Perturbations to trophic interactions and the stability of complex food webs

E.J. O'Gorman, Mark Emmerson

Research output: Contribution to journalArticlepeer-review

112 Citations (Scopus)

Abstract

The pattern of predator-prey interactions is thought to be a key determinant of ecosystem processes and stability. Complex ecological networks are characterized by distributions of interaction strengths that are highly skewed, with many weak and few strong interactors present. Theory suggests that this pattern promotes stability as weak interactors dampen the destabilizing potential of strong interactors. Here, we present an experimental test of this hypothesis and provide empirical evidence that the loss of weak interactors can destabilize communities in nature. We ranked 10 marine consumer species by the strength of their trophic interactions. We removed the strongest and weakest of these interactors from experimental food webs containing >100 species. Extinction of strong interactors produced a dramatic trophic cascade and reduced the temporal stability of key ecosystem process rates, community diversity and resistance to changes in community composition. Loss of weak interactors also proved damaging for our experimental ecosystems, leading to reductions in the temporal and spatial stability of ecosystem process rates, community diversity, and resistance. These results highlight the importance of conserving species to maintain the stabilizing pattern of trophic interactions in nature, even if they are perceived to have weak effects in the system.
Original languageEnglish
Pages (from-to)13393-13398
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume106
Issue number32
Early online date03 Aug 2009
DOIs
Publication statusPublished - 11 Aug 2009

ASJC Scopus subject areas

  • General

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