Historically, the wetlands of the Illinois River valley (IRV) provided extensive and valuable habitat to migrating waterbirds and other wetland-dependent wildlife in the Upper Midwest (Havera 1999). The Nature Conservancy’s Emiquon Preserve (2,700 ha) is a portion of a former floodplain of the Illinois River that was farmed for >80 years, isolated behind river levees, and has been undergoing restoration to a complex of wetlands and uplands since 2007. Since hydrology returned in 2007, we have monitored key ecological attributes (hereafter, KEAs) of specific biological characteristics or ecological processes related to waterbird communities and their habitats. Wetland vegetation communities and associated cover types have increased almost 700% since 2007, expanding from 255 ha to 2022 ha in fall 2016. Aquatic bed vegetation has comprised >50% of Emiquon Preserve since 2009, but important emergent plant communities have declined in recent years as the complex reached the lake marsh stage due to elevated and stabilized water levels (van der Valk and Davis 1978). Waterfowl and other waterbirds visit Emiquon Preserve in great numbers each fall and spring migration, with species such as American coot, northern pintail, green-winged teal, and gadwall selecting Emiquon compared to other wetlands and lakes in the IRV. The abundant aquatic bed and hemi-marsh plant communities collectively provide more food for waterbirds than do other nearby wetlands, such as the south pool of Chautauqua National Wildlife Refuge. Consistent with the >30 million energetic use days provided annually during 2013–2015 at Emiquon Preserve, dabbling and diving duck behaviors were dominated by feeding indicating the importance of the aquatic plant communities as foraging habitat. Emiquon also provides breeding habitat for species of conservation concern, such as common gallinule, black-crowned night herons, least bitterns, and American bitterns, as well as several species of ducks, geese, and swans. However,
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we have noted recent declines in persistent emergent vegetation, moist-soil vegetation, brood counts which act as an index of waterbird productivity, duck use days during fall migration, and invertebrate abundance during brood-rearing periods, which we assume is related to the transition of Emiquon Preserve into the lake marsh stage. Consequently, Emiquon Preserve is currently undergoing an extensive drawdown to reverse declining trends in wetland health and corresponding waterbird use. Future monitoring will assess the effects of drawdown on emergent vegetation communities and the response of wildlife in the system.The Nature Conservancyunpublishednot peer reviewedOpe
