Experimental tests of the dependence of arthropod diversity on plant diversity

Evan Siemann, David Tilman, John Haarstad, Mark Ritchie

Research output: Contribution to journalArticlepeer-review

485 Scopus citations


Because a diversity of resources should support a diversity of consumers, most models predict that increasing plant diversity increases animal diversity. We report results of a direct experimental test of the dependence of animal diversity on plant diversity. We sampled arthropods in a well-replicated grassland experiment in which plant species richness and plant functional richness were directly manipulated. In simple regressions, both the number of species planted (log2 transformed) and the number of functional groups planted significantly increased arthropod species richness but not arthropod abundance. However, the number of species planted was the only significant predictor of arthropod species richness when both predictor variables were included in ANOVAs or a MANOVA. Although highly significant, arthropod species richness regressions had low R2 values, high intercepts (24 arthropod species in monocultures), and shallow slopes. Analyses of relations among plants and arthropod trophic groups indicated that herbivore diversity was influenced by plant, parasite, and predator diversity. Furthermore, herbivore diversity was more strongly correlated with parasite and predator diversity than with plant diversity. Together with regression results, this suggests that, although increasing plant diversity significantly increased arthropod diversity, local herbivore diversity is also maintained by, and in turn maintains, a diversity of parasites and predators.

Original languageEnglish (US)
Pages (from-to)738-750
Number of pages13
JournalAmerican Naturalist
Issue number5
StatePublished - 1998
Externally publishedYes


  • Arthropod diversity
  • Grasslands
  • Herbivores
  • Parasites
  • Plant diversity
  • Predators

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


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