Introduction: The ecology of a river floodplain and the Emiquon preserve

Scientific study of the Illinois River began before a century of anthropogenic change, thus providing a unique perspective for describing river ecology restoration. In this issue, we explain how systematic monitoring revealed patterns in the restoration of the 2723-ha Emiquon Preserve on the Illinois River. The papers describe (1) how planktonic microorganisms, vegetation, fish, and waterbird communities responded rapidly to flooding of former shallow lakes and wetlands that had been drained and used for dryland agriculture for 83 years; (2) how variation of hydrologic conditions favors biotic community diversity and conditions for carbon sequestration; (3) how fish populations imposed a trophic cascade and affected diversity, yet may not help control some undesirable fish species; and (4) how simulation models are useful in planning, but that restoration practice and management decisions must adapt to present conditions, involve trade-offs, and are influenced by competing stakeholder interests. Unsurprisingly, water level management remains the most important factor in the restoration ecology of floodplains; however, the establishment of a river-floodplain connection should be managed to achieve a balance between establishing hydrology that mimics natural flood pulses while minimizing contemporary threats, including excessive nutrient and sediment loads and invasive species.