Omnivory and grazer functional composition moderate cascading trophic effects in experimental <Emphasis Type="Italic">Fucus vesiculosus</Emphasis> habitats |
| |
Authors: | Britas Klemens Eriksson Christiaan van Sluis Katrin Sieben Lena Kautsky Sonja Råberg |
| |
Institution: | (1) Department of Marine Benthic Ecology and Evolution, Centre for Ecological and Evolutionary Studies, University of Groningen, P.O. Box 11103, 9700 CC Groningen, The Netherlands;(2) Department of Botany, University of Stockholm, 106 91 Stockholm, Sweden |
| |
Abstract: | We tested the relative strength of direct versus indirect effects of an aquatic omnivore depending on the functional composition
of grazers by manipulating the presence of gastropod and amphipod grazers and omnivorous shrimp in outdoor mesocosms. By selectively
preying upon amphipods and reducing their abundance by 70–80%, omnivorous shrimp favoured the dominance of gastropods. While
gastropods were the main microalgal grazers, amphipods controlled macroalgal biomass in the experiment. However, strong predation
on the amphipod by the shrimp had no significant indirect effects on macroalgal biomass, indicating that when amphipod abundances
declined, complementary feeding by the omnivore on macroalgae may have suppressed a trophic cascade. Accordingly, in the absence
of amphipods, the shrimp grazed significantly on green algae and thereby suppressed the diversity of the macroalgal community.
Our experiment demonstrates direct consumer effects by an omnivore on both the grazer and producer trophic levels in an aquatic
food web, regulated by prey availability. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|