Impacts of shrub encroachment on ecosystem structure and functioning: towards a global synthesis.

Published

Journal Article (Review)

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.

Full Text

Duke Authors

Cited Authors

  • Eldridge, DJ; Bowker, MA; Maestre, FT; Roger, E; Reynolds, JF; Whitford, WG

Published Date

  • July 2011

Published In

Volume / Issue

  • 14 / 7

Start / End Page

  • 709 - 722

PubMed ID

  • 21592276

Pubmed Central ID

  • 21592276

Electronic International Standard Serial Number (EISSN)

  • 1461-0248

International Standard Serial Number (ISSN)

  • 1461-023X

Digital Object Identifier (DOI)

  • 10.1111/j.1461-0248.2011.01630.x

Language

  • eng