Changes in the Lake Superior Crustacean zooplankton community

We examined crustacean zooplankton densities at five locations in two regions of Lake Superior during a time period that spanned two decades, for three years in the early 1970's and again for three years in the early 1990's. We used coupled multivariate and univariate analyses to find whether the zooplankton community had changed over these decades, and to determine if such changes had occurred consistently across all stations. Seasonal variation was also examined. We found that the structure of the zooplankton community changed in directions predicted by the concurrent increase in the abundance of a major endemic planktivore, the lake herring (Coregonus artedi). The presence and abundance of various species in different habitats also varied within a year, between years, and between decades. The spatiotemporal scale of this study confirms that size-selective planktivory may produce community-wide effects in large lakes.