Invasive species are living organisms including plants, animals, fish, insects, bacteria, etc. that are not native to an ecosystem and cause measurable harm. The harm caused by invasive species can come in the form of environmental harm, economic harm, as well as direct harm to human health. These species oftentimes reproduce quickly and spread aggressively, allowing them to out-compete native species.
Invasive species are widely cited as one of the largest threats to biodiversity worldwide. Additionally, the Kenai Peninsula Fish Habitat Partnership has rated aquatic invasive species as the highest threat to lowland groundwater/wetland dominated systems, closed-basin lakes, and clearwater connected lakes with associated streams. These habitats are essential for Coho, Chinook, and Sockeye salmon at all life stages.
Species that are not native to Alaska and the Kenai Peninsula pose great threats to our ecosystem and economy. As a member of the Kenai Peninsula Cooperative Invasive Species Management Area (KP-CISMA), the Kenai Watershed Forum is involved in the eradication and control of plant species that threaten salmon-bearing streams and other salmon habitat, such as reed canarygrass, Elodea, European bird cherry, and other high-priority terrestrial invasive species.
How do invasive species spread?
Invasive species are primarily spread by human activities, often unintentionally. People, their goods, and their equipment, spread around the world very quickly. Many species can take advantage of this human movement by acting as “hitchhikers”, where their seeds and other vegetative material can latch onto boots, tire tread, and even airplane floats. Alaska’s culture of recreating, hunting, and fishing has the potential to spread invasive species far into untouched wilderness, threatening precious habitat that remains intact and undisturbed by human influence. It is essential that we learn how to identify non-native species, clean gear and equipment before and after use, and report sightings of invasive species to local experts and authorities.
Elodea
What is Elodea?
Elodea is a submerged aquatic plant with herbaceous stems, submerged leaves and floating flowers. It spreads mainly vegetatively, which means that tiny fragments of the plant are enough to start growing in a new place if light, nutrients and space is available.
Elodea photo courtesy of Wikimedia Commons
Why are we worried?
Elodea is known for its quick growth and its ability to compromise the water quality of lakes and creeks as well as severely impacting native fisheries. In places where this plant has established it makes boat and floatplane traffic very difficult. Elodea is a major concern for landowners on infested lakes or creeks since the value of their property could be reduced.
Lake survey, paddle full of Elodea
What can we do?
Never release foreign water, plants or animals into the wild. Elodea is commonly introduced to a waterbody when people dump unwanted aquariums into the water.
To prevent the spread of any invasive plants or animals, clean and dry ALL of your gear and equipment before leaving a site (waders, boats propellers, trailers, floatplanes, fishing gear, etc.). Also, be aware of the plants you are planting as many invasive plants are introduced through landscaping and gardening.
If you notice an unusual plant or animal, note the location, take a picture & call the Invasive Species Hotline: 1-877-INVASIV (1-877-468-2748).
Elodea is commonly transported from one water body to another by boats and float planes.
Reed Canary Grass
What is Reed Canary Grass?
Reed Canary Grass (RCG) is an aggressive, cool season perennial grass that typically invades wetlands that have suffered some type of disturbance. It reproduces by seeds, stem fragments and rhizomes (underground horizontal stems). Seeds adhere to moist skin or fur, and could be transported in clothing, equipment, vehicles, and wildlife.
Reed Canary Grass infestations
Why are we worried?
The impacts that RCG can have on the riverine ecosystems it invades, are many. By invading wetlands, RCG not only reduces plant and animal diversity but also destroys critical biological resources. Reed canary grass alters the geomorphology of the streams by trapping silt and constricting waterways, thus preventing salmon to reach their spawning habitats.
Reed Canary Grass growing in the middle of Beaver Creek
Management Techniques
Before any control method is implemented, the area you want to manage should be surveyed. Depending on the size, the location and the plant community of this area, there could be different methods you can apply for management purposes. Also you need to keep in mind the growth and the dispersal characteristics, as well as the life cycle of RCG when you choose a control method. Remember that you can combine different types of control methods during the same growing season. Clipping off the seed heads before any type of management is very advisable, since this will avoid creating seed banks in the ground improving your chances of eradicating RCG.
Mechanical Removal
Digging Reed Canary Grass
Bags of Reed Canary Grass that was pulled from the Kenai River
Tarping
Tarping Reed Canary Grass at Beaver Creek
Tarp ready at Beaver Creek
Herbicide Use
For large (and small) populations of RCG the only method that can achieve eradication is the use of herbicides. Glyphosate (systemic herbicide) is used for treating invasive species in natural areas due to its low toxicity and persistence. “ALWAYS READ THE LABEL. Use caution with herbicides; contact Alaska DEC or CES with questions. Always read the label, IT’S THE LAW.”
European Bird Cherry
European Bird Cherry (Prunus padus) is a tree species that was once widely planted as an ornamental in many Alaskan communities. They have large, bright white blossoms and a sweet aroma. Birds widely favor the late season fruits produced by these trees (as the name suggests), and will disperse seeds through their excrement, oftentimes very far from the original planting of the tree. A “mother” tree may stand alone without any indication it has dropped seed and reproduced- it’s offspring are more than likely hundreds of yards away, growing within thick alder and willow stand, making them indecipherable until they have matured to several feet tall. In Anchorage, where European Bird Cherry was planted widely by the municipality’s park system, European Bird Cherry has inundated several residential, salmon supporting stream systems, crowding out native vegetation.
European Bird Cherry in late season with fruit (cherries).
European Bird Cherry Tree in full bloom during summer months.
Why are we worried?
European Bird Cherry produce robust seed that can be dispersed widely by the birds that favor it. This makes tracking and monitoring infestations difficult, as seedlings of a mother tree could be miles away. European Bird Cherry grows prolifically in riparian areas and easily outcompetes and crowds out other native woody and herbaceous vegetation. This change in vegetative structure can greatly alter ecosystem dynamics and can have a cascading effect on insect and animal communities. European Bird Cherry produces hydrogen cyanide that is activated in the fall post-frost. While humans, pets, and other wild animals are unaffected by the poison, animals with segmented stomachs such as moose can die from the consumption of this plant. Multiple young moose deaths in Anchorage have been attributed to the consumption of European Bird Cherry.
European Bird Cherry Trees are identified by 2 glands (yellow bubbles) at the stem.
Bird Cherry Tree in early spring – before flowering
What can we do?
Become a Citizen Scientist and report your European Bird Cherry sightings! The Kenai Watershed Forum, in partnership with the Kenai Peninsula Cooperative Weed Management Area (KP-CWMA), is initiating a multi-year, Peninsula-wide survey for European Bird Cherry. We need citizen scientists like you to contribute sightings of European Bird Cherry! Fill out the form found in this link, or call/email our Invasive Species Specialist.
You can also participate in our Citizen Science Bicycle Survey!
Northern Pike
What is Northern Pike?
Northern pike is native to most of Alaska. However Pike do not naturally occur south and east of the Alaska Mountain Range except for a small population near Yakutat. Pike are top-level predators in aquatic food chains and are highly piscivorous (fish eating). Outside of their native range, trout, salmon and other fish have not had time to adapt defenses against pike’s predatory tactics.
Pike prefer highly vegetated, shallow habitats where they can hide and ambush prey. Lakes in Southcentral tend to be shallower than lakes in Interior and Western Alaska, and there are fewer deep water refuges in these lakes for other fish to hide.
Pike were first illegally introduced into water bodies by people. Introduced Pike are now decimating salmon and trout populations. This causes ecological damage and also negatively affects the economy by reducing recreational fishing opportunities.
ADF&G Pike Reward Poster
Why are we worried?
In Southcentral, illegally-introduced Pike can change the balance of an aquatic ecosystem because they prey on native fish while having few predators of their own. Some lakes and streams that once supported healthy numbers of Silver salmon, Chinook salmon, and Rainbow trout now have only small Northern pike. This is how illegally-stocked Pike have decreased fishing quality and threaten wild and stocked fisheries in Southcentral Alaska.
Northern Pike feeding on Salmon.
What can we do?
Never release foreign water, plants or animals into the wild.
To prevent the spread of any invasive plants or animals, clean and dry ALL of your gear and equipment before leaving a site (waders, boats propellers, trailers, floatplanes, fishing gear, etc.). Also, be aware that it is illegal to move or introduce live fish in the state of Alaska without a permit from the Alaska Department of Fish and Game.
If you notice an unusual plant or animal, note the location, take a picture & call the Invasive Species Hotline: 1-877-INVASIV (1-877-468-2748).
Other Local Invasive Species
Why are we worried?
There are a variety of invasive weed species that are slowly making their way onto the Kenai Peninsula. Because Alaska has been able to remain free from invasive species for so long, we have been able to stay ahead of the invasive curve and avoid infestations that are out-of-control. If left to spread, these terrestrial invasive species could quickly alter Alaska’s intact ecosystems, causing irreparable damage to native flora and fauna.
What can we do?
The Kenai Watershed Forum has adopted the priorities of both the Kenai Peninsula Cooperative Weed Management Area and the Kenai Peninsula Fish Habitat Partnership regarding invasive species management. The following species have been deemed priorities and are actively monitored and managed by the Kenai Watershed Forum Invasive Species Specialist. You can learn more about other terrestrial invasive species on the KP-CISMA website!
