Food web modeling is recognized as fundamental to understanding the complexities of aquatic systems.Ecopath is the most common mass-balance model used to represent food webs and quantify trophic inter-actions among groups. We constructed annual Ecopath models for four consecutive years during the firsthalf-decade of a zebra mussel invasion in shallow, eutrophic Clear Lake, Iowa, USA, to evaluate changesin relative biomass and total system consumption among food web groups, evaluate food web impactsof non-native common carp and zebra mussels on food web groups, and to interpret food web impactsin light of on-going lake restoration. Total living biomass increased each year of the study; the majorityof the increase due to a doubling in planktonic blue green algae, but several other taxa also increasedincluding a more than two-order of magnitude increase in zebra mussels. Common carp accounted for thelargest percentage of total fish biomass throughout the study even with on-going harvest. Chironomids,common carp, and zebra mussels were the top-three ranking consumer groups. Non-native commoncarp and zebra mussels accounted for an average of 42% of the total system consumption. Despite the rel-atively high biomass densities of common carp and zebra mussel, food web impacts was minimal due toexcessive benthic and primary production in this eutrophic system. Consumption occurring via benthicpathways dominated system consumption in Clear Lake throughout our study, supporting the argumentthat benthic food webs are significant in shallow, eutrophic lake ecosystems and must be considered ifecosystem-level understanding is to be obtained.
Available at: http://works.bepress.com/clay_pierce/45/