Breeding Ecology of Waterbirds in a Restored Floodplain of the Illinois River Valley

Having directly restored, enhanced, and protected greater than 2,700 ha of former floodplain wetlands and associated uplands in the central Illinois River valley, the Nature Conservancy’s Emiquon Preserve is the most substantial floodplain restoration effort in the region to date. The restoration has provided critical nesting habitat for many waterbird species, including species of conservation concern such as Least Bittern, Black-Crowned Night Heron, and Common Gallinule. Since 2013, Forbes Biological Station has conducted nest searches in two distinct wetland vegetation communities, dense emergent and hemi-marsh vegetation. We evaluated nest density, nest success, and nest characteristics of marsh birds during June and July of each year. Nest searches were performed in random plots (0.2 ha) that were generated in ArcGIS and we also found nests incidentally when travelling between plots The addition of a water control structure in summer 2016 increased water management capabilities at Emiquon Preserve and restored river floodplain connectivity. In 2018 managers implemented a drawdown designed to restore moist soil vegetation and provide opportunity to perform levee repairs and this allowed us a unique opportunity to evaluate the effects of the drawdown on waterbird nesting ecology. We will compare data from summer 2018 with all previous monitoring years and compare estimates and characteristics of nest density and survival. This may provide valuable insight into how small habitat manipulations can have a large impact on marshbird breeding strategies. This multi-year research project will continue to provide information to adaptively manage and improve Emiquon Preserve and areas like it using nesting waterbirds as an environmental indicator and sentinel of wetland quality.