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A Concern for all Land Conservation Agencies and Organizations: The habitat destruction wrought by invasive plant species is of concern to all conservation agencies and organizations-- particularly those that own and manage open space lands. Audubon Connecticut maintains and manages 15 sanctuaries totaling over 4,500 acres within the state, and effective management of the lands under our care is of the utmost importance.

Current Situation: Both land-based and aquatic invasive plants are pervasive throughout the state and can cause serious problems. Among the invasive plants that occur on Audubon sanctuaries are Asiatic bittersweet, autumn olive, barberry, European privet, garlic mustard, honeysuckle, Japanese Knotweed, mile-a-minute weed, multi-flora rose, Norway maple, the common reed phragmites, purple loosestrife and Russian olive, and winged euonymous.

In 1997, an invasive planted called "mile-a-minute weed" invaded one our Audubon Sanctuaries in Greenwich. This annual plant has proven to be so aggressive that it has completely changed the ecology of more than 10 acres of the 80-acre Gimbel Sanctuary. The plant forms tangled mats that climb over other plants and trees, killing the vegetation beneath. The hardiest native plants and even some especially aggressive exotic plants like honeysuckle and bittersweet are out-competed by mile-a-minute weed. As far as we know, this was the first time that this particular invasive plant was detected in Connecticut.

Living up to its name, this weed quickly took over, pushing aside the native vegetation and creating a monoculture--a poor substitute for the diverse native vegetation it replaced. Sanctuary managers expended significant efforts over the summer and fall each year since the plant was discovered in an attempt to control and remove the weed. Several thousand man-hours by volunteers and paid staff have been spent pulling, spraying and cutting the plant, and several thousand dollars are expended each year on control methods. Despite these efforts, the plant has spread onto neighboring properties, and municipal and state conservation officials have expressed concern about its advance and the need for control. This year, for the first time, Audubon Connecticut has decided to hire a full-time staff member during the spring through fall for the sole purpose of combating this noxious weed. Since this is an annual plant that widely sows its seeds, the expectation is that the weed will return each spring, and continue spreading throughout the sanctuary, into neighboring properties and eventually throughout Greenwich and into neighboring towns in Fairfield County. It is naturalized in Maryland, New York and Pennsylvania, and can potentially spread throughout Connecticut. This single plant species can cause significant economic losses related to its control in residential and urban landscapes, as well as cause substantial damage to the quality and diversity of habitats.

Why are invasive plants a problem? Invasive plants produce severe, often irreversible impacts on agriculture, recreation, and our natural resources. Invasive plants threaten bio-diversity, habitat quality, and ecosystem function. These plants can also seriously damage landscaping that has been installed around homes and businesses. Invasive species are the second only to development in the destructive threat they pose to habitat for native plants and animals. Forty-two percent (42%) of threatened and endangered species in the U.S. have suffered declines due to competition from nonnative invaders. The economic costs incurred because of nonnative species invasions reach billions of dollars in this country each year.

What needs to be done? The issue of invasive plants needs urgent attention from the Connecticut General Assembly and the Department of Environmental Protection. It is essential that we manage the state's landscapes to maintain healthy and diverse ecosystems that support a thriving variety of interacting plants and animals--as nature intended--instead of allowing them to be dominated by non-native species. Although the newly created Invasive Plants Council has made great progress reviewing and agreeing on a list of plants that are considered invasive or potentially invasive, the Council has yet to issue a list of plant recommended for banning.

Reducing or Eliminating Invasive Plants: Complete removal of invasive plants may be feasible early in an invasion or in a restricted area, but more often control or containment is the only practical way to limit ecological or economic damage, especially for species that have already invaded large areas. Control methods can include the following or a combination of all four:

• Chemical control (using pesticides) can be effectively used to kill invasive species, but it can be problematic due to impacts on non-target organisms (including humans), the development of resistance, and expense.
• Mechanical control (physically removing the invasive species) is often successful, but can be expensive and labor intensive.
• Biological control (introducing a natural enemy-predator, parasite, or disease-often from the pest's native range) can be an environmentally sound way to control invasive species with minimal expense, but some control agents do not survive and others attack non-target organisms, or become invasive themselves.
• Ecological control (manipulating environmental factors such as fire and water flow) can provide native species an edge in competing with invasive species.

Restoration: Once the invasive species have been controlled or eliminated, restoration may be needed to restore lost components or functions to degraded areas. Restoring native communities is an important step to minimize the chances an area will be reinvaded.

The most powerful and cost-effective method for reducing or eliminating invasive plants, however, is prevention - - and a ban is the first step toward educating the nursery industry and others, along with private homeowners about the threat posed by invasive plants.

Prevention: The best way to limit impacts of nonnative species is to prevent them from invading and becoming established in a new area. Banning the sale and importation of plants known to be invasive into the state would be the most effective action. Because invasive species do not recognize property boundaries, successfully controlling invasions requires partnerships between public and private landowners, government, industry, academia, and non-governmental organizations. Education will be a key factor in this effort, but a ban is a critical first step.

Where to go for more information:

A list of invasive plants--plants that you will surely want to avoid in your own gardens--is available either by calling the Connecticut Geological and Natural History Survey at (860) 424-3585, or on-line at: http://www.hort.uconn.edu/cipwg/ind_spec/ind_spec.html

The Nature Conservancy’s information page on Invasive Species: http://www.natureserve.org/conservation/invasivespecies.jsp

National Invasive Species Council — The U.S. federal government's official coordinating body on invasive species issues. http://invasivespecies.gov

Westbrooks, Randy G., Invasive plants: changing the landscape of America: fact book. Washington, D.C.: Federal Interagency Committee for the Management of Noxious and Exotic Weeds, 1998. https://www.denix.osd.mil/denix/Public/ES-programs/Conservation/Invasive/intro.html

Audubon Connecticut, an operating unit of the National Audubon Society with
over 13,000 members in the state, works to protect birds, other wildlife
and their habitats through education, research, conservation and legislative advocacy.