Nature Conservancy warns of invasive plants in Saint John-area wetlands

Some rare plants and animals have new invasive species to contend with in Saint John area wetlands, according to research from the Nature Conservancy of Canada.

Reed canary grass was found in almost all of the 12 large coastal wetlands studied by the group over the past three summers, said conservation biologist Allison Patrick.

As well, a plant called brass buttons, native to southern Africa and New Zealand, was found widespread in Red Head marsh and Musquash estuary.

"The main threat we have observed so far," said Patrick, "is that the invasive plants have crowded out many of the native ones."

The other sites studied include Randolph Island, Milford, Saints Rest, Belmont and Ragged Point.

It was "really neat" to see how the wetlands "were refuges for wildlife within the city," she said.

Native to the wetlands, said Patrick, are green ash trees, red goosefoot plants, Nelson's sparrows, deer, shorebirds, ducks and herons — species of concern for conservation.

Besides habitat, wetlands also provide other "eco-system services," she said, such as filtering water, buffering storm waves and storing carbon. She described them as "giant sponges" or "kidneys."

"They really are helpful for protecting our shorelines and reducing the effects of flooding," said Patrick. 

Because of all that, it's of particular concern when an invasive species gets into a wetland, said Kristin Elton, program director at the New Brunswick Invasive Species Council, a relatively new non-governmental organization in the province, which got its first full-time staff in 2019.

Changes in these areas can have "drastic impacts," she said.

If the plant composition changes, for example, a marsh may not be able to absorb as much water.

Part of the council's role is to raise awareness of invasive species, said Elton.

And reed canary grass is on its radar.

The plant has been known to get into wetland areas and "kind of takes over everything," she said.

Reed canary grass has been documented in many places in the province since 2017.

There are 112 reports of it on iNaturalist.ca, in locations including Sussex, Fredericton, St. Quentin, Restigouche, Miramichi, Shediac, Cocagne, the Acadian Peninsula, Sackville, Moncton, Fundy Park and Saint John.

But Patrick said she was surprised by how much she found.

They're asking people to upload photos to the i-Naturalist app if they find it, to help determine how far it's gone.

They already know it's growing along the St. John River and in the Belleisle Bay area.

It may be too late to eradicate it, but even if that's the case, things could be done to try to prevent it from spreading more, they said.

It also came as a surprise, said Patrick to see how widespread brass buttons were at Red Head. 

They had only been seen growing in small clumps in the Musquash area.

"Now we can keep track of it," she said, and do something about it if it seems to be spreading quite a bit."

Both reed canary grass and brass buttons should be studied further, said Patrick, to better understand the impacts on Saint John wetlands.

An estimated 90 per cent of wetlands around the world have been degraded, she said.

"We really need to keep the wetlands that we have left."

"They're difficult to replace."

What to do?

The Nature Conservancy will share the results of its study with participating landowners, said Patrick, along with recommendations to protect wetlands on their property. 

They're not being asked to try to tear out invasive species on their own because wetlands are sensitive areas.

But they can do other things to help, said Patrick, like cutting back on pesticides and putting up boxes for bats or ducks.

Elton has other tips for the public to avoid accidentally spreading invasive species.

One of the council's slogans is "play, clean, go."

She recommends taking a brush along and using it before leaving a recreational area because seeds, bugs and egg sacks can get stuck on bike tires, shoes and dogs.

The council also asks people not to move firewood and to clean and dry boats before launching in a different waterway.