Controlling a killer (Ecological Management)

Curly leaf pondweed is well-adapted to be an invasive species (if you've forgotten, check out the ADAPTATIONS page to refresh your memory)! Although it was originally introduced to the United States as an aquarium plant and duck food (it was originally planted in Michigan lakes as a food source for ducks), it can now be found in almost every state of the US as well as in New Zealand, Europe, and Africa. In fact, curly leaf pondweed is actually a pretty popular organism; it has made headlines across the world as an invasive species! Read more about these invasions in the Winnipeg Press of North Dakota, the Journal Gazette of Fort Wayne, Indiana, the Eden Prairie News in Minnesota, WEAU of Eau Claire, Wisconsin, and in the Star Tribune of Minneapolis! Curly leaf pondweed was also put on a "black list" of invasive species in Britain (THAT article can be found by clicking HERE)!

 Because this plant is SO successful at taking over native submerged-plant communities, curly leaf pondweed is considered extremely harmful. Its early growth and quick maturity often block sunlight for other native species and its early die-off leaves mats of decomposing curly leaf pondweed on the surface of the lake. As these plants break down, they add phosphorus and other nutrients to the water. The addition of these nutrients dramatically increase the potential for algal blooms within the lake!

So what can be done to stop the inevitable madness of this submerged macrophyte monster? Early methods of controlling this invasive species include hand-pulling the weeds and the prevention of spreading fragments. Often times, pieces of curly leaf pondweed attached to a boat or trailer often fall near boat launches where there is little competition. Efforts to prevent this spread may help to stop curly leaf from taking over many more lakes across the world!

Once curly leaf pondweed has become an established community within a particular ecosystem, herbicidal treatments are often used to eradicate the species entirely! Before this is done, a lake management plan, which includes the mapping of curly leaf pondweed populations and other environmental factors, is performed to determine how long the treatment should be given to the lake. This is a risky procedure as these herbicides often hurt other aquatic plant life besides the devious Potamogeton crispus. Often times, certain parts of lakes are quarantined to avoid the spread of curly leaf pondweed. These areas are often marked or mapped out by local or state regulators like the DNR.

Other techniques to rid an ecosystem of curly leaf pondweed include dredging (pictured to the right), drawdown, and benthic barriers. Dredging is often used in lakes that have been filled with sediments or the removal of certain toxic substances. This is an expensive technique and is often used on lakes that are in need of aquatic plant management AND lake remediation. Drawdown is a form of management that involves removing water to a certain depth. It is most effective if used for at least one month. Although this method is inexpensive, it can have harmful long-term effects on other populations of plants and animals that live in the ecosystem. Benthic barriers cover a layer of the submerged plant to prevent them from growing. Eventually, new plants will grow on top of this barrier. Occasionally gasses from the decomposing plants underneath the barrier force the barrier off of the layer of plants. Talk about resistance!


It's important to educate people about how curly leaf pondweed spreads through lake communities. Once a population of this invasive species has been removed from the environment, it's crucial to inform local communities about how to keep this plant out!

Many states in the United States offer special plans to prevent the spread of curly leaf pondweed within their lakes. In the Midwest, the Wisconsin DNR offers guidance for dealing with many invasive species (which can be found by clicking HERE). Minnesota offers a specialized pamphlet for the treatment of curly leaf pondweed (check it out)!. 

Who would've guessed this plant was such a nuisance?

What do YOU think of when you hear the word pupuke? Continue on to FACTS to discover what this strange word actually means!