Spatiotemporal Dynamics: Applications to vegetation population dynamics

Abstract

Vegetation patterns appear in a wide range of ecosystems like drylands, salt marshes or seagrass meadows, forming a large variety of structures like patches of vegetation, fairy circles or vegetation labyrinths. The mechanisms behind the formation of these structures are still a matter of discussion. Our focus is to investigate the origin of a pattern formed by arcs of bare soil in a homogeneous meadow of Posidonia Oceanica observed in the Pollen¸ca bay (Mallorca). Similar spatial structures emerge from excitable dynamics between vegetation density and sulfide concentration in the soil, like ring-shaped pulses of vegetation propagating through the seabed, as reported by Ruiz-Reyn´es et al. Here we use bifurcation theory and stability analysis to examine whether these structures could be originated by the same process. The theoretical model used successfully predicts an alternative excitable regime where vegetation transiently disappears before returning to the homogeneous state, which should be compatible with the pattern of arcs mentioned