Dynamic Coupling of Infiltration-Soil Moisture Feedback:Emergent Vegetation Patterns in a Water-Vegetation Model

TL;DR

This paper develops a water-vegetation model to understand how infiltration-soil moisture feedback influences vegetation pattern formation and ecosystem state transitions in arid environments.

Contribution

It introduces a modified model combining Turing pattern theory and bifurcation analysis to explain nonlinear vegetation dynamics and regime shifts.

Findings

Multiple stable ecological states identified.

Existence of Turing-Hopf bifurcation in the system.

Soil moisture feedback controls ecosystem state transitions.

Abstract

We present a modified water-vegetation model to investigate the mechanistic relationship between infiltration-soil moisture feedback and vegetation pattern in arid/semi-arid ecosystems. Employing Turing pattern formation theory, we drive conditions for diffusion-induced instability and analyze spatiotemporal dynamics near Turing-Hopf bifurcation points. Our key findings include: (i) The system exhibits rich dynamics including multiple stable equilibria, supercritical/subcritical Hopf bifurcations, bubble loops of limit cycles and homoclinic bifurcations. (ii) The system admits Turing-Hopf bifurcation. Using normal form theory, we establish the existence of quasiperiodic solutions and mixedmode oscillations near critical thresholds, providing a mathematical framework for predicting nonlinear ecological regime shifts. (iii) Soil moisture feedbacks govern critical transitions between three distinct ecosystem states: uniform vegetation covering, self-organized spatial patterns (labyrinth/gapped vegetation), and bare soil state, which demonstrates that soil moisture thresholds control the final state selection in this system.