Treatment for Eurasian milfoil holds for five years, restoring popular lake to health
By Todd S. Bergmann, Valders Journal
Jan 22, 2022
Reprinted with permission. Please subscribe to the Valders Journal and follow the Valders Journal on facebook.
Treatment aimed to kill invasive Eurasian milfoil in Pigeon Lake had an unusual result–it worked.
Gus Gospodarek, president of the Pigeon Lake Association, said a recent consultant’s report shows improvement in the rural Valders lake because of treatment for the invasive aquatic plant a few years ago. “We are weed free so far,” he said.
The report produced by Onterra Lake Management Planning noted treatment took place in 2017. “We are thrilled about it,” Gospodarek said. “That will be five years without the finding of Eurasian milfoil.”
The association monitors water quality and the presence of Eurasian milfoil and also hires a biologist to measure several facets of water quality and produce an annual report.
“It’s our report card,” he said. “It tells everything about the good, the bad and the ugly. We’ve got an A-plus.” Tom Ward, an environment expert who recently moved from this area to Vilas County, said treatments subdue but seldom eradicate Eurasian milfoil. “Generally, it comes back,” he said. “Not that it won’t.”
In Pigeon Lake, unlike in other lakes, Eurasian milfoil has not returned after several years, Ward said. Gospodarek said he expects the invader to return at some point. “It is just a matter of when,” he said.
Eurasian milfoil invades lakes, rivers and ponds, thrives in areas which had natural or man-made disturbances, exists at any temperature, and forms large, floating mats of vegetation, which impede water traffic and prevent light from reaching native species, according to the state Department of Natural Resources.
Pigeon Lake had all these problems with the plant, Gospodarek said. “We had quite a bit of matting on the lake,” he said. “You could not push a kayak through it.”
As noted in the report, the presence of native species in Pigeon Lake shows it is healthy, Ward said. “A lake that has been invaded by species will have only two or three native species,” he said. “This one has 21.”
Normally, the invasive species themselves or the chemical used to eradicate them will kill the native species, Ward said. Although herbicide did reduce populations of native species, he said these all recovered by 2021.
Gospodarek said he likes the return of native plants to the lake. “Right now, we are at a high point of what the good species of plants are supposed to be,” he said. “We do not have weeds that are taking over like an invasive species does. “When you get an invasive species, it takes over and clears out other plants.”
When people try to eradicate these powergrabbing invasive species, Ward said native plants may get knocked down. “There was a little of that in 2018,” he said. “But, it looks like it all came back.” One native plant that returned is watermilfoil, Ward said. “That’s a good sign that they were not knocked out completely by the invasive,” he said.
Northern and similar watermilfoils provide cover for fish, and do not take over the lake bottom, Gospodarek said. The muskgrass population of Pigeon Lake has increased since 2012, following a sevenyear decline, the report states.
Muskgrass ties up phosphorous to keep it from polluting the lake, Ward said. Gospodarek calls muskgrass, “good weeds.” Other desirable weeds, such as slender and southern naiads, had steadily declined since 2011, with an increase from 2017 to 2018 following treatment, the Onterra report said. Slender naiad is a source of food for migratory waterfowl.
Gospodarek said he has seen good numbers of geese and ducks on Pigeon Lake. “It is pretty cool to see them,” he said.
Similarly, the report said that Illinois pondweed had a significant increase from 2018 to 2021. Despite its name, Gospodarek said Illinois pondweed is a good weed and native to Pigeon Lake.
In early stages of treatment for Eurasian milfoil, Ward said some fishermen were concerned that treatment would hurt the fishery. “The fact that we have a strong native plant community will provide for a better fishery,” he said. With Eurasian milfoil in the lake, Ward said predator fish often could not get at other fish, which can stunt their growth.
Since the Eurasian milfoil treatment, Gospodarek said he has seen an increase in fishermen using the boat landing. “Fish are plentiful,” he said. “We have bass, crappies, bluegills and northerns. There are some walleyes that have been caught. “We have a lot of activity from fishermen to kayakers to people who bring sailboats and paddle boats. It is a very active lake because people like the clarity.”
Because of recent efforts, Ward said the water clarity of Pigeon Lake is good down for more than 20 feet. This compares to Silver Lake, where the water quality is good until just four or five feet. “Good water clarity provides good habitat,” he said. Pigeon and Cedar lakes are the tops in water quality in Manitowoc County, Ward said.
Likewise, Gospodarek said he notices improved health of Pigeon Lake. “We’ve got a great healthy lake,” he said. “It is what we are proud of. That is why we work on it every day.” In addition to chemical treatment, Gospodarek said that inspections of boat bottoms for invasive species have also made Pigeon Lake better for users and native species.
Gospodarek said the association will continue to monitor the lake for Eurasian milfoil. While he sees no need for further treatments, Gospodarek said if future surveys show Eurasian milfoil has returned, the association “will begin the fight again.”
“The fight will consist of monitoring and zeroing in on the areas where the milfoil is and the areas where it was years ago,” he said. “It will probably come up where it existed in the past.”