Crews in northern Minnesota's Voyageurs National Park are continuing work this summer to remove large mats of invasive cattails.
The hybrid cattails spread across about 500 acres of wetlands in the park along the Canadian border.
Reid Plumb, a wildlife biologist with the National Park Service, said native cattails are beneficial wetland plants that provide nesting cover for birds, habitat for fish and aquatic insects and food for aquatic mammals.
But he said the invasive, hybrid cattails can become a problem when left unchecked.
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“When it gets rooted somewhere, it really takes over, and they create these vast swaths of just cattail and cattail only — and it's very thick,” he said. “And it doesn't really create good habitat for anything at that point.”
The hybrid can tolerate different water depths and salinity, which lets it invade and out-compete other native species such as wild rice, sedges, rushes and native cattail.
The plant can also survive and continue growing after becoming detached from the lakebed. That can result in the formation of large floating “islands,” which can become a hazard to boaters and docks.
Plumb said crews are grinding up mats of floating cattail and depositing the debris elsewhere to slow its spread.
Rather than eliminating the hybrid cattail, they are trying a long-term management plan that still maintains its ecosystem benefits.
So far, Plumb says, it has been successful.
“It's very awesome and very gratifying to see, you know, all the hard work that goes into what we do, to actually see (benefits) come out of that," he said.
He also said native species are beginning to reappear in parts of the park as more invasive cattails are removed.