Diked wetlands can be found in the coastal zone throughout the Great Lakes. These productive wetlands often were hydrologically connected to the lakes before construction of earthen berms that limited water exchange and fish access. This makes them priority targets for coastal wetland rehabilitation through installation of fish-passage structures. Work starting in the mid-1990s at places like Metzger Marsh (Lake Erie) and Oshawa Second Marsh (Lake Ontario) tested early rehabilitation strategies including dike redesign and carp-exclusion systems in structures. Site-scale monitoring after those projects characterized a positive ecosystem response, but intense monitoring of subsequent reconnections in the Crane Creek wetland complex (Lake Erie), and later the Maankiki wetland complex (Lake Huron), revealed much more about when and how fish use the rehabilitated sites. These findings informed the reconnection of over 50 other diked wetlands to rehabilitate coastal wetland habitats throughout the basin, setting the stage for ongoing monitoring of project impacts at multiple sites across the landscape and aggregation of data to explore how the site-scale projects are impacting lake productivity, fisheries objectives, and other landscape-scale priorities. Supported by Great Lakes Coastal Wetland Restoration Assessment data, reconnection of diked wetlands and low elevation agricultural fields continues as a rehabilitation strategy within the basin.
