Impacts of shrub encroachment on ecosystem structure and functioning

Towards a global synthesis

David J. Eldridge, Matthew A Bowker, Fernando T. Maestre, Erin Roger, James F. Reynolds, Walter G. Whitford

Research output: Contribution to journalArticle

459 Citations (Scopus)

Abstract

Encroachment of woody plants into grasslands has generated considerable interest among ecologists. Syntheses of encroachment effects on ecosystem processes have been limited in extent and confined largely to pastoral land uses or particular geographical regions. We used univariate analyses, meta-analysis and structural equation modelling to test the propositions that (1) shrub encroachment does not necessarily lead to declines in ecosystem functions and (2) shrub traits influence the functional outcome of encroachment. Analyses of 43 ecosystem attributes from 244 case studies worldwide showed that some attributes consistently increased with encroachment (e.g. soil C, N), and others declined (e.g. grass cover, pH), but most exhibited variable responses. Traits of shrubs were associated with significant, though weak, structural and functional outcomes of encroachment. Our review revealed that encroachment had mixed effects on ecosystem structure and functioning at global scales, and that shrub traits influence the functional outcome of encroachment. Thus, a simple designation of encroachment as a process leading to functionally, structurally or contextually degraded ecosystems is not supported by a critical analysis of existing literature. Our results highlight that the commonly established link between shrub encroachment and degradation is not universal.

Original languageEnglish (US)
Pages (from-to)709-722
Number of pages14
JournalEcology Letters
Volume14
Issue number7
DOIs
StatePublished - Jul 2011

Fingerprint

ecosystem structure
shrub
shrubs
synthesis
ecosystems
ecosystem
critical analysis
geographical region
meta-analysis
woody plant
ecosystem function
ecologists
woody plants
land use
grasslands
grassland
grass
case studies
grasses
degradation

Keywords

  • Degradation
  • Desertification
  • Ecosystem processes
  • Encroachment
  • Invasion
  • Shrub
  • Shrubland
  • Thickening
  • Woody

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

Cite this

Impacts of shrub encroachment on ecosystem structure and functioning : Towards a global synthesis. / Eldridge, David J.; Bowker, Matthew A; Maestre, Fernando T.; Roger, Erin; Reynolds, James F.; Whitford, Walter G.

In: Ecology Letters, Vol. 14, No. 7, 07.2011, p. 709-722.

Research output: Contribution to journalArticle

Eldridge, David J. ; Bowker, Matthew A ; Maestre, Fernando T. ; Roger, Erin ; Reynolds, James F. ; Whitford, Walter G. / Impacts of shrub encroachment on ecosystem structure and functioning : Towards a global synthesis. In: Ecology Letters. 2011 ; Vol. 14, No. 7. pp. 709-722.
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