Microtopography alters self-organized vegetation patterns in water-limited ecosystems

Gavan S. McGrath, Kyungrock Paik, Christoph Hinz

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

In terrestrial systems limited by water availability the spatial distribution of vegetation can self-organize into a mosaic of vegetated patches and bare soil. Spatially extensive competition for water and short-range facilitation underpin many models that describe the process of vegetation pattern formation. Earlier studies investigating this self-organized patchiness have largely considered smooth landscapes. However, topographic variations can significantly alter the redistribution of surface water flow and therefore the pattern-forming process. Here, we consider how microtopographic variations, at the scale of individual plants, alters self-organized vegetation patterns with the use of a simple ecohydrological model. We show that increasing microtopography can induce a change from banded vegetation, oriented across the slope, to irregular drainage patterns, oriented in the downslope direction. The mechanism responsible is shown to be a change in the spatial redistribution of infiltration around plants and plant patches. Only small increases in microtopography are required to cause banded systems with weak facilitation to change to downslope-oriented patterns. When non-periodic boundary conditions were considered, band orientation tended to become oblique to the topographic contour and in some circumstances their migration upslope ceased. These results suggest that diffusive sediment transport processes may be essential for the maintenance of regular periodic vegetation patterns, which implies that erosion may be critical for understanding the susceptibility of these ecosystems to catastrophic shifts.

Original languageEnglish
Article numberG03021
JournalJournal of Geophysical Research: Biogeosciences
Volume117
Issue number3
DOIs
Publication statusPublished - 2012 Sep 1

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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