How complex is the evolution of small mammal communities during the Late Glacial in southwest France?

The Late Glacial was a slow gradual warming associated with short, cold events that occurred between 18.0 and 11.7 ka cal. BP. Pollen analyses from deep-sea and lacustrine cores have well documented the evolution of floral communities in western Europe and suggest that climatic fluctuations influenced the evolution of terrestrial ecosystems. However, the exact impact of these climate changes on small faunal communities in southwest France is still poorly documented. Peyrazet Cave is an archaeological site located in the Lot (France) that has been excavated since 2008 and has yielded a Late Glacial sequence dated between 15.5 and 11.1 ka cal. BP. Thousands of small faunal remains resulting from a natural accumulation have been recovered. Investigation of this material has surprisingly revealed remains of two rodents that currently inhabit Central and Eastern Europe, the northern birch mouse (Sicista betulina) and the European hamster (Cricetus cricetus). The presence of these two taxa, which had migrated from the east and had been never documented in this region before the Late Glacial, is most likely related to short climatic fluctuations in the Late Glacial, suggesting more complex scenarios than traditionally accepted to explain the evolution of small faunal communities between the Last Glacial Maximum and the Holocene.