Predicting the Consequences of Dreissenid Mussels on a Pelagic Food Web

Document Type



Biology (HMC)

Publication Date



Although abundant in marine systems, hard substratum fouling organisms with high fecundity and large dispersal capability are rare in freshwater ecosystems. A noteworthy exception is a recent invader of North American lakes and rivers, the zebra mussel, Dreissena polymorpha. Consequences of this novel ecological type in these systems are not fully understood. Using computer simulations we modelled the potential consequences of Dreissena abundance for lake planktonic community structure along a nutrient gradient, using Green Bay of Lake Michigan as an example. We constructed a model of food-web interactions that accurately reproduces abundances of phytoplankton and zooplankton along this nutrient gradient. To this model we added consumption and filtration rates of Dreissena at varying densities. Model results indicate that Dreissena have strong negative effects on large phytoplankton, with chlorophyll reduced up to 80% as compared to the same community without zebra mussels. Results also indicate that Dreissena have relatively small effects on nanoplankton and herbivorous zooplankton. Effects are qualitatively similar along the nutrient gradient, and are strongest at the most eutrophic site. The effects of zebra mussels on the abundance of small phytoplankton and zooplankton were far less than the effects of nutrient levels along the gradient. The effects of zebra mussels on the large phytoplankton, however, were in the same order of magnitude as the effects of the nutrient gradient.

Rights Information

Copyright © 1996 Published by Elsevier Science B.V.