Illinois residents urged to help combat invasive species

By on June 2, 2012

SPRINGFIELD—Invasive plant and animal species are threatening Illinois’ agricultural and natural lands and waterways, consequently posing a threat to the state’s economy. Governor Pat Quinn has issued a proclamation declaring May to be “Invasive Species Awareness Month” to encourage Illinois residents to learn about ways in which they can help combat the introduction and spread of invasive plants and animals in the state.

The Illinois Department of Natural Resources (IDNR) Division of Natural Heritage reports that animals and plants not native to Illinois at the time of European settlement are considered exotic species. Many species of exotic plants are harmless and very useful in windbreaks, landscaping, and in preventing erosion. However, some exotic species do have the potential to invade natural communities and displace highly desirable native plants. Such plants are invasive species. Some invading plants have become so well established in many areas throughout Illinois that they may be thought of as native species.

“Employees of local, county, state and federal gencies and hundreds of volunteers throughout Illinois spend millions of dollars and thousands of hours every year in attempts to eradicate, manage or control invasive plants and animals on the ground and in our waterways. The Governor and conservation agencies and organizations are working to make all Illinoisans aware of the impacts of invasive species to Illinois’ diverse landscape—and the environmental and economic costs we face if we lose the battle to control them,” said IDNR Marc Miller.

Wildlife managers spend more time carefully manipulating the physical and chemical environment of plants than in direct management of game animals since plants are the major component of both the habitats and the health of animal populations dependent upon them. The invasion by exotic plant species can turn high-quality habitat into degraded and undesirable habitat for wildlife.

Management tools including biological controls, prescribed burning, mowing, spraying and physically removing the plants by hand are available, but can be costly.

Increasing public awareness of invasive species is an essential goal because prevention and early intervention are the most effective and cost efficient approaches to address the economic and ecological impacts of exotic invasive species.

For more information on Illinois invasive species awareness and management efforts, go online to the IDNR website at

Invasive species often invade and replace the native flora in a variety of ways and will sometimes out-compete the native species to the extent the native plants totally disappear from an area.

Garlic mustard and the exotic buckthorns block needed sunlight, making it impossible for many of the needed native species to survive and reproduce. Such degraded habitats can quickly become a monoculture of only garlic mustard or buckthorn, meaning no food or shelter for native fish and game. Chemical toxins inhibiting growth of all other plants nearby are produced by garlic mustard and tree of heaven; these toxins are released from their roots into the surrounding soil, thereby eliminating competition for space, water, nutrients, etc. from other plants.The eliminated native species, in some cases, are very important food plants for native game animals. Because of the extirpation of many of native plants, a number of wild areas that once supported healthy populations of deer, elk, and other wildlife are no longer prime habitat for the species in question.

Bush honeysuckles not only shade out most native plants, but they also form such thick stands of growth that hunters and anglers cannot walk through the area or see game from a blind or tree stand. Multiflora rose, with its strong thorns and tangled growth habit, forms thickets even deer and turkeys find inhospitable for protection. Such tangled growths of honeysuckle, multiflora rose and other similar invasive plants often destroy the attractiveness of what was once prime habitat for hunting, fishing, birding and mushrooming.

Chinese bittersweet and porcelain berry grow to the tops of the tallest trees in the forest, creating dense, smothering foliage – and the weight of the vines will eventually pull the trees down.

Many undesirable invasive species will compete more successfully than native flora for water, minerals, and other necessary nutrients, leading to very poor growth of the native plants. Replacement of the native flora with invasive species reduces the biodiversity of the area since invasion by only one species often results in the loss of several native species. This loss of biodiversity is of major concern to ecologists both locally and globally.

Exotic plants are introduced into new areas in a myriad of ways. The seeds of some plants pass through the digestive systems of many animals, including some birds, without being damaged. Some seeds are widely scattered by wind before germinating in habitat suitable for their growth and reproduction. Many of the smaller seeds, such as garlic mustard, are so small they are carried in the fur of raccoons, dogs, deer, horses and other animals, only to drop off as the animals move into new habitat. Others, such as leafy spurge and teasel seeds, collect on roadside mowers only to fall off farther down the road accounting for the linear distribution of some exotic plants along our roads and railroad rights-of-way.

Oftentimes, people trim plants growing in their yards and gardens without thinking about proper disposal of the still-living cuttings which are then dumped into an area where they take root. Cuttings, stem pieces, and rhizome fragments can be blown about or carried downhill in runoff after a heavy rain before finding a new place to grow. Kudzu, honeysuckles, periwinkle, English ivy and Chinese Yam are just a few examples of plants that have invaded new areas in this manner.

Many of today’s exotic invasive species, such as burning bush, wintercreeper, periwinkle, Callery pear, and the ornamental figs, were grown for years before they exploded into the natural landscape and became problems. Landscapers used more than 60 species of imported ornamental figs in Florida for several decades without any problems until the

For boaters and anglers, a reminder that invasive fish, snails, plants, disease, and viruses can be transmitted by dumping bait or even just the water from bait buckets, bilges, live wells, trailers, and equipment used on the water. Administrative rules in Illinois prohibit the removal of natural water from waterways of the state via bait bucket, livewell, bait well, bilges or any other method. Regulations also prohibit removal of any watercraft, boat, boat trailer or other equipment from waters of the state without emptying and draining any bait bucket, ivewell, baitwell, bilge any other compartment capable of holding natural waters. Regulations also prohibit using wild-trapped fishes as bait within Illinois, other than in the waters where they were legally taken. To protect Illinois waters, inspect your boats and trailers for visible contamination of plants, mud, or water in bilges.

By removing, cleaning, or draining the equipment, you help eliminate invasive species from establishing in Illinois waters.

An invasive species of significant concern in Illinois is Asian carp. Unfortunately all four species of Asian carp – bighead, silver, grass and black carp – have been found in Illinois waters, likely escaping aquaculture facilities of the southern U.S. Bighead and silver carp are the focus of state, local, and federal efforts to reduce the populations and to keep this invasion from expanding into other watersheds, such as the Great Lakes.

Check the website at for updates of the Asian Carp Regional Coordinating Committee actions.