Biotic mechanisms of community stability shift along a precipitation gradient

Lauren M. Hallett, Joanna S. Hsu, Elsa E. Cleland, Scott L. Collins, Timothy L. Dickson, Emily C. Farrer, Laureano A. Gherardi, Katherine L. Gross, Richard J. Hobbs, Laura Turnbull, Katharine N. Suding

Research output: Contribution to journalArticlepeer-review

96 Scopus citations


Understanding how biotic mechanisms confer stability in variable environments is a fundamental quest in ecology, and one that is becoming increasingly urgent with global change. Several mechanisms, notably a portfolio effect associated with species richness, compensatory dynamics generated by negative species covariance and selection for stable dominant species populations can increase the stability of the overall community. While the importance of these mechanisms is debated, few studies have contrasted their importance in an environmental context. We analyzed nine long-term data sets of grassland species composition to investigate how two key environmental factors, precipitation amount and variability, may directly influence community stability and how they may indirectly influence stability via biotic mechanisms. We found that the importance of stability mechanisms varied along the environmental gradient: strong negative species covariance occurred in sites characterized by high precipitation variability, whereas portfolio effects increased in sites with high mean annual precipitation. Instead of questioning whether compensatory dynamics are important in nature, our findings suggest that debate should widen to include several stability mechanisms and how these mechanisms vary in importance across environmental gradients.

Original languageEnglish (US)
Pages (from-to)1693-1700
Number of pages8
Issue number6
StatePublished - Jun 2014


  • Compensatory dynamics
  • Dominant species
  • LTER
  • Mean-variance scaling
  • Negative covariance
  • Portfolio effect
  • Taylor's power law

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


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