Invasive Species

No, this is not a story about UFOs.

Rather, it is about man’s failure to control the movement of plants from other parts of the world that do not belong where they have landed. In this case, the problem is Eurasian milfoil. This lake weed came from Europe, Asia and North Africa, where it is native, between the 1880s and 1940s through the aquarium trade and/or shipping, most likely through the St. Lawrence Seaway. It is carried inland by boats that pick it up on their props, whose boat owners fail to clean their boats and then bring the weed to other lakes.

The result is that since they are not native species, invasives crowd out the native plant life resulting in potentially devastating impact on the other aquatic life (fish, frogs, turtles, etc…) which survive on the native plant life. In addition, since they have no natural way to limit their growth in their new environment, they grow rapidly and create hazards for boating and other recreational activities.

Goose Lake, in Central Wisconsin, where I live, and serve as Chair the Goose Lake Watershed District (GLWD), runs its own weed harvesting program to keep the lake open for boating and recreation, operating under a permit from the DNR which preserves sensitive areas near the wetlands. We have known that we have had Eurasian milfoil in our lake for many years. Before the creation of the GLWD 12 years ago, the Goose Lake Improvement Association used to hire a contractor to spray it with herbicide. Given how sensitive and precious our environment is, the GLWD shifted to biologic control using beetles that ate away at the Eurasian milfoil. This worked for awhile, but it was a very labor intensive process, and finding volunteers to hand place beetles on the milfoil was challenging.

Subsequently, the water level dropped significantly, we had some hard freezes, and the invasive species problem seemed to be under control. However, this year, for reasons that are unclear, the Eurasian milfoil came back with a vengeance. We have already harvested a record tonnage of weeds in an effort to keep the growth in check and allow the lake to be usable. But it has been a challenge.

So, the GLWD contacted the DNR and gave them a tour of the problem. DNR staff agreed it was problematic and advised us that we would likely have to use herbicide next spring to control the invasive species. As an environmentalist who cherishes clean water, I do not relish the idea of putting herbicide in our lake. However, the alternatives are not good. If we do not get on top of the invasive weeds soon, they will take over the lake and throw the entire eco-system off kilter.

This afternoon, I took my canoe out and found the DNR staff conducting a lake plant survey, which is a necessary step to obtaining a permit for applying herbicide. It will take them all day, and they let me know that they had already found 30 types of native species of plants in the lake. Unfortunately, as expected, they also found plenty of Eurasian milfoil.

The area shown above has been harvested so the DNR staff use the long pole you see to gather weeds down below the surface. Closer to our property, these photos show the diverse plant life near the wetlands that indicate a healthy lake put in danger by invasive species.

The DNR will report back to me soon with advice on how to battle the Eurasian milfoil in the least toxic manner possible. When I spoke with them previously, they advised a low level application of herbicide in the early spring so that native species are not impacted. Then, they will come back the following year to survey the plant growth and advise on next steps from there. If we are successful, we may be able to hand pull the invasive species in the future, possibly with the help of divers in deeper areas.

The GLWD Annual meeting is coming up over Labor Day weekend, when we will discuss this and other topics as we continue our successful effort at small “d” democracy. If we all work together, hopefully, we can maintain Goose Lake’s natural balance for generations to come.


For more information on how I can help you accomplish progressive, effective systems change, contact me, Jeff Spitzer-Resnick by visiting my web site: Systems Change Consulting.

Categories Environmental Protection, Invasive speciesTags ,

2 thoughts on “Invasive Species

  1. Looks a bit like seaweed. Is it edible? Does it have any useful purpose after being harvested?

    1. It isn’t edible by humans, although fish and insects nibble at it. However, it is great garden mulch which is what I use it for from the weeds I rake and hand pull from our small beach. As my Weed Harvesting post mentions, the larger tonnage that we machine harvest goes to a nearby farmer who composts the weeds into his fields.

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