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Taking a stab at Flowering Rush

TESTING THE WATERS of Big Detroit Lake is Mississippi State University researcher John Madsen, who was checking dissipation levels of red dye to determine the amount of herbicide still in the water. Madsen and two other researchers are studying which herbicide works best on certain aquatic invasive species.1 / 2
flowering rush is an aquatic invasive plant that can squeeze out native plants and alter fish species in a lake if left to flourish.2 / 2

John Madsen knows all too well the nasty effects invasive species can have on lakes -- it's what the Mississippi State University researcher does for a living.

That's why the Pelican River Watershed District contracted his services, along with a researcher from Concordia College in Moorhead and a representative from the Army Corps of Engineers.

The crew was in town last week to find out more about aquatic invasive species in the lakes region.

A big part of their study, which began last summer, is happening on Detroit Lake, where flowering rush is growing like wildfire.

Madsen, who is with the Geosystems Research Institute, says their goal is to find out how certain herbicide work on aquatic invasive species like flowering rush.

There has been a growing sense of urgency among local lake associations to light a fire underneath the Minnesota DNR to help them better fight invasive species at every level, and Madsen says their concerns should be taken seriously if Detroit Lakes area residents want to save themselves from a very costly mistake.

"In biology there are three different phases of species growth," explains Madsen, who studies "aquatic hitchhikers" all over the U.S., "there is the slow growth phase, which can take years, then the rapid growth, then once the species has consumed the habitat's resources, it starts to slow down again -- right now I believe you've just entered the rapid growth stage here."

Madsen says flowering rush, a nuisance plant that can grow both above and below water, not only clogs boat motors, but also kills native plants and completely alters the type of fish that a lake can sustain.

"It's displacing habitat that's important for the spawning of trout and is conducive to pike, so it changes the lake into a northern pike fishery," said Madsen, a scenario that local fisherman say is not desirable.

Madsen says it's understandable that many residents here have kept a false sense of security because it's still tough to notice the effects locally due to a variety of fish in these lakes, but he warns inaction will lead to a costly shift in habitat.

"It's not too late, but there needs to be a change in the attitude here," said Madsen.

The researcher says the main two things that will determine whether or not an area successfully combats invasive species is support at the state level (with the legislature and the DNR) and how well local organizations work with those agencies.

"Local entities can either be a great help to management or slow it down," said Madsen.

Luke Skinner, supervisor of the Minnesota DNR's Invasive Species Program, shares that opinion and says right now speeding up the process is difficult because of a budget battle and head butting between agencies that ultimately want the same thing -- to fight invasive species.

"We couldn't do this without the local lake associations, but it is a challenge when you're working with different organizations that have differing opinions on how things should be done."

Pelican River Watershed Administrator Tera Guetter admits she's been frustrated with the state's slow response to invasive species, but says there are still some plans being executed through teamwork.

"DNR has awarded the district $30,000 to help us pay for the research (with Madsen's team); we are hoping to spray anything emergent near the shore within the next couple of weeks, and the city of Detroit Lakes is treating the flowering rush in its submergent form," Guetter said.

She adds that because Minnesota has been too lax in responding to the invasive species problem, Guetter believes the best thing that can be done now is find out what laws and policies Wisconsin and North Dakota have, then do that.

Madsen agrees, saying he's seen the economic impact that aquatic invasive species can have on communities, and recommends a more rapid response here.

"If there is a new plant found, even if you don't know it's going to spread, it's so much easier to stop it when it's small rather than waiting to see what happens."

Meanwhile, Madsen and his partners continue to research and analyze local lakes.

His crew hit Big and Little Detroit, Sallie, Curfman and Melissa lakes late last week, taking water and soil samples where flowering rush is growing.

"How long does it continue to grow? Does it die in the fall? How is it spread? How does soil depth or sediments affect it? What kind of herbicide most efficiently kills it and how much does it take? These are all things we want to find out because right now there is so little known about flowering rush -- it's fairly rare," said Madsen.

The researchers treated four different lake plots, measuring the effectiveness of different herbicide.

Their goal is to pinpoint exactly how to most effectively target flowering rush and its fellow invasive species so that local officials have one more weapon in their battle against the unwanted aquatic hitchhikers.

The crew will be back again in August for another round of research.