EARLY HEARING DETECTION AND INTERVENTION VIRTUAL CONFERENCE
MARCH 2-5, 2021

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6/08/2017  |   3:00 PM - 3:15 PM   |  REDUCTION IN COMMUNITY BODY SIZE EFFECTS THE STRENGTH OF TROPHIC CASCADES   |  306B

REDUCTION IN COMMUNITY BODY SIZE EFFECTS THE STRENGTH OF TROPHIC CASCADES

Mechanisms that control trophic cascade strength have been predominantly focused on environmental factors or food web linkages, but biotically driven compensatory mechanisms have notbeen as thoroughly explored. A three by two factorial design was used to test the hypothesis that plasticity and range in size frequency distribution of primary consumers influences the effects of top predators on primary producers. Specifically, the effects of planktivorous bluegill (Lepomis macrochirus) on phytoplankton were evaluated with three zooplankton treatments including small zooplankton (Moina micrura), large zooplankton (Dahnia pulex), and a mixture of the two. Bluegill preferentially consumed large zooplankton and reduced zooplankton biomass in all treatments. Phytoplankton chlorophyll a increased among all treatments with fish, but increased more rapidly and to a greater peak concentration in the treatment with Daphnia. Weaker effects in treatments with the small and mixed size zooplankton despite reductions in zooplankton biomass are likely because reduced size corresponds with a higher ratio of production to biomass; trophic response of invertebrates to predation from fish can be simultaneously directional for biomass and homeostatic for production.

  • C32 Primary and Secondary Production
  • C03 Invertebrates
  • C25 Food Webs

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Presenters/Authors

Thomas Detmer (), University of Illinois, tdetmer@illinois.edu;


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David Wahl (), University of Illinois, d-wahl@illinois.edu;


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