Climate-induced transition in dryland vegetation patterns in presence of grazing

Drylands are pattern-forming systems with multiple stable states and self-organized vegetation patchiness. In this study, we incorporate the impact of grazing in the simplified Gilad-Meron model and compare the effects of linear grazing and livestock grazing on pattern formation. Impacts of climate change on vegetation patterns are reported. Hysteresis behavior is observed in the model depending on climate factors precipitation rate and evaporation rate. Tipping points are identified at which regime shift can occur. Conditions for transcritical bifurcation, saddle–node bifurcation, and direction of Hopf bifurcation are derived analytically for the temporal system. Weak nonlinear analysis is done to predict analytically stripe, hexagonal spot and mixture patterns near the Turing threshold. Desertification can occur when transition from patterned vegetation state to bare soil state due to droughts or other disturbances. It is shown that a transition from a uniform vegetated state to desert state through fairy-circular gap, labyrinth, and hexagonal spot patterns due to Turing and Hopf-Turing instability with the variation of climate conditions. This study re-established the fact that livestock grazing is dangerous for the survival of dryland vegetation compare to linear grazing. Therefore, controlled livestock grazing is necessary for the conservation of dryland biodiversity. It is observed that non-homogeneous livestock grazing is better than homogeneous livestock grazing for long-term survival of vegetation in a real-world ecosystem.