Eurasian Watermilfoil is one of the non-native species that has invaded inland lakes. (Photo courtesy of National Park Service)
Invasive plants, fish and other creatures are threatening many inland lakes. Environmentalists and property owners are trying to stop the spread…before the invaders dramatically alter the smaller bodies of water. The Great Lakes Radio Consortium’s Ann-Elise Henzl reports:
Transcript
Invasive plants, fish and other creatures are threatening many inland
lakes. Evironmentalists and property owners are trying to stop the
spread…before the invaders dramatically alter the smaller bodies of
water. The Great Lakes Radio Consortium’s Ann-Elise Henzl reports:
It’s strange to think that plants and animals from Europe, Asia and Africa
are living in small lakes in the Midwest. Boaters have taken invaders
there…after picking them up in the Great Lakes.
The big lakes are home to more than 160 aquatic invasive species,
including Eurasian Watermilfoil. The stringy plant grows in thick
clusters that get up to 12 feet tall.
“I have seen lakes where if you fell out of the boat in these massive
weeds and you weren’t wearing a life jacket, I don’t care how good a
swimmer you are, you would sink. You can not struggle your way
through these thick entanglements of weeds.”
Ted Ritter leads an effort to reduce aquatic invasive species…in
Wisconsin’s Vilas County.
(Sound of pontoon motor)
On one afternoon he takes his pontoon boat on a lake that had an
infestation of Eurasian Watermilfoil.
“It is a very aggressive plant and it has no natural predators to control its
growth, it grows up to two inches a day.”
When Eurasian Watermilfoil finds conditions it likes, it takes over
quickly. A piece as small as two inches can break off, and float away to
create a new plant.
Eurasian Watermilfoil is widespread in northern Michigan… northern
Wisconsin and other places. It’s one of dozens of aquatic invasive
species on the move in the region.
One of the worst invaders is zebra mussels. They can ravage a lake’s
ecosystem.
(Sound of motor boat)
So far, they’ve made it to just one lake in northern Wisconsin. Mike
Preul with the Lake Superior Chippewa scuba dives there, to count the
mussels. Three years ago, he found 7 adults per square meter. This year,
he counted more than 14-hundred:
“They’re still increasing. What they’ve seen in other systems is that just
like with any other exotic species they’ll come in, the population will
explode, they’ll kind of eat themselves out of house and home, and then
they’ll come down to a level and reach a steady state.”
No method has been discovered to get rid of zebra mussels, but there are
ways to control some invaders.
Herbicides can be used to kill Eurasian Watermilfoil, and some property
owners chip in to buy aquatic insects to kill the plants.
Les Schramm did that on his local lake:
“As the larvae hatches it burrows into the stem of the Eurasian
Watermilfoil and sort of eats out the center vascular part, and it falls over
and dies.”
People fighting aquatic invasive species say it’s like fighting weeds in a
garden — the work never stops and it can be expensive.
Ted Ritter of Vilas County says it costs thousands of dollars to treat a
lake once. So, often people do nothing.
Ritter says that can hurt the environment. He says it can also threaten the
economy, in areas like northern Wisconsin that rely on tourism.
Ritter says the invaders can reduce the appeal of a lake. He mentions a
plant called “curly leaf pondweed.” When it dies in the middle of
summer, it creates algae blooms that look like slimy green pillows:
“When people arrive at resorts and they look out and they see that very
unappealing lake they say ‘I’m not staying here,’ and they go somewhere
else. When realtors bring prospective buyers out to look at a property,
people get out of their car and they go right to the lake and they say ‘oh
my, I’m not even interested in looking at the house. This lake is
horrible.'”
Because it’s so difficult to control invasive species, Ritter and others
fighting the invaders focus on prevention.
Local volunteers and workers from the Wisconsin Department of Natural
Resources spend hours at boat landings. They urge people to clean their
boats, trailers, and fishing gear thoroughly when going from lake to lake,
that can keep unwanted plants and creatures from traveling along.
For the GLRC, I’m Ann-Elise Henzl.