Landscape-Scale Wetland Habitat Rehabilitation and Management in Western Lake Erie: Changing a Paradigm Through Cooperation

Great Lakes coastal wetlands provide many important ecological functions and values, but most of these highly productive systems have been degraded or destroyed by anthropogenic stressors, including hydrologic isolation.  The multidimensional nature of wetland degradation presents challenges for habitat rehabilitation, but rehabilitation efforts designed to mimic natural processes are yielding positive results.  Fish assemblages, plant assemblages, and abiotic data in the Crane Creek coastal and diked wetland complex (U.S. Fish and Wildlife Service, Ottawa National Wildlife Refuge, Lake Erie) were sampled quantitatively to characterize spatial and seasonal patterns of fish assemblages. We also examined the implications for habitat rehabilitation if diked wetlands were hydrologically reconnected to Lake Erie.  Fyke netting captured fifty-three species and a large abundance of fishes in Crane Creek, but fewer than half of those species and a much smaller number of fish were captured in the adjacent diked wetlands.  A Dual-frequency IDentification SONar (DIDSON), a developing technology able to collect high-resolution fisheries data day or night in very shallow turbid water, revealed an extremely large abundance and flux of fishes moving between coastal wetland habitats and Lake Erie.  Although located adjacent to Lake Erie, there were pronounced differences in hydrology (water-level fluctuation), fish assemblages (composition, abundance, flux), and wetland vegetation (composition) between the diked and coastal wetlands.  Our results suggest that a fish-passage structure in dikes and periodic management actions could improve habitat and restore seasonal access to Lake Erie fishes.  Specifically, management actions involving the hydrologic reconnection of the diked wetlands could be used to mimic intermediate levels of disturbance and maintain wetland vegetation.  If implemented in a coordinated manner on a landscape scale, our recent research suggests that hydrologic reconnection and cyclic isolation of existing diked wetlands could lead to a new strategy for Lake Erie coastal wetland rehabilitation that maximizes ecological benefits on multiple spatial and temporal scales.