Intraspecific variation and species coexistence

Jeremy W. Lichstein, Jonathan Dushoff, Simon Asher Levin, Stephen Wilson Pacala

Research output: Contribution to journalArticle

55 Scopus citations

Abstract

We use a two-species model of plant competition to explore the effect of intraspecific variation on community dynamics. The competitive ability ("performance") of each individual is assigned by an independent random draw from a species-specific probability distribution. If the density of individuals competing for open space is high (e.g., because fecundity is high), species with high maximum (or large variance in) performance are favored, while if density is low, species with high typical (e.g., mean) performance are favored. If there is an interspecific mean-variance performance trade-off, stable coexistence can occur across a limited range of intermediate densities, but the stabilizing effect of this trade-off appears to be weak. In the absence of this trade-off, one species is superior. In this case, intraspecific variation can blur interspecific differences (i.e., shift the dynamics toward what would be expected in the neutral case), but the strength of this effect diminishes as competitor density increases. If density is sufficiently high, the inferior species is driven to extinction just as rapidly as in the case where there is no overlap in performance between species. Intraspecific variation can facilitate coexistence, but this may be relatively unimportant in maintaining diversity in most real communities.

Original languageEnglish (US)
Pages (from-to)807-818
Number of pages12
JournalAmerican Naturalist
Volume170
Issue number6
DOIs
StatePublished - Dec 10 2007

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics

Keywords

  • Coexistence
  • Competition
  • Drift
  • Individual variation
  • Neutral theory
  • Trade-off

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