The survival of native plants in natural areas of Illinois frequently is threatened by various factors. Loss of habitat is one factor that may put native plants at risk. Habitat may be destroyed due to urban sprawl, agricultural production or other human-related activities that alter the environment of natural areas such as changes in flow of rivers, alternation of drainage patterns or removal of wetlands.
Another factor that may affect native plants in natural areas is competition by invasive pest species including both plants and animals. Unfortunately, many of the invasive plants were brought to Illinois as garden plants. These exotic invasive plants compete so effectively with native plant species that they frequently eliminate or drastically reduce the numbers of certain native plant species.
The impact resulting from loss of habitat and introduction of invasive species on natural ecosystems is to reduce species diversity, which causes some species to become endangered or threatened. Hence, by helping to establish alternative habitats for native plants in gardens, we also may help to protect certain species from extinction as gardens can provide connecting points between the few isolated remaining natural areas in Illinois.