Prevent phragmites from getting stranglehold

Invasive phragmites from Eurasia lines thrive in a deep ditch next to a cornfield near Dresden, Ont. The species has long been identified as phragmites australis but recent research has refuted this designation, according to Dr. Janice Gilbert. It is closely related to phragmites americanus, a species that is not an environmental concern in North America.  |  Jeffrey Carter photo

CHATHAM, Ont. — An invasive species that has spread across southern Ontario now threatens the West.

Wetland ecologist Janice Gilbert told an environmental conference Oct. 21 that invasive phragmites are a significant threat to prairie pothole, wetland, river and lake environments across southern Manitoba, Saskatchewan, Alberta and British Columbia.

The plant, which has not yet been scientifically categorized, should not be mistaken for benign phragmites americanus. The invasive species is a water’s edge plant that covers thousands of acres in some parts of Ontario, Quebec and the Maritimes.

“It’s important that we give the West a head’s up,” Gilbert said.

“I’ve talked with people from Ducks Unlimited who’ve said ducks can get into a stand of phragmites and cannot find their way out. We’ve been finding dead turtles in stands of phragmites as well.”

The species has no natural enemies in North America.

The seed can travel up to 10 kilometres, or broken plant material can float to new locations, where it may take root. Once in place, rhizomes and stolen (root-like stems) allow the species to colonize wide swaths of the landscape.

Gilbert advised western Canadians to learn about the plant and stamp it out wherever it’s found so that it does not become a permanent feature of their landscape.

“If we had known in the 1970s what an issue it would become in Ontario, we would have jumped on it, at least I hope that’s what we would have done,” she said.

Eradication efforts have had success in Ontario, but it’s an uphill battle. The strategy has been to spray glyphosate followed by rolling and a controlled burn. Spot spraying conducted the following year is important to control the escapes.

“The potential for re-growth is high,” said Pete Cloud, councillor with the Kettle and Stony Point Nation on the south shores of Lake Huron.

“Once you control an area, you need touchups every year.”

Spraying isn’t as efficient as it should be because the chemistries registered in Canada can be applied only when no standing water is present.

Gilbert said Ontario’s natural resources ministry may be close to changing that.

Formulations using glyphosate and imazapyr can both be used over water in the United States.

He said it’s possible the products have not yet been registered in Canada because the country is seen as a small market despite the prodigious phragmites population. There may also be concern that the general public will react negatively to herbicide use in wetlands.

“We’re not saying we’re going to be poisoning wetlands. It’s going to be done responsibly with safe chemicals,” she said.

“Not only is it the only option, it’s the most effective and environmentally responsible way to control phragmites.”

Gilbert believes Western Canada has an opportunity to keep the problem from spreading.

Invasive phragmites were first identified in Ontario in 1948 on Walpole Island in the St. Clair River delta, south of Lake Huron.

A concerted effort to address the issue began only in the past decade.

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