Help to Stop an Invader!

Invasive species are a major threat to park ecosystems.  They can disrupt native species and impact biodiversity.  The staff at Voyageur Provincial Park are asking for your help to stop an invader.

Water Chestnut  

European water chestnut is an aquatic plant that grows as a dense mat that can completely cover the water’s surface. Underwater it produces a large number of filamentous leaves and has stems up to 5m long.

Water chestnut:

  • Chokes out native plants
    • Reduces oxygen levels in the water and alters the nutrient cycle
    • Provides few nutrients to wildlife
    • Severely reduces recreation opportunities particularly boating, fishing, swimming, and nature appreciation
    • Makes hard sharp seeds that are a safety hazard on beaches and shorelines

Voyageur Provincial Park is the only known location of water chestnut in Ontario.  The park’s four shallow bays support highly productive shoreline wetlands that are used extensively by wildlife and humans. It is these same bays that are being invaded by water chestnut.

Stopping the Spread

Water chestnut is an annual plant that overwinters as a seed. This means that preventing the current year’s plants from producing seeds will stop the infestation.  Seeds can lie dormant in the river for 8 to 10 years, so control over several years is needed to manage the population.

Since 2008, Ontario Parks has been taking steps to manage water chestnut. The techniques currently being used are hand-pulling, raking, and cutting and collecting. Staff can be seen using chest waders, canoes, rakes, weed-whippers, and two specially modified boats. In addition, a floating barrier is installed around the main infestation to prevent cut plants from starting new populations elsewhere. These mechanical techniques have proven to be effective in reducing the seed bank by 95% after four years of control.

Ecological Integrity

By actively controlling and eventually eradicating the population, Ontario Parks is preventing the spread of water chestnut into Ontario’s waterways, maintaining the ecological integrity of the increasingly rare shoreline wetland habitat and providing aquatic recreational opportunities to residents of Ontario and its visitors.

You Can Help!

Voyageur is looking for volunteers to work alongside park staff hand-pulling water chestnut. The park is holding Water Chestnut Pull Days on August 16, 17 and 18 from 9-3pm. If getting wet and dirty to save the environment sounds fun, then come out and volunteer.

If you would like to help out, please contact Jennifer Jung at (613) 674-2825 ext. 223 or by e-mail at or

Voyageur Provincial Park is located in eastern Ontario; halfway between Ottawa and Montreal.