasive species are introduced to a new region through human activity. Some are intentional actions, such as:

  • agricultural crops,
  • landscaping and ornamental plants,
  • released or abandoned pets, and
  • bait fish.

Others arrive through unsuspecting human carriers.

  • They hitchhike on visitors’ clothes, shoes, gear, or transport.
  • Boaters move invasive species that have attached to their equipment or clothing to new bodies of water.
  • Hikers and hunters move invasive species around through mud on boots and other equipment.
  • Drivers move invasive species that catch in their wheel wells, tires, or grills.
image of a caught fish being put back in the water with a slash through it
If you catch an invasive species in the water, don't put it back!

Several Invasive Species in Alaska

  • Atlantic Salmon - these could compete with native salmon and trout for spawning and rearing habitat. Because Atlantic salmon are held in large, overpopulated net pens, they are treated for disease and parasites. Treated fish may not show signs of pathogens but can be carriers. ADF&G is concerned that Atlantic salmon that can escape or are released from aquaculture net pens may introduce disease or parasites to valuable Pacific salmon fisheries.
  • Northern Pike (in southcentral Alaska) - Illegal stocking of northern pike is reducing the quality of fishing in Southcentral Alaska and threatening both wild and stocked fisheries. The northern pike is native to most of Alaska, but it does not naturally occur south and east of the Alaska Mountain Range except for a small, remnant population near Yakutat.
  • Norway Rat - Because rats have a wide diet, they can prey on a lot of Alaskan wildlife (for example, bird eggs). They also carry parasites, pathogens and diseases that can be harmful to other species as well as humans.
  • Rock Dove - These can be crop pests. Because they live in large numbers, they can displace native birds in developed areas. But the largest concern is that rock doves carry a variety of parasites and pathogens that could suppress the health of native birds in Alaska.

If you see any of these (or other) invasive species, please report them immediately.

What Can You Do to Prevent the Spread of Invasive Species?

There are many different, easy things you can do help protect from invasives. Whether you're an avid outdoor person or you just like to take the occasional stroll, each time you go outside you have the opportunity to make a difference.

  1. Clean Your Gear- When moving between different states, regions, or even countries, make sure to clean your shoes, waders, boats, trailers, off-road vehicles, and other gear that you have used outside. Not only does it help prevent the introduction of invasive species but also extends the life of your gear. Allow wet gear to dry completely before re-using it somewhere else.
  2. Empty Out Your Water - Empty all water from coolers, bilge pumps, buckets, and wring out gear before leaving the boat launch or fishing areas.
  3. Obey the Laws - Laws are in place to protect people and the surrounding environment.
  4. Check with the appropriate agencies for local laws, and
  5. declare all plants and animals at appropriate customs checks.
  6. Check out ADF&G's Invasive Species Legal Requirements page for information about regulations.
  7. Check your Pets - If you are considering bringing a pet to Alaska or buying one online, make sure the animal is on the Clean List of Animals. Avoid ordering exotic pets off the internet or purchasing from websites such as Craigslist.
  8. Oh Rats! - Never release live rats into the wild, and never throw captured rats overboard. They are excellent swimmers and may reach land.
  9. Use Local Products - Using local products can help reduce the spread of invasive that like to hitch a ride. Remember, just because you don't see it doesn't mean it's not there!
  10. Purchase fruits and vegetables from the immediate region.
  11. Firewood should only be used within a 50 mile radius of its source.
  12. Learn the Local Species - Knowing what is supposed to be there helps identify that which does not belong.
  13. Report immediately - If you see a plant or animal that you know isn't native to that area, take a picture of it and report where you found it (using GPS coordinates if you can) to help officials respond quicker to the threat.

    Email reports of invasives to the Alaska Department of Fish and Game, Invasive Species Program or phone the Invasive Species Hotline at 1-877-INVASIV (1-877-468-2748).

Dalton Discoveries: Uninvited Guests

Note: This Embedded video resides on the official Alaska Public Lands Information Center YouTube channel

Published on Apr 25, 2014

In 2004 the BLM discovered white sweet clover, an invasive species, was pushing out native plant life along the Dalton Highway. While non-native plants are often found along highway corridors throughout Alaska, this plant has also made its way along some of the waterways that branch off from the highway.