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Published October 2018 | public
Journal Article

A topographic mechanism for arcing of dryland vegetation bands

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.

Additional Information

© 2018 The Author(s) Published by the Royal Society. Received: 5 July 2018; Accepted: 12 September 2018; Published 10 October 2018. Data accessibility: All data are publicly available [11,28,29,35,38,39]. Authors' contributions: P.G. conceived the modelling approach, carried out the numerical simulations and took the lead in drafting the manuscript. All authors participated in the data analysis and interpretation, contributed to the writing of the manuscript and gave final approval for publication. We declare we have no competing interests. This work was supported in part by the National Science Foundation grant no. DMS-1440386 to the Mathematical Biosciences Institute (P.G.), National Science Foundation grants DMS-1517416 (M.S.) and DMS-1547394 (K.G.) and the James S. McDonnell Foundation (K.G.). We are grateful to Justin Finkel for helpful discussions.

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023