A plague of waterfleas (Bythotrephes): impacts on microcrustacean community structure, seasonal biomass, and secondary production in a large inland-lake complex

• DOI: 10.1007/s10530-015-1050-9
• Publication Date: 2016-02-29T11:11:28Z
• Authors: W. Charles Kerfoot; Martin M. Hobmeier; Foad Yousef; Brenda Moraska La...; Ryan P. Maki; Jodi K. Hirsch
• Keywords: Bosmina; Diel vertical migration

The spiny cladoceran (Bythotrephes longimanus) is an invasive, predaceous zooplankter that expanding from Great Lakes coastal waters into inland lakes within a northern latitudinal band. In large, Boundary Water lake complex (largely Voyageurs National Park), we use two comparisons, 2-year spatial and 12-year temporal, to quantify seasonal impacts on food webs biomass, plus preliminary calculation of secondary production decline. Bythotrephes alters the biomass pattern by severely depressing microcrustaceans during summer early fall, when predator most abundant. Cladoceran cyclopoid copepods suffer serious population declines, although resistant Holopedium favored in comparisons. Microcrustacean reduced 40–60 % declines about 67 %. microcrustacean community shifts towards calanoid copepods. decline due both loss longer generation times (slower turnover). "top-down" perturbation appears hold across small, intermediate, large-sized (i.e. scale-independent), pronounced densities reach 20–40 individuals L−1. Induction tests with small cladocerans (Bosmina) suggest certain native prey populations do not sense exotic are "blind-sided". Failure deploy defenses could explain disproportionate New World versus Old lakes.