Dreissena and benthos: exploring mechanisms of facilitation and competition

Session: Poster Session

Sonya Bayba, Great Lakes Center, baybas01@mail.buffalostate.edu
Lyubov Burlakova, Great Lakes Center at SUNY Buffalo State , burlakle@buffalostate.edu
Alexander Karatayev, Great Lakes Center at SUNY Buffalo State, karataay@buffalostate.edu
Robert Warren, Biology Department, SUNY Buffalo State, warrenrj@buffalostate.edu
Elizabeth Hinchey Malloy, U.S. EPA GLNPO, hinchey.elizabeth@epa.gov
Katie Bockwoldt, ORISE - US EPA GLNPO, bockwoldt.katelyn@epa.gov

Abstract

Invasive Dreissena r. bugensis (quagga mussels) are abundant in littoral, sublittoral and profundal areas of Lake Michigan, causing large shifts in benthic and pelagic communities. In the littoral zone, dreissenids increase food availability through deposition of feces and pseudofeces while also providing additional benthic habitat, which may result in short range facilitation. In profundal zones quagga mussels intercept the limited food supply through filter-feeding, which may result in long range competition. However, due to the presence of large populations of quagga mussels in the profundal zone, the positive effects of short-range facilitation may be impacting certain profundal benthic species. To detect long-range competition and short-range facilitation between Dreissena and various benthic species, we used 2015 Lake Michigan Cooperative Science and Monitoring Initiative benthic survey data to examine changes in diversity, abundance and average organic matter tolerance of benthic communities along various gradients such as: Dreissena density, sediment organic matter concentrations, and depth. Communities were assessed using non-parametric multivariate analyses and linear models. We found that the diversity and abundance of most benthic taxa and tolerance groups were affected by Dreissena, but the effect was depth-dependent.