WI Lakes.net 2026 AIS Briefing

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Aquatic invasive species (AIS) continue to pose some of the most significant ecological and economic threats to inland lakes across the Upper Midwest. With their ability to outcompete native species, disrupt food webs, damage habitat, and impair recreation, staying informed is essential for lake associations, anglers, paddlers, and waterfront property owners.

This 2026 update highlights key AIS concerns for Wisconsin—our primary focus—and provides a look at emerging and ongoing threats in Minnesota, Michigan, and Illinois. The annual cost to combat AIS in WI is expected to push beyond $13M given past costs. This reflects cost to combat and not necessarily the true ecological impact (displaced species, lost opportunity, disrupted cycles, etc).

This figure reflects statewide investments that include:

  • Monitoring and early detection
  • Watercraft inspection and decontamination
  • Local lake grants and rapid response funding
  • Enforcement of AIS transport laws
  • Outreach and education programs

AIS in Wisconsin: Current Species of Concern

Wisconsin’s Department of Natural Resources continues active AIS monitoring across the state’s waterbodies. Citizen monitors and partners play a central role in discovering new infestations and tracking established species. Many of these species fall under Wisconsin’s NR 40 invasive species rule, which classifies harmful plants, animals, algae, and pathogens. [dnr.wisconsin.gov]

Most Prevalent Aquatic Invasive Plants in Wisconsin

The following AIS plants remain widespread concerns, frequently appearing in verified waterbody lists across the state: [apps.dnr.wi.gov]

  • Eurasian Watermilfoil (Myriophyllum spicatum)
    Forms dense mats, inhibits boating, and crowds out native plants.
  • Curly-Leaf Pondweed (Potamogeton crispus)
    Early-season growth shades natives; sharp die-offs degrade water quality.
  • Purple Loosestrife (Lythrum salicaria)
    A wetland invader that displaces native vegetation and reduces habitat value.
  • Brittle Waternymph (Najas minor)
    A fast-spreading submerged annual found in many southern and central Wisconsin lakes.
  • Starry Stonewort (Nitellopsis obtusa)
    An invasive alga forming dense, star-shaped bulbils; increasingly detected in Wisconsin. [storage.go…leapis.com]

    High‑Risk or Restricted AIS Plants Under NR 40

    The state identifies additional prohibited or restricted species that require rapid response if detected:
    Hydrilla, Brazilian Waterweed, European Frog-bit, Parrot Feather, Yellow Floating Heart, Water Chestnut, and others. [storage.go…leapis.com]

    Aquatic Invasive Animals of Concern in Wisconsin

    Key faunal invaders documented across Wisconsin waterbodies include: [apps.dnr.wi.gov]

    • Zebra Mussels (Dreissena polymorpha) – Sharp-shelled filter feeders that alter water clarity and ecological balance.
    • Chinese & Banded Mystery Snails – Compete with native snails and degrade beach quality.
    • Rusty Crayfish (Faxonius rusticus) – Aggressively displaces native crayfish; destroys aquatic plant beds.
    • Invasive fish concerns, including introductions of Round Goby and Carp species, remain regionally relevant.

    How Wisconsin Manages AIS

    Wisconsin’s AIS strategy includes rapid detection, NR 40 enforcement, educational outreach, and lake-by-lake management permits for plant control. Citizens can report sightings via the DNR’s online reporting tool.

    Minnesota: Rising AIS Challenges and Notable Trends

    Minnesota remains a national hotspot for AIS research and early detection thanks to the Minnesota Aquatic Invasive Species Research Center (MAISRC) and the Minnesota DNR.

    Key Minnesota AIS Issues

    • Zebra Mussels: Widespread; recent studies link their presence to elevated mercury levels in fish, raising human health concerns. [lakeindependence.org]
    • Prohibited Invasive Species Expansion: Minnesota DNR recently classified 13 high‑risk AIS as prohibited to prevent introduction and spread. [invasivesp…esinfo.gov]
    • Invasive Carp Management: The state continues aggressive prevention efforts to keep carp species from expanding into northern lakes and rivers.

    Minnesota Monitoring and Data

    Minnesota maintains a continually updated AIS database covering occurrences of invasive plants, fish, invertebrates, and diseases. [mnatlas.org]

    Michigan: Watch Lists, Plant Threats, and Early Detection Priorities

    Michigan’s program emphasizes early detection and rapid response, supported by extensive watch lists and detection campaigns.

    Michigan Watch List Aquatic Invasive Species

    Michigan has designated 18 aquatic invasive species as high-risk, including:

    • 10 aquatic plants
    • 5 fish species
    • 2 crayfish species
    • New Zealand Mudsnail
      Efforts include public reporting via MISIN and statewide BioBlitz events. [michiganfarmnews.com]

    Notable Aquatic Plant Threats in Michigan

    Michigan’s watch list and field guides highlight plants with limited distribution but high invasion potential, including:
    Brazilian Elodea, European Frog-bit, Hydrilla, Water Chestnut, Yellow Floating Heart, Parrot Feather, and others. [lssu.edu]

    Statewide Program Focus

    Michigan’s inter-agency Invasive Species Program addresses species that threaten local ecosystems, focusing on early detection and rapid response to prevent establishment. [michigan.gov]

    Illinois: Key AIS Concerns in the Great Lakes and Statewide

    Illinois is a critical geographic link between the Mississippi River system and the Great Lakes, making it a priority region for invasive carp prevention and aquatic species management.

    Major Aquatic Invasives in Illinois

    Illinois Extension highlights several unregulated yet concerning AIS, including:
    Flowering Rush, Hydrilla, Brazilian Egeria, Purple Loosestrife, Eurasian Watermilfoil, Curly-Leaf Pondweed, Spiny Water Flea, Zebra Mussel, Asian Carp, Round Goby, Chestnut Lamprey. [extension….linois.edu]

    Invasive Carp Threat in Illinois River System

    The state remains a frontline defender against invasive carp entering the Great Lakes.
    A 2025 field study highlights ongoing monitoring of exploding Silver Carp populations and measures to prevent movement toward Lake Michigan. [chicago.suntimes.com]

    Statewide Coordination

    Illinois’ Wildlife Action Plan includes a comprehensive Invasive Species Campaign focusing on prevention, early detection, and interagency collaboration. [dnr.illinois.gov]

    Why AIS Management Matters for Wisconsin Lakes

    Wisconsin’s lake health—water clarity, habitat structure, fishing quality, and recreational value—depends on persistent vigilance. Neighboring states face similar threats, and regional collaboration has never been more important.

    How You Can Help

    • Inspect boats and gear: Follow Wisconsin’s “No Transport” law to remove all plants, animals, and mud.
    • Report sightings immediately: Wisconsin DNR’s reporting portal enables quick verification.
    • Volunteer for monitoring: Local lake associations and Water Action Volunteers welcome community scientists.
    • Stay informed: Many AIS now spread through gear, aquarium releases, and hitchhiking in bait and plant fragments.

    Conclusion

    Aquatic invasive species remain a dynamic challenge across the Upper Midwest, with Wisconsin at the center of coordinated regional efforts. By understanding which species pose the greatest risk—and by learning from neighboring states’ battles—we can better protect the lakes we love.

    If you’d like, I can turn this into a formatted PDF, add images, or adapt it for social media or newsletter distribution.

    1. Wake-Enhanced Boating: Balancing Recreation and Lake Health

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    Wake-Enhanced Boating: Understanding the Science Behind the Waves

    Wake boats have surged in popularity across Wisconsin’s lakes, offering thrilling recreation for wakeboarding and surfing enthusiasts. However, these vessels are engineered to create large, powerful wakes—waves that can be several times larger than those produced by traditional boats. While fun for riders, these wakes introduce significant physical and ecological changes to lake systems that deserve careful consideration.

    The Physics of Wake Formation

    Wake boats use ballast tanks to increase displacement, causing the hull to sit deeper in the water. This design amplifies wave height and energy. Unlike normal boat wakes, which dissipate quickly, wake-enhanced waves carry more energy farther from the source. Studies show that these wakes can persist for hundreds of feet, impacting areas well beyond the immediate boating zone. The energy transfer from these waves accelerates shoreline erosion and resuspends sediments, which can cloud water and release nutrients trapped in lake bottoms.

    Impacts on Shoreline Stability

    Shorelines are dynamic interfaces where vegetation stabilizes soils and filters runoff. When large wakes repeatedly strike these zones, root systems weaken, and soil particles wash away. This erosion not only alters property lines but also increases sediment loading into the lake, reducing water clarity and promoting algal growth. Over time, the loss of natural buffers can lead to a cycle of degradation that is costly to reverse.

    Effects on Aquatic Habitat

    Wake energy doesn’t stop at the shoreline—it penetrates the water column. In shallow areas, turbulence uproots aquatic plants that provide habitat for fish and invertebrates. These plants also play a critical role in oxygen production and nutrient cycling. Disruption of these communities can cascade through the food web, reducing biodiversity and altering fish spawning success. Additionally, suspended sediments can smother benthic organisms and degrade spawning beds.

    Water Quality Concerns

    Sediment resuspension caused by wake turbulence can release phosphorus and other nutrients from lake bottoms. This internal loading can fuel harmful algal blooms, especially in lakes already stressed by external nutrient inputs. Increased turbidity also reduces light penetration, limiting photosynthesis for submerged vegetation and further destabilizing the ecosystem.

    Depth and Distance Matter

    Research suggests that operating wake boats in water deeper than 30 feet and at least 700 feet from shore significantly reduces ecological impacts. In deeper zones, wave energy dissipates before reaching sensitive habitats, and sediment disturbance is minimized. These guidelines are based on hydrodynamic modeling and field observations, emphasizing that location and depth are critical factors in mitigating harm.

    Toward Science-Based Management

    Lake associations and property owners can play a proactive role by promoting best practices grounded in science. Educational campaigns, voluntary compliance zones, and collaboration with local enforcement can help balance recreation with conservation. Ultimately, understanding the physics and ecology behind wake-enhanced boating empowers communities to make informed decisions that protect Wisconsin’s treasured lakes for generations to come.

    Exploring Hot Lake Topics for 2026

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    Over the course of the next year, Wisconsin Lakes will look to explore our changing world of lakes. Here are five high-impact blog topics that we look to explore here at WisconsinLakes.net that are relevant to lake associations, property owners, and districts:

    1. Wake-Enhanced Boating: Balancing Recreation and Lake Health

    • Why it matters: Wake boats and ballast systems are a growing concern in Wisconsin and lake communities in general. They can damage shorelines, uproot aquatic plants, and disturb fish habitats.
    • Goal: Work to explain the ecological impacts, summarize proposed statewide regulations (e.g., distance from shore, recommended depth), and offer practical tips for lake associations to manage wake sports locally.

    2. Combatting Aquatic Invasive Species (AIS): Prevention and Rapid Response

    • Why it matters: AIS like Eurasian watermilfoil and zebra mussels threaten biodiversity and property values. Starry Stonewart is a newly identified threat in WI.
    • Goal: Share best practices for prevention (boat cleaning, ballast tank decontamination), highlight new DNR initiatives, and showcase success stories from Wisconsin lake districts.

    3. Climate Change and Wisconsin Lakes: What Local Data Shows

    • Why it matters: Longer ice-free seasons, warmer water, and nutrient loading are changing lake dynamics. As previously touched upon we will reopen this topic based on emerging data.
    • Goal: Use Citizen Lake Monitoring Network data to illustrate trends in water clarity, temperature, and algal blooms. Offer adaptive management strategies for lake associations to consider.

    4. Shoreline Management and Erosion Control for Property Owners

    • Why it matters: Poor shoreline practices accelerate erosion, degrade water quality, and reduce property value.
    • Goal: Provide actionable guidance on buffer zones, native plantings, and ordinances. Include links to model regulations and funding opportunities for restoration projects through possible cost share.

    5. Forming and Strengthening Lake Associations: Governance and Funding

    • Why it matters: Strong associations are key to sustainable lake management and property value protection.
    • Goal: Outline steps to create or revitalize a lake association, explain statutory powers under Wisconsin Chapter 33, and share tips for securing grants and building community engagement.

    Climate Change and Your Lake

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    The change appears to be slow. In fact, it may not even appear to be noticeable. What are even the signs? Wisconsin and the Midwest are home to a wide variety of lakes, all of which may be impacted in different ways. In addition, management of lake issues has been an evolving practice since its inception, so adding contingency to a wrinkle for an imperfect science only makes things more complicated for stakeholders with controlled budgets. Wisconsinlakes.net has not yet seen a good guide or resource page that provides any real guidance surrounding the issue of climate change, most likely because to the naked eye it may appear to be normal issues continuing to manifest themselves, albeit in an accelerated or different manner. We hope the information within this posting proves beneficial to some. None of this is backed by research or academic sourcing. It is observational and is not universally applicable.

    To continue this in this post discussion, it must be understood that climate change is a real thing, not a made up concept from 1987. Most have accepted this by now. In fact climate change is being referred to as “climate shift” by many in the sense that climate is not simply changing but, but causing a physical shift of range of changes. Regardless of how you wish to catalog these changes internally, they are in fact a real thing and will likely require solutions based on adaptability and proactive maintenance rather than a fixed endgame solution.

    While coarse policy begins to take shape both nationally and globally, communities are faced with real world issues that impact people at the local scale, both economically and from a health and safety perspective. There are endless miles of utility infrastructure beneath the grounds surface, all of which are at some degree of risk. There are no fast and ready rules to apply because each of these communities geographical space is unique. Some face coastal concerns, some flooding, and yet some seismic. The geographical space and unique weather patterns all require custom approaches. Even more so with lakes. Lake types can differ greatly simply by being a few miles apart and will therefore act differently due to precipitation, landscape positions, watershed size, urban influence, temperature flux, and other factors both known and unknown.

    The term resiliency is often used to describe the process of making something able to withstand or adapt to change. There is also a general school of thought that believes that natural systems are generally more resilient than manufactured systems. Often potentially overlooked in this equation is general systems maintenance. Do systems lack resilience or do they generally lack maintenance? These can be difficult questions to answer. Even more importantly is the need to consider the tracking of assets for those same maintenance reasons.

    So how does all of this factor into a discussion about our lakes, climate change, and the quest for resiliency? Below is a list of potential considerations for your lake that can be potentially influenced by climate change:

    Shorelines: Several of the topics below have a degree of interplay, that is they do not operate independent of each other but each may influence each other. Shorelines can be impacted by water level and system volume, among other things. Vegetative systems that make up shorelines adapt to water levels but take decades to adjust since ecological systems react over time. Waves and ice add a dynamic, but these are still natural occurrences, whereas wakes are not.

    As climate reduces months of ice cover in Wisconsin, that is traded for more precipitation as rainfall. Additional months of rainfall throughout the Midwest can result in higher groundwater levels or longer periods of drawdown at dams and outlet structures. Elongated periods of high water put natural systems at risk as they can be exposed to extended periods of inundation, wave impact and even record high wake impacts. Several river systems in WI and throughout the midwest have shown signs of higher than average baseflow. Higher baseflow results in necessary shoreline adjustment, albeit incremental over time.

    Water elevation will be discussed further below, but sustained high water exposes shoreline not traditionally adapted to water inundation. Saturated soils may leach fines (smaller soil particles) and girdle vegetation roots, increasing the mortality of plants and increasing erosion or lateral loss of land.

    Reinforced shorelines are not absolute solutions. Man-made systems can be compromised by repeated overtopping, toe scour, or improper design. Research also suggests that hard armor shoreline reflects wave activity along adjacent unprotected shorelines and can have ecological impacts. These effects can have cumulative effects in urbanizing lake environment. Shoreline solutions will need to flexible rather than simplistic. Good solutions typically suggest bio-engineered shores capable of withstanding wave and wake punishment, but also regrowth of vegetation when possible.

    Sediment: 10/7/2023

    Water Level: TBA

    System Volume: TBA

    Infrastructure: TBA

    Lake Ecosystem: TBA

    Nutrients: TBA

    Loving our Lakes to Death

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    I’ve spent a lot of time this last year visiting lakes with similar issues. The issue is not unique to lakes but remains an ongoing concern with any waterbody with humanly influenced frontage. The desire to get closer to the water and the serenity of its influence is having a directly negative influence. This influence has led to a number of compounding side effects resulting in habitat loss, sedimentation, unnatural nutrient introduction, flooding, and although not nearly as well documented, property damage.

    Shoreline encroachment is a process in which man moves closer to the water. The reason for doing so may very ever so slightly; in some instances water is the obstacle where in other cases it is the objective.