Spatial Trophic Dynamics Shape and are Shaped by Desertification Transitions

Abstract

Drylands, which sustain billions of people, face desertification driven by climate change and grazing pressures. From the bottom up, desertification is affected by water availability, with vegetation often self-organising into spatial patterns that vary with aridity levels. How these patterns and ultimately, desertification transitions, are affected by the spatial dynamics of higher trophic levels remain, however, poorly understood. Here, we introduce a spatially explicit tri-trophic model that links vegetation pattern formation to consumer-resource interactions and foraging behaviour. We find that the nature of vegetation spatial distribution and desertification transition strongly influence consumer spatial organisation, movement, and synchrony. Vegetation organised regularly in space generates "boom--bust" synchronised metapopulations, whereas fractal vegetation organisation generates scale-free consumer clustering and low synchrony. Our results reveal a reciprocal coupling between spatial trophic dynamics and ecosystem resilience, underscoring the need to integrate trophic interactions and behaviour into predictions informing management strategies for dryland ecosystems.