Drawdown and the changing wetland vegetation community at Emiquon Preserve

We monitored the response of wetland vegetation to restoration efforts at Emiquon Preserve during 2007–2020 relative to desired key ecological attributes identified by The Nature Conservancy (TNC). We mapped the wetland vegetation of Thompson and Flag lakes during fall of each year to document changes in wetland area, plant species composition, and vegetation assemblages. Spatial extent of wetland vegetation and other cover types grew rapidly during early years of restoration, and vegetation communities developed without supplemental planting or little hydrological manipulation. However, changes in vegetation communities observed in 2015-2016 suggested that the emergent marsh at Emiquon was in a state of decline. Consequently, TNC initiated a drawdown in 2016, and removed approximately 6 feet of water by July, 2018 to dry out the substrate and encourage regeneration of the marsh community. Since the drawdown, moist-soil vegetation has flourished, but emergent marsh communities have yet to return to a level seen during the initial restoration. We will present responsesof the major vegetation communities (i.e., aquatic bed, persistent emergent, hemi-marsh, non-persistent emergent, and open water), soil characteristics, and invasive plant species to the initial drawdown and water manipulations since, and relate our data to future management of Emiquon Preserve.