Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

Men in boat netting jumping fish © U.S. Fish and Wildlife Service

Asian carp are a serious concern because they compete with native fish and can injure boaters when they jump out of the water.
© U.S. Fish & Wildlife Service

June 2012

Slow the spread by hand and tread

June is Invasive Species Awareness Month in Wisconsin.

Cary Kostka

Watch us on YouTube Watch Saving Shorelines from Invasive Plants video

From Eurasian watermilfoil and Asian carp, to emerald ash borer and gypsy moth, the state is under attack from all directions. These invasive species cause serious damage not only to the ecology but to environmentally dependent industries such as timber, fishing and tourism.

Those who live, work or play in Wisconsin can, and should, play a vital role in slowing, stopping and preventing invasive species in this state.

As a response to the increase of invasive species in Wisconsin, the Department of Natural Resources in 2009 created Chapter NR40 in the administrative rules to teach people how to identify invasive species as well as ways to prevent their spread. The rule allows the department to take quicker action against a potential or known invader, as well as to ensure that any actions are consistent.

What are invasive species?

Invasive species are non-native species that are introduced, often by human activity, into an area and cause damage to that area’s ecosystems.

But not all introduced species evolve into ecosystem destructors. In fact, in most cases the introduced species has little, if any, impact on its introduced area and, in some cases, non-native species actually benefit some ecosystems.

It seems that almost everyone in a typical neighborhood has Japanese somethingor- others, or a Colorado pine of some sort in their yards, but we do not see these taking over the Wisconsin landscape. Nonnative plants cannot be all that bad then, right? Wrong.

Introducing non-native species can have unpredictable results on the surrounding ecology. There are many factors involved for a non-native species to move from being just an introduced species to becoming an invasive species.

Non-natives tend to lack natural predators in a new area. How do these species fair in Wisconsin winters? Can they thrive in the sandy soil of northern Wisconsin, or in the clay-based soils of southern Wisconsin? Will local bees pollinate introduced flowering plants, and how do the seeds and seedlings germinate?

These are just a few of the questions that factor into an introduced species’ ability to become invasive.

What can we do?

Landowners, those who lease land, or those who work or play on Wisconsin lands can help the Department of Natural Resources and other agencies take a stand against the spread of invasive species.

Be on the watch. According to the Department of Natural Resources there are over 70 NR40-regulated plants currently on the loose in the state, not to mention a large number of insects and animals. A full list of these can be found at the DNR’s website. Visit Wisconsin Department of Natural Resources and search “invasive species.”

Preventative steps and invasive species identification are the first and perhaps most important steps in attacking invasive species in Wisconsin. Your ability to identify and properly report an invader is vital to tracking and removing invasives. Reporting the invader(s) allows the Department of Natural Resources to track where an invasive species may be moving, as well as to determine a best course of action to eradicate the invader.

According to the Department of Natural Resources there are five best practices for landowners and land users to be aware of: prevention, early detection and rapid response, control, monitoring and restoration.


Prevention is the safest and easiest way to ensure that an area remains invasive free. Here are some tips:

  • After completing outdoor activities, be sure to inspect your clothing and footwear for any plant matter that may be tracked or fall off of your person outside of the area in which you were active.
  • Consider bringing two sets of footwear to an area you will be walking through. That way, you can simply change shoes when moving into another area.
  • Avoid traveling through areas where invaders are known to be.
  • Clean all equipment used during your outdoors activity, including recreational equipment (such as bicycles, ATVs or rollerblades) and lawn and gardening equipment (such as lawn mowers, rototillers and chainsaws).
  • When gardening or landscaping, do not plant seeds, seedlings or any other plants that are not native to the area.
  • Properly dispose of all landscaping materials that you will not be composting.
  • Minimize the amount of native species you remove from your property as well as the amount of soil you disrupt. Disrupted soil makes it easier for seeds that make it to the ground to germinate.
  • Never transport firewood beyond 25 miles of where you found or bought it.

Early detection and rapid response

Early detection means a rapid response can be mounted, saving both you and the Department of Natural Resources many hours of labor and preventing undue ecological and financial strains.

Familiarize yourself with the invasive species already present in the state. Also, it is important to remain up-to-date on newly identified invasive species by frequently checking the department’s invasive species Web page, especially in the late spring and early summer months, as this is the time most invasive plants begin to flower or seed. If you come across an invader, report your sighting by calling your nearest DNR office or by following the steps on their website.

This way, the Department of Natural Resources will be able to formulate the best course of action not only for your property but for any of the surrounding properties, whether they are public or private.

Containment and removal

So you have found an invader on your land. Now what? In most cases you will begin by using a combined prevention and control method called integrated pest management (IPM). This means using destructive methods on the invaders while performing preventative measures in the affected area and surrounding areas.

Completely removing the invader is possible, especially if the invader is discovered early in its establishment. However, once the invader is widely established the best course of action is usually to control the pest in a way that reduces its density to the point of becoming balanced with the surrounding native species.

Photo of garlic mustard leaves. © U.S. Fish and Wildlife Service
Garlic mustard reaches 12 to 48 inches and has a distinctive odor of onion or garlic when crushed.
© U.S. Fish & Wildlife Service

There are several methods to contain or remove invading species.

First on the to-do list is to slow and prevent further spread of the invader. How to do this depends on the nature of the invader (plant, tree, insect, mammal, etc.).

For plants, cut or mow the area frequently during the height of the invaders’ growing season while making sure you fully clean any equipment used before using it in another area. Hand pulling an invasive plant can be effective, but when doing so make sure you are getting the entire root system. Smothering plants is especially effective against low-lying plants and should be done using mulch or other environmental landscaping plastic for at least one full growing season.

If available and allowed by local ordinances, you can use a grazing animal to eat the invader. An appropriate herbicide can lend a helping hand for the especially tough invader that does not appear fazed by any of the previously mentioned methods.

For trees, consider girdling, which is the process of removing bark in a ring around the tree and then applying herbicide to the removed area. A controlled burn is especially effective, but is probably best left to an expert.

Controlling invasive insects mainly requires the use of pesticides or unleashing native predators.

Trapping may be in order for mammals or reptiles, but this technique should be handled by a professional so the effects have a minimal impact on native species.

These are only some examples of the many methods used to contain or remove an invasive species. A complete list of the methods available as well as herbicide recommendations and species timing cycles may be found on the DNR website.

One last thing to remember is that any invasive plants or trees that are removed should be disposed of in a landfill. Thanks to the DNR’s enforcement abilities, local landfills must accept these plants. Place them in clear plastic bags, label them “invasive plants; approved by WI DNR for landfilling,” and dispose of them according to your local landfill regulations.


As your containment and removal activities come to a close, having a good monitoring strategy in place can help reduce the likelihood of an invasive’s return. Regularly check previously infected areas and the surrounding areas early in the spring through the end of the invader’s growing season (or mating season for non-plants). Check that no new invaders have taken up residence.


Restoring invader-affected areas on your property is an important step as it restores vitality and balance to your property’s ecosystem. Following the DNR best practice guidelines also helps prevent re-establishment. The easiest and most effective method is to plant (or release in the case of non-plant invasions) as many species native to your area as you can while maintaining a competitive balance among them.

A team effort

Those of us who live, work and play in Wisconsin serve an important role in the battle against invasive species. Whether we contribute by securing our own properties, volunteering to pull garlic mustard plants at one of our great state parks or by alerting local authorities to a newly found patch of wild parsnip, we can all work together and turn the invaders back.

Cary Kostka has participated in various invasive plant cleanup programs in southeastern Wisconsin.

The mighty phragmites, a bio-bully of the bay

It’s Wisconsin’s largest attempt at phragmites control using an herbicide. In fact, in one year, about 3,400 acres of the invasive lakeshore weed were sprayed. This targeted effort was in partnership with over 1,530 riparian landowners who wanted to restore the shoreline and regain their view of Lake Michigan from a bio-bully.

Phragmites australis subsp. australis came to Wisconsin shores by hitching a ride in large ballast tanks of cargo ships. Here, it found prime real estate on the mucky, moist soil of exposed lakebed and coastal wetlands.

Phragmites (pronounced phrag-my-teez) causes significant cascading ecosystem disruptions such as alterations to food webs and nutrient dynamics, biodiversity and ecosystem stability. It competes with native species for limited resources including habitat, food and light.

Phragmites is highly aggressive and can grow up to 30 feet tall with sturdy, Photo of men standing in front of phragmites © Heidi Springbornrobust stalks and thick, feathery plumes that block lake views. Once established, it shades out native vegetation and makes coastal shorelines and wetlands unfit for wildlife. According to wetland experts, Wisconsin has already lost 70 percent of the original wetlands along Lake Michigan.

Phragmites also has overtaken public lands and invaded backyards of over 1,500 Green Bay West Shores and Lake Michigan shoreline owners. For the past several years, shoreline owners have tried to control infestations and some have spent thousands of dollars in the fight. Phragmites can be found in nearly every state. Globally, there is only one place it hasn’t been found…yet. Antarctica!

The Department of Natural Resources was recently awarded $805,600 from the Environmental Protection Agency Great Lakes Restoration Initiative for a large-scale effort to reduce invasive phragmites and lyme grass from 3,600 acres of coastal wetlands along 118 miles of Lake Michigan shoreline in Brown, Door, Oconto, Manitowoc, Marinette and Sheboygan counties.

Target areas during the three-year grant term include 25 state natural areas, six state parks, three state wildlife areas, Point Beach State Forest and 1,530 private lands adjacent to the exposed bed of Lake Michigan.

During the summer of 2011, department staff treated 290 acres in Door, Manitowoc and Sheboygan counties, and two ecological restoration firms treated another 111 acres in Marinette, Oconto, Manitowoc and Door counties using several control methods including boom-mounted, ATV or boat spray units; backpack sprayers; and the bundle, cut and spray method in sensitive areas.

Three thousand acres along the Green Bay West Shores and Gardner Swamp in Door County were sprayed by helicopter because phragmites is tall, dense and occupies areas that aren’t accessible from the ground. Conditions are wet, and many times it’s difficult to get vehicles in or to work with backpack sprayers. A helicopter can get close to the vegetation by flying low and slow for better herbicide application. The helicopter is maneuverable and equipped with a GIScontrolled, boom-mounted low pressure sprayer. Acres treated by county, include:

  • Marinette: 735 acres, 13 miles of shoreline
  • Oconto: 1,300 acres, 30 miles of shoreline
  • Brown: 910 acres, 10 miles of shoreline
  • Door: 50 acres (Gardner Swamp State Natural Area)

The herbicide Imazapyr (brand name Arsenal®) is absorbed by phragmites and travels to the bulk of the plant and the roots where it does its damage. Sprayed plants don’t die right away, so some vegetative material is visible for a while. This year, treated areas will be monitored for the success of herbicide application and follow-up spot treatments will take place. Some areas also were mowed where we couldn’t definitively identify the plant.

This project is a first step. More work needs to be done. There are many challenges associated with this project. Among them, Lake Michigan water levels are at historic lows and phragmites has quickly filled in.

Phragmites is a monoculture: a biological desert of predominantly one species. Phragmites knows no boundaries and can be found on public and private land and in the riparian area (dry land on exposed bed). The department needs permission to access private areas for treatment. Many people have been involved and coordination is critical.

Another challenge is that funding is not available for follow-up mowing of all private riparian areas and this application is not a cure-all. Some phragmites will still exist when the grant expires in December 2013 and it will take proactive management to keep phragmites under control.

The next steps include continued aerial and ground spraying this year and in 2013 if funded. Some areas missed in 2011 will get initial treatment this year. Ideally, all acres will receive one year of follow-up and most will receive two years.

We also will mail information to landowners to let them know what to expect and will continue to teach the public about phragmites identification and control techniques. A project coordinator was hired for all associated field activities and educational opportunities. The department also hosts a phragmites hotline so that people can call in and get day-to-day news of shoreline spraying August through October. The hotline number is (920) 662-5139 during spraying.

For more information on the project or for any phragmites-related questions, please call (920) 662-5447 or email Heidi Springborn

By Heidi Springborn, conservation biologist with DNR's Bureau of Endangered Resources.