Although a pretty plant, purple loosestrife crowds out native plants necessary for wildlife habitat. (Photo by Roger F. Thoma)
We’ve all heard about exotic species invading the Great Lakes states. Zebra mussels, gypsy moths, and Asian carp all pose serious threats to the ecosystems they invade, but insects and fish aren’t the only unwelcome visitors. Invasive plants are also creeping in. One U.S. Forest Service biologist is hoping to recruit a small army of volunteers to help him keep the invasive weeds under control. The Great Lakes Radio Consortium’s Stephanie Hemphill reports:
Transcript
We’ve all heard about exotic species invading the Great Lakes states. Zebra mussels, gypsy
moths, and Asian carp all pose serious threats to the ecosystems they invade. But insects and
fish aren’t the only unwelcome visitors. Plants that don’t belong in Great Lakes forests are
creeping in. One U.S. Forest Service biologist is hoping to recruit a small army of volunteers to
help him keep the invasive weeds under control. The Great Lakes Radio Consortium’s Stephanie
Hemphill reports:
Jack Greenlee wades through chest-high grasses, rushes, wild raspberries and roses. He reaches
for a clump of lacy plants with soft purple flowers. He yanks one out of the ground.
“It’s got an extensive root system, big & woody. The plant itself is 6 feet tall, these spikes of
beautiful light purple flowers, lots of them, so very eye-catching.”
It’s purple loosestrife, and it’s invading everywhere – including Johnson Creek, in the Superior
National Forest, north of Duluth Minnesota. The creek flows into a wetland here, near a
highway.
This area is a favorite spot for mallards and other water birds. But Greenlee says the loosestrife
could change that.
“As the invasion of a marsh progresses, there’s more and more loosestrife and fewer and fewer
native marsh plants – consequently fewer resources for waterfowl that might stop.”
That’s because loosestrife isn’t on the menu for a mallard.
Purple loosestrife is one of several plants that arrived in North America in grain shipments a
hundred years ago. They’ve been spreading across the continent since then. Some – like
loosestrife – have also been grown in gardens.
“It came from Europe, and there are different insects that eat the plant there, but when it was
brought here, the insects didn’t come along. There’s no insect predators, viruses, molds – so
consequently, it’s able to thrive.”
Because they have no natural predators, the exotic plants can shoulder aside the native ones.
That can affect everything in the complex web of life.
“Once they’re there, they’ll always be there, can’t ever restore truly to what used to be. always be
component, so aggressive and hard to get rid of. So it’s kind of a one-way street.”
(walking)
Greenlee is taking an inventory of all the non-native plants in the Superior National Forest. He
says they usually show up along roads and other places where the land is already disturbed.
People bring them, without knowing it, on their tires or their boats.
“And here’s another species we’re tracking; it’s common tansy.”
These kinds of exotic plants are causing a lot of problems around the Great Lakes. The remote
parts of the Superior National Forest aren’t too badly infested yet.
So Greenlee is training a cadre of vigilantes to keep an eye out for non-natives, especially in the
Boundary Waters Canoe Area Wilderness.
“It’s a large, pretty intact ecosystem without a lot of invasives yet. It’s a lot harder to get into,
there’s not a lot of people driving down the roads, so the more eyes the better.”
So far, about a dozen people have volunteered. Hikers, and other people who enjoy the outdoors,
people concerned about preserving the unique wilderness of the Boundary Waters. They spent a
day learning how to recognize purple loosestrife, tansy, and the other invasive non-natives.
Greenlee tells his recruits to report to him when they see some, or even to pull them up.
“We’ve had patches pulled in before, our seasonal crews revisit sites & don’t see them after
pulling them. when you have small infestations, can be effective.”
Greenlee hopes next year more people will want to join his volunteer team, and help him prevent
a major infestation of non-native invasive plants in the Superior National Forest.
For the Great Lakes Radio Consortium, I’m Stephanie Hemphill.