Consumer effects decline with prey diversity

While consumer species diversity is known to influence the capture of limited resources, little is known about how prey diversity impacts the transfer of energy and matter among trophic levels. Here, we perform a meta‐analysis of experiments that have examined the impact of grazers on the biomass of...

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Bibliographic Details
Published in:Ecology letters 2004-03, Vol.7 (3), p.192-201
Main Authors: Hillebrand, Helmut, Cardinale, Bradley J.
Format: Article
Language:English
Subjects:
Biodiversity
ecosystem functioning
grazing
meta-analysis
periphyton
resistance
trophic structure
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Summary:While consumer species diversity is known to influence the capture of limited resources, little is known about how prey diversity impacts the transfer of energy and matter among trophic levels. Here, we perform a meta‐analysis of experiments that have examined the impact of grazers on the biomass of periphytic algae to test the hypothesis that the magnitude of consumer (grazer) effects on prey (algae) depends on the species diversity of the prey assemblage. The analysis reveals that consumer effects tend to decrease as the diversity of a prey assemblage increases. This trend is robust for several different, yet complementary indices of grazer effect size and algal diversity. The trend also remains significant after statistically controlling for a variety of factors that can covary with prey diversity among studies. We discuss several possible mechanisms for the documented pattern, such as diversity enhancing the probability of inedibility and of positive interactions.
ISSN:1461-023X
1461-0248
DOI:10.1111/j.1461-0248.2004.00570.x