Invasive Predator, <Emphasis Type="Italic">Bythotrephes</Emphasis>, has Varied Effects on Ecosystem Function in Freshwater Lakes |
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Authors: | Angela L Strecker Shelley E Arnott |
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Institution: | (1) Department of Biology, Queen’s University, 116 Barrie St., Kingston, Ontario, Canada, K7L 3N6;(2) Present address: Department of Ecology & Evolutionary Biology, University of Toronto, 25 Harbord St., Toronto, Ontario, Canada, M5S 3G5 |
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Abstract: | Bythotrephes longimanus is an invertebrate predator that has invaded the North American Great Lakes and a number of inland lakes, where it preys
on crustacean zooplankton. We examined the effect of Bythotrephes on two measures of ecosystem function during a four-month observational study of freshwater lakes on the boreal shield. Bythotrephes-invaded lakes had significantly lower epilimnetic zooplankton abundance and production compared to reference lakes. On average,
Bythotrephes consumed 34% of zooplankton production when it was present in lakes. There was some evidence of changes in the timing of
zooplankton production, as well as shifts to cooler, less productive habitats, which may lessen the overall effect of the
invader on the transfer of energy to higher trophic levels. We experimentally demonstrated a weak trophic cascade where invader
predation reduced zooplankton biomass, and subsequently increased phytoplankton growth. However, the response was small in
magnitude and not biologically relevant at the whole lake-scale. The most conspicuous effect of Bythotrephes that we measured was a diversion of energy away from native predators at higher trophic levels.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. |
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Keywords: | invasive species ecosystem function crustacean zooplankton Bythotrephes freshwater lakes secondary production zooplankton grazing |
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