Tree-grass interactions in Savannas

R. J. Scholes, Steve Archer

Research output: Contribution to journalArticle

1564 Citations (Scopus)

Abstract

Savannas occur where trees and grasses interact to create a biome that is neither grassland nor forest. Woody and gramineous plants interact by many mechanisms, some negative (competition) and some positive (facilitation). The strength and sign of the interaction varies in both time and space, allowing a rich array of possible outcomes but no universal predictive model. Simple models of coexistence of trees and grasses, based on separation in rooting depth, are theoretically and experimentally inadequate. Explanation of the widely observed increase in tree biomass following introduction of commercial ranching into savannas requires inclusion of interactions among browsers, grazers, and fires, and their effects on tree recruitment. Prediction of the consequences of manipulating tree biomass through clearing further requires an understanding of how trees modify light, water, and nutrient environments of grasses. Understanding the nature of coexistence between trees and grass, which under other circumstances are mutually exclusive or unequal partners, yields theoretical insights and has practical implications.

Original languageEnglish (US)
Pages (from-to)517-544
Number of pages28
JournalAnnual Review of Ecology and Systematics
Volume28
DOIs
StatePublished - 1997
Externally publishedYes

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savanna
savannas
grass
grasses
coexistence
ranching
biomass
facilitation
biome
rooting
space and time
grasslands
grassland
prediction
ecosystems
nutrient
nutrients
water

Keywords

  • Competition
  • Facilitation
  • Fire
  • Herbivory
  • Stability

ASJC Scopus subject areas

  • Ecology

Cite this

Tree-grass interactions in Savannas. / Scholes, R. J.; Archer, Steve.

In: Annual Review of Ecology and Systematics, Vol. 28, 1997, p. 517-544.

Research output: Contribution to journalArticle

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