SEASONAL DYNAMICS OF AQUATIC FAUNA AND HABITAT PARAMETERS IN A PERCHED UPPER MISSOURI RIVER WETLAND

Abstract

The Missouri River floodplain historically contained numerous wetlands; however, alterations to the corridor have resulted in the loss of flood-pulse processes. The annual contributions of small wetlands ( 0.05; F 6.1; df=2,9) and collectively surpassed 3,200 organisms/L. These densities exceeded other regional means by as much as 900%. Twentyfour fish species were documented in the wetland; however, the black bullhead, Ameiurus melas Rafinesque, dominated the fish community. Wetland depth and surface area increased during the connection period and inundated terrestrial grasses and woody debris. Decay of submerged organic matter, combined with the lack of rooted macrophytes, loss of algal productivity to flushing, and higher turbidity, may have all contributed to reduced summer dissolved oxygen levels. Avian feeding activity suggested that fishes were using the upper water column when nearly anoxic lower water column conditions existed. Although the wetland habitat may be harsh, presence of juvenile fishes and dense zooplankton populations establishes the potential importance of these water bodies to the Missouri River ecosystem.