Several areas of importance in Ohio are the Killdeer Plains/Big Island Wetland Complex and the watersheds of the Scioto, Great and Little Miami, and Muskingum Rivers. The Killdeer Plains/Big Island Wetland Complex was originally the eastern-most extension of a large wetland and prairie complex that consisted of prairie pothole and oak savanna habitats. This region has been extensively drained and converted for agriculture. The Scioto River is a major tributary to the Ohio River, and its valley is a mosaic of broad floodplains, small streams, agricultural land, and bottomland forests. Much of this region has been cleared and drained for agriculture giving it a high potential and priority for restoration.
Minnesota and Iowa are also important areas once dominated by lakes and wetlands. Loss of wetlands and grasslands has diminished the waterfowl production capacity of this landscape, however it continues to provide vital waterfowl migration habitat that includes large marshes and shallow lakes on the prairie to natural wild rice wetlands in the forest. The large wetlands remaining serve as a vital link between southern wintering grounds and breeding areas to the north and west. During prairie droughts, more permanent water in Minnesota’s lake country offers refuge to displaced waterfowl. Although direct drainage no longer threatens these wetlands, recent research suggests that productivity in these wetlands has seriously declined and may be directly impacting waterfowl populations.
In Missouri and eastern Kansas, important migration and winter habitat occurs along the Missouri River and its major tributaries, including the Osage and Grand River systems. However, wetlands associated with these river systems have been severely degraded as a result of the effects of flood control and navigation projects. These projects dramatically altered natural hydrology of these rivers, and they have created disconnects between the rivers and their floodplains where most of the valuable wetland habitat was located. Subsequent to alterations of hydrology came conversion of many former wetland areas to agriculture and other uses. The net effect has been a reduction in waterfowl carrying capacity in the region.
Importance to waterfowl
Mallard nesting activity occurs throughout the Eastern Tallgrass Prairie, Prairie Hardwood Transition and the Central Hardwoods regions where there is suitable habitat, though little quantitative information is available. Wetland/grassland complexes provide beneficial breeding habitat for mallards and blue-winged teal. The bottomland hardwoods provide some of the best wood duck nesting and brood rearing habitat in the Upper Mississippi River Conservation Region. The breeding wood duck population in the Illinois River Valley is estimated at 20,000 (USFWS 1998). The Horicon Marsh and surrounding area provides some mallard and blue-winged teal production. Horicon supports the largest redhead breeding population east of the Mississippi River (WDNR 1973).
The Mississippi River and its major tributaries provide a major migration corridor for hundreds of thousands of dabbling ducks, and significant numbers of ring-necks, canvasbacks and scaup (USGS 1999). Managed areas and restored bottomland forests in the Eastern Tallgrass Prairie, Prairie Hardwood Transition and the Central Hardwoods regions provide wintering and migration habitat for mallards, black ducks, wood ducks, northern pintails, Mississippi Valley Population of Canada geese and other species. Horicon Marsh is a major migration stopover for the Mississippi Valley Population of Canada geese, with between 100,000 and 500,000 geese utilizing the marsh as they make their way from northern breeding grounds to wintering habitat in southern Illinois (Bellrose 1980). The Illinois River Valley and associated wetlands provide some of the most significant mid-migration habitat for mallards in the Mississippi Flyway, often peaking at over one million in the fall. Although not to the magnitude as the Illinois River, the River systems in Ohio provide important migration and wintering habitat for mallards and black ducks and other species crossing from the Atlantic coast, such as pintails.
The Missouri River and its major tributaries provide important migration habitat for mallards, green-winged teal, wood ducks and other puddle ducks, as well as Canada and snow geese. In years of mild winter weather, several hundred thousand waterfowl, particularly mallards, may over-winter in habitats associated with the Missouri River.
Current conservation programs
Within this Waterfowl Conservation Region, there area several significant areas in which DU delivers conservation programs. These include the Ohio Rivers area, Illinois River watershed, southeast and northwest Wisconsin, the Living Lakes area (MN and IA), and programs in Missouri.
The Illinois River watershed is a significant migration corridor. The number of mallards migrating through the valley has decreased by 65% and the number of divers, especially lesser scaup, have decreased by more than 90%. Despite these declines, 25% of all ducks I the Mississippi Flyway still use the Illinois River as a migratory corridor. The degradation of the system has also resulted in major non-point source pollution input to the Mississippi River ecosystem. Other significant areas in Illinois include the Rock River watershed for production and the confluence of the Ohio/Mississippi Rivers in southern Illinois and Indiana. In Illinois, the priority should be on diving duck migration habitat (fall and spring) mostly in the middle reach of the Illinois River. The second priority will be spring habitat for both dabblers and divers, and finally production in the upper reaches near Wisconsin.