The resource economics of chemical and structural defenses across nitrogen supply gradients.

Academic Article


  • In order to better understand the role of nutrient supplies in determining the prevalence of plant defense types, we investigated the theoretical relationships between ecosystem N supply and the net C gain of shoots that were undefended or defended in one of three ways: (1) by N-free chemical compounds, (2) by N-containing chemical compounds, or (3) by structural defenses. By extending economic models of shoot resource balance to include the relative value of C and N, depreciation, and amortization, we were able to show that the relative net C gain of the three defense types were similar to changes in their generally understood abundance along an N supply gradient. At low N supply, the additional C acquired when investing C in defense is much higher than investing N in defenses. Only at high N supply is it better to invest large quantities of N in defense rather than additional photosynthesis. In a sensitivity analysis, net C gain of shoots was most sensitive to factors that affect the relative value of C and N and the rate of herbivory. Although there is support for the relative value of C and N influencing defense strategies, more research is necessary to understand why tannins are not more prevalent at high N supply and why moderate amounts of N-based defenses are not used at low N supply.
  • Authors

  • Craine, Joseph
  • Bond, William
  • Lee, William G
  • Reich, Peter B
  • Ollinger, Scott
  • Status

    Publication Date

  • December 2003
  • Published In

  • Oecologia  Journal
  • Keywords

  • Adaptation, Physiological
  • Animals
  • Carbon
  • Ecosystem
  • Insecta
  • Nitrogen
  • Plant Development
  • Plants
  • Plants, Edible
  • Tannins
  • Digital Object Identifier (doi)

    Pubmed Id

  • 13680348
  • Start Page

  • 547
  • End Page

  • 556
  • Volume

  • 137
  • Issue

  • 4