Illinois Natural History Survey - University of Illinois

INHS Studies of the Illinois River


This special issue of Illinois Natural History Survey Reports is published to highlight some of the biotic research and monitoring of the Illinois River ecosystem that illustrates the unique challenges and opportunities emerging for river restoration. The Illinois River basin is the only large watershed occurring almost entirely within our borders. The river starts southwest of Chicago at the confluence of the Des Plaines and Kankakee rivers and flows 272.9 miles across the state to the Mississippi River at Grafton. It is of unique importance because it acts as an aquatic gateway between the Great Lakes and Mississippi River ecosystems through a connecting canal built during the late 1890s. It is also unique because the river valley below Hennepin once carried the Mississippi River, and thus has a wider and more developed floodplain than might be expected for a river of its size.

Stephen A. Forbes, the founding Chief of the Illinois Natural History Survey, began studies of the Illinois River in the 1870s. He reported that 85% of the fish species found in the state occurred in the Illinois River. In 1908, fish yields in the lower Illinois made up 10% of the U.S. fish catch. Without a doubt this was one of the more productive river ecosystems in the nation.

There is renewed interest in the Illinois River system and efforts are now being aimed at rehabilitating the river to an ecologically functional system. This restoration must occur in the face of numerous human-induced disturbances associated with urban and rural land uses, dikes along the river proper, and locks and dams for navigation. The role of the INHS in this ongoing and long-term effort has been and will continue to be to provide a scientific basis for management and rehabilitation actions, and monitoring our progress will permit any midcourse corrections.

Although we should not delude ourselves into believing that we can or perhaps even should return the river to its pre-Columbian pristine state, the mighty Illinois and its contiguous lands can again act as a functioning ecosystem with many of its former aesthetic, recreational, biologically diverse, scientific, and ecological service values. The seven articles contained within this special issue typify some of the research that has and is being conducted on the river by Survey scientists.

One paper included in this issue of Reports highlights the long-term studies of waterfowl that have occurred in the watershed and documents the decline in waterfowl populations that has come with changes in the river. Another article highlights the changes that have occurred in freshwater mussel populations. Two papers discuss invasive species in the river, Asian carp and plankton species. One study on invasive species that is not discussed here is the monitoring that is occurring on the round goby and an evaluation of the effectiveness of an electric barrier to keep the species out of the Illinois River (it is moving downstream from Lake Michigan). There is also a discussion of two different long-term monitoring programs for fish and our contributions to the development of the Illinois River Decision Support System, an endeavor being led by the Illinois State Water Survey to bring together on the Web all pertinent data on the river.

The INHS has had a long-term commitment to studies on the valuable resources of the Illinois River. In 1894, Stephen A. Forbes established a field station for research and education at Havana, Illinois, which today is represented by our Forbes Biological Station. We also have two field stations on the river to carry out the USGS Long Term Monitoring Program (LTRMP), one located at Havana and the other in Brighton, Illinois. In addition, we have been working with the Department of Natural Resources and Environmental Sciences at the University of Illinois and with Lewis and Clark Community College to establish a Great Rivers Research and Education Center near Alton, Illinois. There is no doubt that the confluence of the Illinois, Missouri, and Mississippi rivers represents a unique location for the study of large rivers.

For Illinois, the Illinois River is a treasure, one that ranks with the Everglades, Chesapeake Bay, and the Columbia River in its ecological and societal importance. I would urge all citizens to rally around the state's conservation programs (from its successful Conservation Reserve Enhancement Program to Illinois Rivers 2020) aimed at the river's rehabilitation. The INHS continues to embrace its role as the provider of sound biological data on the Illinois River and on the changes that continue to take place in its biotic populations. We look forward to those efforts that will improve the health of the basin and encourage your comments on our efforts.

David L. Thomas, Chief of the Illinois Natural History Survey

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