Fire and Herbivory as Architects of Mediterranean Biodiversity

The Mediterranean region hosts exceptional biodiversity shaped by millennia of interactions between climate, and disturbances: both fire and herbivores. This study reconstructs 8000 yrs of habitats combustibility and herbivores (domestic and wild) dynamics in the Crau Plain using paleoecological records.

Richness, evenness and turnover of vegetation dynamics were calculated to tackle the interconnexion with herbivores dynamics. Our results demonstrate a strong positive correlation between herbivores (indicated by coprophilous fungal spores) and palynological richness, determining the role of grazing by both wild and domesticated herbivores in maintaining ecological heterogeneity. The decline in grazing during the past millennium has coincided with an increase in woody vegetation, posing heightened fire risks under current climate change scenarios.

On the other hand, the palynological records has been converted into habitats and their relative combustibility. Early periods (7200–3900 cal. BP) exhibited lower habitat diversity dominated by less combustible vegetation correlated with cooler and wetter climate. However, from 3900 cal. BP, increased pastoralism and fire activity fostered the expansion of grasslands and fire-prone ecosystems.

By linking long-term ecological dynamics with modern conservation challenges, this study underscores the importance of integrating grazing management and fire regulation into biodiversity conservation strategies to sustain Mediterranean landscape resilience.