Predator diversity enhances secondary production and decreases the likelihood of trophic cascades

E.J. O'Gorman, R.A. Enright, Mark Emmerson

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)


We manipulated the diversity of top predators in a three trophic level marine food web. The food web included four top benthic marine fish predators (black goby, rock goby, sea scorpion and shore rockling), an intermediate trophic level of small fish, and a lower trophic level of benthic invertebrates. We kept predator density constant and monitored the response of the lower trophic levels. As top predator diversity increased, secondary production increased. We also observed that in the presence of the manipulated fish predators, the density of small gobiid fish (intermediate consumers) was suppressed, releasing certain groups of benthic invertebrates (caprellid amphipods, copepods, nematodes and spirorbid worms) from heavy intermediate predation pressure. We attribute the mechanism responsible for this trophic cascade to a trait-mediated indirect interaction, with the small gobiid fish changing their use of space in response to altered predator diversity. In the absence of top fish predators, a full-blown trophic cascade occurs. Therefore the diversity of predators reduces the likelihood of trophic cascades occurring and hence provides insurance against the loss of an important ecosystem function (i.e. secondary production).
Original languageEnglish
Pages (from-to)557-567
Number of pages11
Issue number3
Publication statusPublished - Dec 2008

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


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