Carlyle Lake, a man-made 26,000-acre multipurpose lake is at the southwestern tip of Fayette County and owned by the U.S. Army Corps of Engineers. It is bounded by U.S. Route 127 on the west, Us. Route 51 to the east, Route 50 to the south. Interstate 70 is about 15 miles north.
The Illinois Department of Natural Resources leases more than 9,000 acres of the land to manage various habitats for food, shelter and breeding places for wildlife. These habitats include woodland, open water, wetlands, grassland and cropland.
Carlyle Lake includes 80 miles of tree-lined shores in southern Illinois, 80 miles south of Springfield and 50 miles east of St. Louis. Eldon Hazlet State Park, owned by the Illinois Department of Natural Resources within Carlyle Lake contains deciduous forests, shrubs and thickets.
Archaeological studies show prehistoric Americans first entered the Carlyle Lake area 10,000 years ago, roaming the prairies and riverways; settlers founded the city of Carlyle in the 1800s after which the lake is named.
Also, included in the Carlyle Lake Complex IBA are Vandalia Bottoms and Keck's Marsh.
Keck's Marsh is a privately owned and commercially managed farm and hunt club. Much of the land is devoted to agriculture with the balance in a mixture of hardwood bottoms and marsh or slough areas. The fringe tracts consist of upland agriculture, hardwood timber, and CRP fields. The marsh is seasonally flooded to provide habitat for migrating waterfowl along with naturally flooded areas. The management plan provides a diverse mix of habitat and food resources for a variety of wildlife.
Vandalia Bottoms, comprised mostly of private farmlands, floods most years creating large areas of shorebird habitat. Multiple creeks east of this area channel into the "Vandalia Ditch" which appears to provide much of the water and food source for these flooded fields.
Carlyle Lake contains some of the largest waterfowl concentrations in the state. For example, surveys tabulated 47,445 individual ducks on Feb. 11 2002. That number did not even include the 61,655 Mallards, 2,500 Snow Geese, and 500 Canada Geese reported on the site.
This site was chosen as an IBA because it met the criteria for concentrations of waterfowl, shorebirds, and migrants.
Threats at Carlyle include impacts from recreational uses, potential developments, and the effects of water level changes behind the dam.