Existence of localised radial patterns in a model for dryland vegetation

Abstract

Localised radial patterns have been observed in the vegetation of semi-arid ecosystems, often as localised patches of vegetation or in the form of `fairy circles'. We consider stationary localised radial solutions to a reduced model for dryland vegetation on flat terrain. By considering certain prototypical pattern-forming systems, we prove the existence of three classes of localised radial patterns bifurcating from a Turing instability. We also present evidence for the existence of localised gap solutions close to a homogeneous instability. Additionally, we numerically solve the vegetation model and explore the bifurcation structure and stability of localised radial spots and gaps. We conclude by investigating the effect of varying certain parameter values on the existence and stability of these localised radial patterns.