Because recent studies in lakes and rivers indicate that trophic interactions strongly influence community structure, it might be expected that such interactions would similarly influence wetland communities. However while the primary producers examined in most lake and river studies were live plants, most consumable primary production in wetlands is detritus. Thus food web dynamics in wetlands probably differ from those in other aquatic systems. Previous wetland researchers have manipulated the bottom-up force of detritus biomass but detritivore populations often don't respond; wetland detritivores may not be resource limited. Few investigations have examined how wetland detritivores are influenced by top-down forces of predation. Experiments that examine how bottom-up interactions with detritus and top-down interactions with predators concurrently affect populations of detritivorous midges are planned. Using enclosure/exclosure mesocosms (2 x 2 m) in a New York wetland, the following phenomena will be examined: midge responses to plant litter biomass, first- level predator densities (insects), and second-level predator densities (fish). The relative influences on midges of food and habitat heterogeneity from detritus will be determined. %%% Wetland habitats are arguably the least understood of all aquatic habitats and are the most endangered as well. These days, policy decisions regarding wetlands are being made with insufficient scientific information. In addition to addressing theoretical questions about wetlands, this work has implications for applied ecology because midges are important links between primary producers and higher level consumers (such as passerine birds and waterfowl).
