Variation in invertebrate diets among wetland types: an application of stable isotope mixing models to food web comparisons

Wetland function is an aspect of management that is poorly understood. Macroinvertebrates are known to have a role in these functions, but characterization of these roles is not clear, particularly for groups such as chironomid larvae and crustaceans. During 2006 and 2007, I sampled non-Tanypodinae chironomid larvae and select crustaceans from different southeastern wetland sites, along with their potential food sources. These samples were prepped for stable isotope analysis, and run for stable isotopes of carbon and nitrogen. EPAs IsoSource mixing model was used to highlight important and unlikely foods. Comparisons between forested and herbaceous wetlands within the same region suggest detrital sources are more important in forested wetlands than in herbaceous wetlands. Algae was found to be an important resource for midge larvae in all wetland types.