Patterns, localized structures and fronts in a reduced model of clonal plant growth

TL;DR

This paper develops and analyzes a simplified model of clonal plant growth, revealing how spatial structures and fronts form and transition, with implications for understanding vegetation patterns.

Contribution

It introduces a reduced, spatially explicit model capturing pattern formation and front dynamics in clonal plant systems, including nonlocal and local feedback mechanisms.

Findings

Both model versions exhibit similar pattern formation behavior.

Localized structures organize within snaking bifurcation diagrams.

Transitions between pushed and pulled fronts are characterized and validated.

Abstract

A simplified model of clonal plant growth is formulated, motivated by observations of spatial structures in Posidonia oceanica meadows in the Mediterranean Sea. Two levels of approximation are considered for the scale-dependent feedback terms. Both take into account mortality and clonal, or vegetative, growth as well as competition and facilitation, but the first version is nonlocal in space while the second is local. Study of the two versions of the model in the one-dimensional case reveals that both cases exhibit qualitatively similar behavior (but quantitative differences) and describe the competition between three spatially extended states, the bare soil state, the populated state, and a pattern state, and the associated spatially localized structures. The latter are of two types, holes in the populated state and vegetation patches on bare ground, and are organized within distinct snaking bifurcation diagrams. Fronts between the three extended states are studied and a transition between pushed and pulled fronts identified. Numerical simulations in one spatial dimension are used to determine front speeds and confront the predictions from the marginal stability condition for pulled fronts.