Invasive Species

Non-native Invasive plant species - Autumn Olive

The Battle – Non-Native Invasive Species

Invasive species and noxious weeds are a common sight on the Midewin landscape. Nearly 70 non-native, invasive plant species at Midewin threaten restoration, management, health, and safety.

Fire suppression and lack of management have allowed noxious weeds and invasive species to invade Midewin’s ecosystems.  Management of open land declined as U.S Army activities ceased, and many areas became invaded with invasive herbaceous vegetation and dense stands of shrubs and young trees. 


What is a Non-Native Invasive Species and Where Do They Come From?

Non-native invasive plants have been brought here from somewhere else, and they left their natural enemies, especially insects and diseases, behind.

Many of the plants we grow as crops, lawn, or garden flowers originate from Europe, Asia, or other places. Common wild plants, including dandelions, Queen Anne’s lace, clover, and crabgrass were brought here from other lands. While most of these non-native plants are beneficial to us, or at least benign, some do cause problems; these are the non-native invasive plants.

Some of these plants cause obvious damage, such as the weeds that infest farmland or gardens, and some invasive plants have a more insidious impact. These plants harm our natural heritage by changing native habitats and, displacing native wildlife and plants. Invasive species, both plants and animals, are now considered the #2 threat to endangered wildlife and plants. #1 remains habitat destruction.

Not all invaders are imported from other regions and countries. Native invasive plants also pose a threat to management and restoration of native vegetation and grassland habitat.  Native woody plants such as green ash, gray dogwood, hawthorns, smooth sumac, and sandbar willow are invading grassland and prairie communities, displacing desirable species and fragmenting grassland bird habitat. 


How Do They Threaten Prairie Restoration?

In many areas, non-native plant species heavily infest the existing native vegetation; for example, exotic species such as Canada bluegrass, common teasel, common mullein, and sweet clover are invading rare dolomite prairie habitat.  Reed canary-grass and common reed are aggressive invaders present in Midewin’s marshes, sedge meadows, moist grasslands, and wet dolomite prairie. 

Invasive species can form dense monotypic stands that can choke a wetland and displace desirable plant and animal species. 

They also reduce the effectiveness of ecosystem restoration by competing with desired species for light, nutrients, and water.  They alter habitat structure, contaminate native seed production, and alter hydrologic regimes in certain wetlands.


How Do You Combat Non-Native Invasive Species?

At Midewin, we attack invasive plants using many techniques. Restoring native habitats, such as tallgrass prairie, helps to provide competition for non-native plants. But, for the natives to get a foothold, we often must reduce infestations by hand-pulling, mowing, cutting, cultivating, and using compatible herbicides. No one technique works 100%, and we often use a combination of the above methods.

The Prairie Plan outlines the goal to reduce noxious and exotic invasive plant infestations and prevent new invader species from becoming established. This includes planning and implementing an Integrated Pest Management program for noxious weed and invasive species prevention and control. The Plan emphasizes areas where non-native invasive species have a high potential for establishment and spread.

The success of ecosystem restoration on Midewin will be compromised as long as invasive plant species and noxious weeds persist and continue to invade grassland and prairie communities.