Illinois Conservation Summary

Illinois is well known as the Prairie State, but there is much more ecological diversity here than the name implies. There are 14 natural divisions (geographic regions having similar topography, soils, bedrock, plants and animals) in Illinois and they contain a range of prairie, wetland and forested communities interspersed with agricultural and urban areas.

Rare Species and Characteristic Habitats

Once abundant in the prairie regions throughout the northern two-thirds of Illinois, thegreater prairie chicken population probably numbered in the millions; today, the majority of the population of a few hundred birds remains in two remnant flocks in south-central Illinois, and is under tremendous pressure from lack of genetic diversity and habitat loss. The timber rattlesnake once had an extensive range in the non-prairie areas of Illinois, but is now reported in less than half its former range; many historic populations of this species in Illinois have been decimated and many current populations are threatened by habitat destruction and indiscriminate killing. Because they hibernate in large numbers in only a few caves, Indiana bats are extremely vulnerable to disturbance; documented causes of decline in their population include disturbance during hibernation, change in structure or temperature of caves, loss and fragmentation of forested roost and foraging sites, and increases in pesticides and environmental contaminants, but a recent survey indicates that this state- and federal-endangered species’ population appears to be increasing in Illinois.

Public and Private Conservation Efforts

Despite the loss of over 90 percent of its original wetlands and nearly all of its original prairie, Illinois still contains several large-scale assemblages of species and natural communities, thanks to land-protection programs, conservation activities and various partnerships with federal, state, local and private agencies. Lost Mound National Wildlife Refuge, formerly known as the Savanna Army Depot, is notable for its immense grasslands and bottomland forest habitats. This area along the Upper Mississippi River is managed for migratory birds by the U.S. Fish and Wildlife Service. The site also contains some of the last remaining prairies of their kind in Illinois. The high-quality upland and wetland communities provide habitat for two federally listed species and 47 state-listed species.

Well over 90 percent of land in Illinois is privately owned, making conservation partnerships in Illinois an imperative. Roughly 87,000 acres of natural lands, both private and public, are preserved in the Illinois Nature Preserves Commission’s Nature Preserve and Land and Water Reserve land protection programs. Chicago Wilderness is a regional alliance with more than 230 diverse member organizations, both public and private, working together to restore local nature and improve the quality of life for all living things by protecting the lands and waters on which we all depend. Nearly 360,000 acres of natural areas make up Chicago Wilderness and an additional 1.8 million acres in Wisconsin, northeast Illinois into northwest Indiana, and southwest Michigan have been identified as prospective areas for protection and restoration. Other organizations, including The Nature Conservancy, Ducks Unlimited and Illinois Audubon Society, have protected thousands of acres of wetlands and bird habitat in Illinois and invested millions of dollars in statewide conservation programs.


The health of Illinois’ ecosystems is threatened by a number of issues including habitat degradation and loss, hydrological modifications, spread of exotic species, and economic constraints. In the Chicago collar counties, an area that hosts the greatest biodiversity in Illinois as well as the largest human population, the landscape is being developed at an astonishing rate. In many streams, decreased water quality and sedimentation, which affect the composition and structure of aquatic habitats, has placed considerable stress on fish, mussel and other aquatic species. The problem of exotics in Illinois is a widespread one with several species being the big players. Birds nesting in bush honeysuckle plants, which are lower to the ground than other nest plants, have seen an increased predation rate. Studies have shown that the chemical exuded from the roots of garlic mustard inhibit spring flower and other plant growth. Garlic mustard has also taken over much of the habitat occupied by the State-endangered eastern massasauga. Economic constraints challenge Illinois to find innovative funding opportunities to perform needed management in native habitats.

Illinois’ Future

Despite these challenges, the people of Illinois are dedicated to the conservation of the state’s rich natural heritage. This support has been demonstrated by the overwhelming endorsement of programs and initiatives to protect the natural environment. In addition, the Illinois Wildlife Action Plan is helping to foster and focus conservation partnerships and activities. Through the combined effort of committed individuals and organizations, the health of Illinois’ natural environment can be conserved for future generations.

Contribute to LandScope

Want to join, work with us or simply find out more? Learn how you can get involved.


Copyright © 2021 NatureServe. All Rights Reserved.