Holocene vegetation change and fire–plant diversity shifts in Mediterranean France

Abstract

Changes in fire activity are recognized as a major threat to biodiversity and vegetation communities across the Mediterranean Basin. However, long‐term fire–vegetation interactions remain poorly investigated. Here, we combine a high‐resolution charcoal record with pollen data from the “ Étang des Aulnes ” lake (southern France) to reconstruct the last ~8000 years of fire dynamics and assess its influence on vegetation communities and diversity. A significant result is that the highest level of fire frequency and burned biomass occurred around 4200 cal a BP , coinciding with the decline of deciduous oak forests and their replacement by evergreen oak forests/scrublands. Moreover, the relationship between taxonomic richness and burned biomass is assessed and shows that taxonomic richness reaches its maximum at intermediate burned biomass levels. We discuss here how fire may explain this relationship, as well as its limitations, which are influenced by variations in environmental and land‐use conditions. Together, these findings illustrate how long‐term fire dynamics influence vegetation diversity and community trajectories and highlight the structuring role of interacting drivers, such as fire, herbivory, and anthropogenic activities, in Mediterranean ecosystems.

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