WETLAND INVERTEBRATE ABUNDANCES AND CORRELATIONS WITH WETLAND WATER NUTRIENTS

Invertebrates are important in aquatic food chains, forming the link between phytoplankton and higher level consumers such as waterfowl. We hypothesized that high concentrations of nutrients in wetland water would lead to high invertebrate abundances through transfer of nutrients and energy up the food chain. Three seasonal wetlands in agricultural landscapes of eastern South Dakota were sampled monthly from May through August in 1994 and 1995. Wetland water nitrate-N and orthophosphate concentrations were determined using a Hach DR 2000 spectrophotometer. Aquatic invertebrates were sampled using activity traps placed midway in the water column for 24 hours. Nitrate-N concentrations were low, ranging from 0.0 to 0.2 mg L -1 in both years.