Invasive Plants

by Sierra Chmela

Invasive plants are nonnative species which often have a detrimental effect on local flora and fauna. Invasive seeds can arrive via animals’ coats or scat, wind, or human activity. These plants can be difficult to control due to a myriad of factors including natural resilience to disturbances and production of a high number of seeds.

Over countless years, ecosystems have evolved a balance. A healthy ecosystem has numerous niches which are filled by native plants and animals that come to rely on each other for food, reproduction, and shelter. When an invasive plant moves into an area it can outcompete native species and take over these niches. This then has a cascading effect on the rest of the ecosystem. For example, an invasive plant could take over an area, making it extremely difficult for other species to survive. This could result in certain animals or pollinators being unable to find their preferred food source. Invasive species can also lead to increased erosion and a reduction in water quality by replacing plants with deeper and more comprehensive root systems.

Unfortunately, Illinois is host to dozens of invasive plant species, many of which, like tree-of-heaven and common buckthorn, can be found right here in Lincoln Park. However, some invasives can be tricky to identify because they look similar to native species. One example is Oriental bittersweet (Celastrus orbiculatus, pictured above), an invasive vine which can be easily confused for American bittersweet (Celastrus scandens). These plants have strikingly similar leaves in spring and summer but during the fall and winter a few key differences are revealed. Both species produce seed capsules which open to expose red berries. However, Oriental bittersweet berries appear along the entire length of the stem while the berries of American bittersweet congregate at the stems’ ends. Furthermore, Oriental bittersweet has yellow seed capsules while those of American bittersweet are orange.

Conservancy staff and volunteers monitor and remove invasive species in the natural areas of Lincoln Park, both through weeding and by planting thousands of native plants annually. You can help reduce the spread of invasive species by gardening with native plants and cleaning your shoes between walks, especially when moving between parks!