Ungulate biomass fluctuations endured by Middle and Early Upper Paleolithic societies (SW France, MIS 5-3): The contributions of modern analogs and cave hyena paleodemography

From MIS 5 to 3, Western Europe has seen important climate changes that shaped the environments inhabited by past human societies. As a consequence, climate is often considered as a key factor in explaining the cultural and biological events of the Middle and Early Upper Paleolithic (e.g. changes in lithic technology and mobility strategies during the Mousterian, Neanderthal extinction, emergence of “modern” behavior, onset of the Upper Paleolithic). However, the exact impact of Upper Pleistocene global climatic changes on terrestrial ecosystems is still poorly documented. Remarkably, large predators can be affected by changes in herbivore communities because they result in fluctuations of the ecosystem's carrying capacity. Paleoenvironmental reconstructions that include data on faunal dynamics are still rare, so that questions concerning human–environment interactions cannot be properly discussed.Building on a review of modern analogs for ungulate biomass, this paper tries to reconstruct changes in carrying capacity of terrestrial ecosystems in southwestern France. In order to assess the importance of these biomass fluctuations for large predators, cave hyena paleodemographic shifts are estimated through Bayesian analyses of the chronological distribution of hyena den assemblages. Comparison between these two proxies (ungulate biomass modern analogs and cave hyena paleodemography) allows for an adequate discussion of the impact of ungulate biomass fluctuations on large predators.Results show that fluctuations in ungulate biomass are noticeable, with an increase at the end of the Mousterian and a significant drop at the beginning of the Aurignacian. These changes likely had a pronounced impact on large predator populations, as interesting parallels can be identified between the demographic history of hyenas and reconstructed fluctuations in carrying capacity. These results bring new insights on the role played by MIS 3 environmental changes in the demise of the last Neanderthals and the emergence of the Upper Paleolithic in southwestern France.