NR 40 New Species Consideration – Submit Your Recommendations Now!

The Wisconsin Invasive Species Council is currently taking recommendations for species to be considered for potential regulation under Wisconsin’s invasive species rule, ch. NR 40.  Chapter NR 40 first went into effect in 2009, and was last revised in 2015.  More information on this rule can be found here.  Efforts are currently underway to compile new potentially invasive species to assess, establish species assessment groups (SAGs) to review these species for potential regulation, and ultimately revise the existing ch. NR 40 rule based on the recommendations of the SAGs and Wisconsin Invasive Species Council.

Please fill out this survey link if you have any species nominations to consider for regulation under the revised ch. NR 40 rule.  Note that many invasive species are already regulated under NR 40, so check the current list of regulated species to see if your suggestion is already listed.  In addition to new species to consider, you can also nominate a species for re-assessment (i.e., moving from prohibited to restricted; or restricted to non regulated), or make any other suggested changes to the rule.

The deadline for submitting species nominations or suggesting other changes to the rule is midnight on Friday, January 4, 2019.

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Comments sought on DNR strategic analysis of aquatic plant management in the state

Contacts:  Carroll Schaal, lakes and rivers section chief, 608-261-6423 or James Pardee, environmental analyst, 608-316-0999

MADISON—The Department of Natural Resources invites the public to comment on its draft Strategic Analysis of Aquatic Plant Management (APM) in Wisconsin. The report, which summarizes current information on APM in the state, serves as an informational resource to help decision-makers and the public to better understand the topic and to aid in the development of future APM policy.

Aquatic plants are a critical part of the state’s freshwater environment. They help to ensure good water quality and clarity, provide habitat and food for fish and wildlife, and serve many other valuable functions. Sometimes, though, aquatic plants can become overabundant and interfere with water uses. Managing these problems is complicated by the fact that some of the DNR rules governing APM have not been updated since 1986, while APM practices and challenges have evolved.

The draft Strategic Analysis report and links to more information about APM can be found on the department’s APM strategic analysis webpage, or by searching for the key words “aquatic plant management” on the department website,

Comments on this strategic analysis may be submitted through January 25, 2019, by email to or sent via US Mail to Carroll Schaal, lakes and rivers section chief, 101 S. Webster Street, Madison, WI 53707-7921.

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Hybrid Milfoil: Coming to a Lake Near You?

Post by Sara Fox, Aquatic Invasive Species Outreach Assistant, University of Wisconsin-Extension. This post was originally featured on the UW-Sea Grant Blog. 

This summer, while water skiing in Waukesha County, Wisconsin, I recall taking a massive wipeout. I remember expecting to feel the painful sting after hitting the water, similar to that of a belly flop. Instead, I landed on a cushion of plants. I looked around and found myself floating on top of a giant mat of milfoil!

If you’re a Wisconsin lake user, patches of milfoil probably aren’t new to you. However, a new milfoil hybrid combines genes of native and invasive species and may be a cause for concern on some Wisconsin lakes.

Wisconsin has many native milfoil species that provide cover and sometimes food for fish, invertebrates and aquatic insects. Milfoil species such as northern or whorled watermilfoil are native to Wisconsin and have contributed to lake ecosystems for a long time. More recently, in the early 1960s an invasive milfoil species called Eurasian watermilfoil was discovered in Dane County and since has spread to over 800 lakes in Wisconsin.

A diver surfaces through a heavy infestation of Eurasian watermilfoil.

As its name suggests, Eurasian watermilfoil is native to Europe, Asia and North Africa. Like many other plants, Eurasian watermilfoil grows up to the surface to access sunlight. Yet, unlike many other plants, it doesn’t stop at the surface; it grows across the surface, causing dense mats of vegetation that can get tangled in boat propellers and block sunlight from native plants below.

Eurasian watermilfoil can spread quickly and efficiently, primarily because of its ability to produce adventitious roots after fragmenting. This means that if you cut a strand of Eurasian watermilfoil into ten pieces, each piece could sprout new roots and become its own plant.

Treatment options for lakes that contain Eurasian watermilfoil differ by lake and vary by levels of efficacy, cost, benefits, and drawbacks. Attempted treatments have included: chemical application, manual hand pulling and use of biological control weevils.

Even more recently, a hybrid milfoil has evolved on some lakes in Wisconsin and it might be a big deal. The hybrid (sometimes referred to as a “super milfoil”) is a genetic cross between native northern watermilfoil and invasive Eurasian watermilfoil. It exhibits characteristics similar to both northern and Eurasian watermilfoil and genetic testing is often needed to verify its presence.

A possible hybrid species collected and pressed in Jefferson County, Wisconsin.

The hybrid species hasn’t caused any verified negative effects to lake ecosystems that differ from Eurasian watermilfoil, but it’s potential to cause trouble for lake users in coming years makes it worth keeping an eye on. For example, state biologists have observed that the hybrid may be harder to control using the chemical application methods we use to treat Eurasian watermilfoil. Specifically, in some cases, it has shown a reduced sensitivity to  2, 4-D and fluridone. (It’s important to note that if your lake hasn’t seen success treating for Eurasian watermilfoil it doesn’t necessarily mean you have the hybrid.)

Additionally, the hybrid’s growing habits seem to have a competitive advantage over both its parents. Expect more information on the hybrid’s behavior soon from organizations conducting research such as the University of Minnesota Aquatic Invasive Species Research Center and the Wisconsin DNR Aquatic Plant Management Program.

If you’re worried about hybrid milfoil making its way into a lake you care about, don’t panic! There are preventative measures individual lake users can take to make sure hybrid milfoil–and every other aquatic invasive species–doesn’t enter a new waterbody:

  • INSPECT your boat, trailer and equipment.
  • REMOVE any attached aquatic plants or animals (before launching, after loading and before transporting on a public highway)
  • DRAIN all water from boats, motors and all equipment
  • NEVER MOVE live fish or plants away from a waterbody.
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Starry Stonewort: Up-And-Coming AIS of Wisconsin

Post by Bradley Steckart, Waukesha and Washington County AIS Coordinator; adapted by Sara Fox, UW-Extension

Starry Stonewort (Nitellopsis obtusa) has made a name for itself in Wisconsin as a well-known invasive species. Questions surrounding its unknown impacts and the viability of its reproductive bulbils have researchers, scientists, and volunteers interested in this relatively new invader. N. obtusa is a prohibited aquatic invasive species currently present in four Wisconsin counties. Here’s what you need to know about starry stonewort: 

What is it?

Starry stonewort is a freshwater macroalgae native to Europe and western Asia. While it is classified as invasive in the Midwest, it is listed as endangered in its native habitat. You might confuse starry stonewort with native stonewort (Chara spp.) or muskgrass (Nitella spp.) and pondweeds such as sago pondweed. 

You can identify starry stonewort by it’s bright green branches that grow in whorls of 4-6 around the stem. It is named after its small, white, star-shaped reproductive structures called bulbils. These bulbils reside 1-3 inches deep in the sediment and act as an anchor for the alga. Starry stonewort is dioecious, meaning that male and female reproductive structures grow on seperate algal stalks. Currently, only males are present in the United States indicating that reproduction is only occurring asexually by bulbil production.

The star-shaped reproductive structure of starry stonewort is called a bulbil. Credit – Paul Skawinski

How might it affect me?

Like many other invasive species, starry stonewort holds potential to outcompete native vegetation and alter the ecosystem of the waterbody where it is introduced. Starry stonewort grows into dense vegetative mats that can interfere with recreational water activities like tubing or water skiing. Large patches of starry stonewort may also threaten fish spawning habitat. However, those impacts are inferred from the impacts of other invasive aquatic plants. The specific effects of starry stonewort on fisheries is largely unknown and is currently under investigation by leading scientists.

As always, it is beneficial to take preventative measures to avoid spreading starry stonewort and other aquatic invasive species to and from your lake.

Starry stonewort can outcompete native plant species in a waterbody. Credit – Paul Skawinski

What does this mean for Wisconsin Lakes?

Manual and chemical control methods have been used to treat starry stonewort with varying success. However, boaters and anglers can take individual action to prevent the spread by following Wisconsin DNR AIS prevention steps:

INSPECT your watercraft vehicles and trailers for plant fragments upon exit and entrance to a waterbody. Pay special attention to anchors and footwear where bulbils might reside. Hunters should make sure to inspect duck decoys and blinds.

DRAIN water from your boat. This includes livewells, motors, and bait containers filled with water from the waterbody you’re exiting.

REMOVE all attached plants from your watercraft vehicles and trailers.

NEVER MOVE plants or water among waterbodies. Not only is this effective, but enforced by Wisconsin law.

For more information on starry stonewort, check out WDNR or UWEX Lakes resources.

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