Historical range of fire frequency is not the Achilles' heel of the Corsican black pine ecosystem

This study investigated the fire‐vegetation relationship by reconstructing the long‐term fire and vegetation dynamics around a small lake in the Mediterranean montane belt on Corsica Island. The vegetation is characterised by forests dominated by Pinus nigra ssp. laricio, an endemic subspecies that is currently threatened. Populations of this taxon are geographically restricted, and their ranges are decreasing, possibly because of disturbance, that is, fire and logging. Here, we examine the role of fire in vegetation dynamics and its effect on diversity since the lateglacial at a montane site using sedimentary plant macrofossils and charcoal to reconstruct local vegetation and fire frequency, respectively. Macrofossils of P. laricio provide evidence for its growth around the Lac de Creno since 13 200 cal. years bp, which is consistent with its natural origin in Corsica. The onset of the Holocene (~11 700 cal. years bp) was marked by a rapid shift in the treeline, the establishment of P. laricio‐dominated woodlands with low species turnover, and a long‐term increase in taxa richness as a result of successive expansions of broadleaved deciduous trees. In spite of fire‐return intervals (FRIs) fluctuating between 30 and 490 years during the Holocene, P. laricio‐dominated woodlands persisted for several millennia, and fires likely played an ecological role in the functioning of these woodlands. The 12 000 year record of mean FRI (80 years between fires; i.e. frequency of 12.5 fires 1000 year⁻¹) can be used to define a baseline for the management and conservation of P. laricio montane forests. Our findings demonstrate that P. laricio has a long history, a natural origin in Corsica, and that Corsican pine forests have survived to a wide range of burning conditions over the last 13 200 years. Synthesis: We present multimillennial fire and vegetation histories of a Mediterranean montane site. Pinus nigra ssp. laricio has been present near the study site since approximately 13 200 cal. years bp, demonstrating that this pine was present on the island prior to the arrival of pre‐historic humans. The long‐term records also show that P. laricio woodlands were mixed with deciduous broadleaf trees (Betula sp. and Fagus sylvatica), and other needleleaf trees (Abies alba), at least, and were not influenced by changes in fire frequency. We conclude that (i) fire is a natural component of the ecosystem and (ii) fires likely played an important ecological role in the functioning of the Corsican black pine woodland ecosystem.