A topographic mechanism for arcing of dryland vegetation bands. Issue 147 (10th October 2018)

• Record Type: Journal Article
• Authors: Gandhi, Punit; Werner, Lucien; Iams, Sarah; Gowda, Karna; Silber, Mary
• Is Part Of: Journal of the Royal Society interface. Volume 15:Issue 147(2018)
• Publication Date: 2018-10-10
• Subjects: pattern formation -- vegetation patterns -- dryland ecology -- early warning signs -- spatial ecology -- reaction–advection–diffusion; Physical sciences -- Research -- Periodicals; Life sciences -- Research -- Periodicals; Interdisciplinary research -- Periodicals; 570.5
• DOI: 10.1098/rsif.2018.0508
• Languages: English
• ISSNs: 1742-5689

Abstract

Abstract : Banded patterns consisting of alternating bare soil and dense vegetation have been observed in water-limited ecosystems across the globe, often appearing along gently sloped terrain with the stripes aligned transverse to the elevation gradient. In many cases, these vegetation bands are arced, with field observations suggesting a link between the orientation of arcing relative to the grade and the curvature of the underlying terrain. We modify the water transport in the Klausmeier model of water–biomass interactions, originally posed on a uniform hillslope, to qualitatively capture the influence of terrain curvature on the vegetation patterns. Numerical simulations of this modified model indicate that the vegetation bands arc convex-downslope when growing on top of a ridge, and convex-upslope when growing in a valley. This behaviour is consistent with observations from remote sensing data that we present here. Model simulations show further that whether bands grow on ridges, valleys or both depends on the precipitation level. A survey of three banded vegetation sites, each with a different aridity level, indicates qualitatively similar behaviour.