Parade of invaders threaten inland lakes

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By Carl Stoddard

Capital News Service

In 1941, my grandparents built a small cottage on a small lake in northern Michigan. The cottage remains in the family today.

But while the ownership hasn’t changed, the lake has. Like many other inland lakes in Michigan, alien species have invaded ours

A few years ago, we started spotting clusters of zebra mussels, originally from Russia, clinging to rocks and submerged logs in the lake.

Purple loosestrife, another foreign invader, started popping up along the edges of the water.

More recently, we noticed long, feathery plants rapidly filling in parts of the lake. Eurasian milfoil, we were told.

Then we saw a new kind of reed growing along the shoreline of our little lake — a type of phragmites originally from Europe.

Concerned about these unwelcome new residents to the lake, our lake property owners association hired a lake management company to survey it and recommend possible treatment options.

In the course of its survey, the company discovered another recent arrival, tiny freshwater jellyfish. They’re originally from China.

That’s at least five invasive species that have moved into our lake.

The lake management company recommended chemical treatments that knocked back the milfoil and phragmites. Property owners can pull up the purple loosestrife.

We have to cope with the mussels. And we were told the little jellyfish are harmless.

Our lake’s problems with foreign invaders are minor compared to the plight of the Great Lakes.

The National Oceanic and Atmospheric Administration estimates that more than 180 invasive and non-native species have severely damaged the Great Lakes’ ecosystem — so far.

Although it’s less well-known, many of those invaders also have found their way into Michigan’s 11,000 inland lakes. Many rivers, streams and ponds also are affected.

“Invasive species in inland lakes are a major concern in Michigan. From zebra and quagga mussels to Eurasian watermilfoil to European frogbit, each introduction changes ecosystems and affects recreational opportunities,” said Joanne Foreman, a communications coordinator for the Michigan Department of Natural Resources’ invasive species program.

The state is heavily involved in spreading the “Clean, Drain, Dry” and “Don’t Dump Your Bait” messages to encourage boaters and anglers to reduce the spread of invasive species to inland waters, Foreman said.

Such efforts may slow the spread of invasives but can’t turn back the clock.

Curly-leaf pondweed, originally from Europe and Asia, came to Michigan’s inland waters about a century ago, said Scott Brown, executive director of the nonprofit Michigan Lake and Stream Association based in Stanton.

Eurasian milfoil has been in the state since the late 1940s, Brown said, adding, “It’s had a major effect on the (inland) lakes in the Lower Peninsula.”

And when it comes to battling milfoil and other invasives, property owners around the affected inland lakes discover they’re often on their own, Brown said.

So it’s usually up to the local property owners to come up with the money, through voluntary collections or special tax districts, to fight the invaders.

Brown said more has been spent combatting milfoil than any other invasive aquatic species in Michigan.

“It probably presents the greatest threat,” he said.

A 1954 law allows local communities to create special assessment districts. Among other things, these districts authorize communities to raise tax dollars to fight aquatic invaders.

In recent years, the Michigan Department of Environmental Quality has been issuing about 4,000 permits annually to combat aquatic nuisances, Brown said. Most of those efforts have been paid for through special assessment districts.

Each year, $30 million to $35 million is spent in Michigan on chemical treatments to control aquatic invaders, he said.

“It’s very sad. These species are irrevocably altering our lakes,” Brown said. “And hundreds of these lakes are going untreated.”

Eurasian milfoil was detected In Wexford County’s Lake Mitchell in the 1940s, Brown said. In the mid-1950s, the lake was among the first in the state to get a special tax district to control milfoil and other invasives, he said.

Mark Tonello, a DNR fisheries biologist, surveyed Lake Mitchell and issued a report on it in 2012.

“Lake Mitchell has had a Eurasian milfoil infestation for many years, requiring treatment  … on an annual basis,” Tonello wrote.

Zebra mussels were found in nearby Lake Cadillac in 2010, he said. They were then documented for the first time in Lake Mitchell in 2011, near the outlet canal that connects the two lakes.

So what should property owners do about their own lakes?

“One thought is to try and keep invasive species out in the first place. The second would be to jump on any invasions early in the process,” Tonello said.

“For example, if Eurasian milfoil shows up in a new lake, you might be able to eradicate it early on. Some exotics you can’t really do anything about — zebra mussels for example. So prevention is pretty important.”

Aquatic invasive species “are as much of a threat to inland lakes as they are in the Great Lakes,” said Andrew Tucker, a scientist who works on invasive species issues with the Nature Conservancy’s Great Lakes Project, which operates from the nonprofit’s Lansing office.

Tucker said Michigan property owners on inland lakes aren’t entirely on their own when it comes to dealing with aquatic invaders.

The state’s Invasive Species Grant Program funds various inland lakes projects, including projects that the Nature Conservancy also is working on to control invasive plants, he said.

“Michigan spends as much as $25 million annually on control of just one species, Eurasian water milfoil, and much of that is spent on inland lakes,” Tucker said.

He said detection of new invaders in the state’s inland waters, including red swamp crayfish and New Zealand mudsnails, will continue to draw attention and probably resources to Michigan and other Great Lakes states.

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