Network structure, predator - Prey modules, and stability in large food webs

Stefano Allesina, Mercedes Pascual

Research output: Contribution to journalArticlepeer-review


Large, complex networks of ecological interactions with random structure tend invariably to instability. This mathematical relationship between complexity and local stability ignited a debate that has populated ecological literature for more than three decades. Here we show that, when species interact as predators and prey, systems as complex as the ones observed in nature can still be stable. Moreover, stability is highly robust to perturbations of interaction strength, and is largely a property of structure driven by predator - prey loops with the stability of these small modules cascading into that of the whole network. These results apply to empirical food webs and models that mimic the structure of natural systems as well. These findings are also robust to the inclusion of other types of ecological links, such as mutualism and interference competition, as long as consumer - resource interactions predominate. These considerations underscore the influence of food web structure on ecological dynamics and challenge the current view of interaction strength and long cycles as main drivers of stability in natural communities.

Original languageEnglish (US)
Pages (from-to)55-64
Number of pages10
JournalTheoretical Ecology
Issue number1
StatePublished - Mar 2008


  • Complexity/stability
  • Food webs
  • Predator - prey
  • Sign-stability
  • Weak interactions

ASJC Scopus subject areas

  • Ecology
  • Ecological Modeling


Dive into the research topics of 'Network structure, predator - Prey modules, and stability in large food webs'. Together they form a unique fingerprint.

Cite this