Photo of a volunteer cutting brush © Joe Henry

A work party to cut down invasive tree species
© Joe Henry

April 2010

A strategic plan to manage invasives

Wisconsin has a new tool to curb invasive species.

Courtney A. LeClair

In this story: Reporting invasive species; Non-native fish are a special case; Best management practices; A garden where a problem was nipped in the bud; Invasive species regulated by NR40

Some of you may be able to give an example of an invasive species, but can you tell me what they are? In Wisconsin, they are defined as non-native species whose introduction causes or is likely to cause economic or environmental harm or might harm human health. Invasive species disrupt and intrude on many aspects of our lives. They can crowd out or kill native plants and animals in waters,woods, prairies, parks, gardens and back yards. They can contaminate agricultural crops and, if ingested, may be toxic to livestock, pets and humans. Several invasive species alter soil chemistry and slow plant growth. As plant composition is changed, populations of animals that rely on a plant species for food, cover or nesting sites are displaced. Invasive insects, such as emerald ash borer and Asian long-horned beetle, can weaken or kill trees through girdling and burrowing.

In addition, most people who enjoy the outdoors view invasive species as annoyances that make it more difficult to reach or enjoy the places they hold dear. In the absence of natural predators or controls, invasives can overrun and blanket native species. They destroy parts of what make places special by altering the environment.

Outbreaks of invasive species are becoming more prevalent in news reports when they are first discovered or when they make the jump to a new area. Policy debates about them have recently gone all the way to the Supreme Court regarding closing locks in Chicago to prevent the spread of Asian carp into Lake Michigan. So many different non-native species have been documented on land and in water that you might think there is no hope that invasives can be contained or controlled, but that is not the case for all species. Resource managers have made great efforts in recent years in learning the most effective ways to control some of these species. Preventing new species from getting established and slowing their spread are critical. Wisconsin now has a new tool to help do just that.

Reporting invasive species: If you suspect you have found a prohibited species, please contact the DNR invasive species team promptly. Send an e-mail: Invasive.Species@Wisconsin.gov or call 608-267-5066. Explain where you found the plant or animal, the population size, when you found it, and who owns the land (federal, state, other public land or private parcel), and tell us how we can contact you. It is also very helpful if you send pictures or a specimen of the species. With this information, the identification of the species can be verified and mapped.

After five years of hard work, Wisconsin's Invasive Species Identification, Classification and Control Rule (NR 40) became effective September 1, 2009. This rule was developed by a team of DNR staff specialists and the Wisconsin Council on Invasive Species working with an advisory group. They assessed species for possible listing in the rule and provided extensive opportunities for public comment, after which many revisions were made. This rule identified over 120 species as being invasive and grouped them as plants, fish and crayfish, aquatic invertebrates other than crayfish, terrestrial invertebrates and plant disease causing microorganisms, terrestrial and aquatic vertebrates other than fish, algae and cyanobacteria. Each organism was classified as either prohibited or restricted warranting different actions.

Prohibited species are those that are not yet known to be established in Wisconsin or are present in small infestations and, if reported, may warrant control efforts. These species would likely cause serious problems if left unchecked. As a prevention strategy, no person may transport, possess, transfer or introduce any of these species without a permit. When a prohibited species is found, the goal is generally to eradicate it if feasible or at least prevent it from spreading. Wisconsin DNR staff will work with the landowner to determine the best method of control and where possible, will seek to find funding, equipment, volunteers or other assistance to help with the control. Control of most invasive species takes several years, so monitoring the site and nearby areas is critical.

Restricted species are usually fairly widespread throughout a region or are found statewide and the chance of statewide eradication is low. Many of these species have already caused substantial economic and environmental damage. Some also harm human health. No person may transport, transfer or introduce any of these species without a permit with the exception of fish and crayfish. If a restricted species is present on your property, control is encouraged but is not required.

Some plant species are listed in both categories – restricted where the species is already established and prohibited in large portions of the state where it has not been found.

See Chapter NR 40, for more information.

Non-native fish are a special case

Unlike the other species detailed in the rule, all non-native fish and crayfish are regulated. Below are guidelines on what is considered prohibited and restricted.

All non-native fish and crayfish are prohibited unless they are: a) considered to be established species and are listed specifically as restricted. b) part of an established aquaculture industry. c) non-native viable fish species legally sold in the aquarium trade. d) considered to be a nonviable fish species. (See #3)
All of these species listed a-d above are classified as restricted.
Fish and crayfish are "viable" if eggs, fry, and adults can survive in water temperatures below 38°C (100.4°F) and can survive in fresh water.

Restricted fish and crayfish cannot be transported, possessed, transferred or introduced without a permit. Exceptions include Koi carp and goldfish that are not used for bait or not introduced into public waters. Koi and goldfish may only be introduced into artificial ponds that are entirely confined and retained on private property where there is no chance that the fish might escape (no flooding potential and no connection to other water systems).

Rusty crayfish, non-native viable fish species, and nonviable fish in the aquarium trade can be possessed or transported without a permit if kept in a safe facility like an aquarium or container that does not empty into a water body or water system with any chance of escape. They cannot be kept in an open pond. In addition, non-native fish species used for aquaculture may be transported and possessed in a safe facility or transferred without a permit. None of these exceptions allows introducing any non-native fish or crayfish species into water systems.

Along with this new invasive species rule, the state legislature recently passed a bill called Act 55 that helps to fill in the gaps in existing invasive species laws that the Department of Natural Resources did not have authority to cover. One such change exempts prohibited and restricted species from yard waste as many of these plants have seeds that can survive in municipal compost piles. These plants can be landfilled as long as they are not mingled with other yard waste.

Act 55 also expanded existing laws and NR 40 regarding transportation of aquatic plants and animals.

Together, Act 55 and NR 40 also set preventive measures in place making it illegal to transport or launch vehicles, watercraft or any other equipment (except weed harvesters) that have aquatic plants or animals attached. Conservation wardens and other law enforcement officials can order the removal of aquatic plants and/or animals and can issue citations for violations.

Some people wonder why the regulations cover invasive species that seem to be "everywhere." Even widespread species have not yet spread to all parts of the state. Keeping these species contained and minimizing their spread is the intent of the restricted category. In addition, many species have not been found in Wisconsin and others only occur in smaller local pockets. These are the species where early detection and control can make a big difference. Your actions may prevent a species from invading new lakes, prairies, fields or forests.

So what is going to be different now that rules to contain invasive species are in place? For one thing, education is critical. In order for the public to watch for and report these species, they need help to identify the invasive species and to learn how to report those sightings. The more people who are trained to recognize these species, the more likely that control plans will be developed and work crews organized to contain, control or eradicate them. Training sessions are being held throughout the state for people who spend a lot of time outdoors such as Master Gardeners, naturalists, landowners, outdoor enthusiasts, utility and highway workers who maintain rights-of-way and land managers who oversee parks, trails, and forests.

Trail and park users will see some changes as well. You may notice signs, posters or other educational material at trail heads warning of common invasive species found along the trails. Outdoor enthusiasts can play an important role in preventing the spread of invasive species by staying out of infested areas and reporting prohibited species they see. One important step everyone can take is disposing of hitchhikers you may have picked up along the way – seeds can stick to your clothing or plant fragments and small organisms can get caught in the treads of your bike tires or in the soles of your shoes. Some trails may provide boot brushes to clean off your footwear before moving on, but you could also carry one with you.

A good general rule is to leave plants and animals where you find them to lessen the risk of transporting an invasive species to new places.

For more information, see Invasive Species.

Courtney A. LeClair is an AmeriCorps member who is funded through the Natural Resources Foundation of Wisconsin and is working on early detection of invasive plants with DNR's Bureau of Endangered Resources.

Best management practices: Guidance for landowners, land managers and others who spend timein the outdoors

Under the direction of the Wisconsin Council on Forestry, a diverse group of stakeholders recently developed voluntary guidelines to prevent the spread of invasives in forests, recreational areas, transportation and utility rights-of-way and urban areas.

General recommendations to limit the potential of introducing and spreading invasive species include:

Avoid traveling through or working in small isolated populations of invasive plants.
Minimize soil disturbance. Many invasive species gain a competitive edge when the ground is disturbed and cover plants are removed.
Know what you are planting so you don't introduce an invasive plant.
Clean equipment, shoes and clothing when leaving infested areas.
Post signs and other information to inform and educate people using the parcel or corridor about invasive species that are commonly found there.
Train staff, contractors and volunteers to identify invasive species that may be found in an area.

Detailed manuals are available that provide more specific recommendations to slow the spread of invasive species. You can find the Best Management Practices manuals on the web at Wisconsin Council on Forestry.

A garden where a problem was nipped in the bud

When meandering through the University of Wisconsin-Madison Botanical Gardens last summer after a Badger football game, a visitor saw a beautiful water plant growing in the small ponds. Its yellow flowers poked above a mat of green leaves floating on the water's surface. The visitor recognized the plant as yellow floating heart (Nymphoides peltata) and knew it had just been listed as a prohibited invasive species under the new invasive species rule (NR 40). The visitor contacted the Department of Natural Resources and Susan Graham, DNR's Water Resources Management Specialist for the South Central Region, who contacted the garden director, Dr. Mo Fayyez. He had noticed this aggressive plant as well and had attempted to control it the previous year.

After further examination, other plants in the garden were discovered that were listed under NR 40. Dr. Fayyez was notified and immediately the plants were removed. Special care was taken when removing yellow floating heart and draining the ponds to ensure that neither seeds nor any root fragments travelled into the storm sewer. The sewer the ponds drain into connects to Lake Monona and managers wanted to prevent any infestation in the Madison lakes.

Once identified, control of this prohibited species was dealt with swiftly, with good cooperation and at minimal cost. The garden director acted quickly to remedy the situation and is working in coordination with DNR staff to develop a long term plan for the garden ponds to contain the problem plants and monitor the gardens to prevent future infestations.

It is important to remember that results are rarely immediate; they take a plan, time, and persistence (several years) in order to be effective.