Invertebrate availability in flooded agricultural habitats of the upper midwest

Recent estimates suggest that over 80% of the wetlands of the continental US have been lost. Until recently, the majority of wetland loss was due to conversion to agricultural systems.  Although there are obvious, clearly documented detrimental effects of wetland conversion, there is also substantial evidence that wetland-dependent birds exploit flooded agricultural fields for energy during spring migration.  The majority of this research, however, has been limited to flooded rice fields.  In this project, we determined the availability of aquatic invertebrate prey in agricultural habitats (primarily corn fields) that receive periodic flooding during spring (likely historical wetlands converted to agriculture) in the upper Midwest.  Our goal was to determine the availability of invertebrate prey in these flooded agricultural areas for wetland-dependent bird consumption during their spring migration.  Currently, most resource managers assume the majority of food available to wetland-dependent birds in these habitats is represented by waste grains left after harvest activities.  Our findings suggest that although invertebrate community composition is limited to relatively tolerant taxa, invertebrate biomass in these habitats may also be an important food resource for waterfowl and other water birds using these systems.