Biogenic crust dynamics on sand dunes

TL;DR

This paper investigates how biogenic crusts influence sand dune stability and dynamics, revealing two stable states and a potential transition related to desertification processes.

Contribution

It introduces a simple model to analyze the stability of crusted and vegetated dunes across rainfall and wind conditions, highlighting their roles in dune dynamics.

Findings

Identifies two ranges of stable dune states: crusted and vegetated at low wind power.

Reveals a transition between stable vegetated dunes and active dunes at high wind power.

Suggests a link between biogenic crusts and desertification processes.

Abstract

Sand dunes are often covered by vegetation and biogenic crusts. Despite their significant role in dune stabilization, biogenic crusts have rarely been considered in studies of dune dynamics. Using a simple model, we study the existence and stability ranges of different dune-cover states along gradients of rainfall and wind power. Two ranges of alternative stable states are identified: fixed crusted dunes and fixed vegetated dunes at low wind power, and fixed vegetated dunes and active dunes at high wind power. These results suggest a cross-over between two different forms of desertification.