Moist-soil plant seed production for waterfowl at Chautauqua National Wildlife Refuge, Illinois

The Illinois River Valley (IRV) is a critical ecoregion for migratory waterfowl. Significant wetland loss occurred in this region in the early 20 ^th Century, and remaining wetlands are subject to additional degradation via sedimentation, summer flooding from the Illinois River and invasive species. Managed moist-soil wetlands may provide quality foraging habitat for migrating waterfowl, but contemporary estimates of seed production and carrying capacity do not exist for the IRV. We evaluated seed production and carrying capacity of a 931-ha moist-soil wetland at Chautauqua National Wildlife Refuge in central Illinois during falls 1999-2001. Seed production varied annually (329-1231 kg/ha), but overall was greater than previously published estimates for other areas of North America. Estimated carrying capacity across years was 6.760 ± 411 (SE) duck use-days/ha; this value was 1.5-15.4 times greater than other published carrying capacity estimates for harvested corn, rice and soybeans. We recommend continued regional-scale research to estimate foraging carrying capacity of moist-soil wetlands for waterfowl in mid-latitude regions, such as the IRV or upper Mississippi River.