Evidence for declines in human population densities during the early Upper Paleolithic in western Europe

Abstract

In western Europe, the Middle to Upper Paleolithic (M/UP) transition, dated between Ϸ35,000 and Ϸ40,000 radiocarbon years, corresponded to a period of major human biological and cultural changes. However, information on human population densities is scarce for that period. New faunal data from the high-resolution record of Saint-Cé saire, France, indicate an episode of significant climatic deterioration during the early Upper Paleolithic (EUP), which also was associated with a reduction in mammalian species diversity. High correlations between ethnographic data and mammalian species diversity suggest that this shift decreased human population densities. Reliance on reindeer (Rangifer tarandus), a highly fluctuating resource, would also have promoted declines in human population densities. These data suggest that the EUP represented for humans a period of significant niche contraction in western Europe. In this context, the possibility that a modern human expansion occurred in this region seems low. Instead, it is suggested that population bottlenecks, genetic drift, and gene flow prevailed over human population replacement as mechanisms of evolution in humans during the EUP.archaeology ͉ Rangifer ͉ Middle to Upper Paleolithic transition ͉ modern human origins ͉ Neandertals

Climate and Demography in Early Prehistory: Using Calibrated14C Dates as Population Proxies

“…In addition, the summed probability distribution frequencies of the calibrated radiocarbon dates decline steeply simultaneously with a similar decline in the reindeer population in the region at the Older Dryas/GI-1d transition (Aaris-Sørensen et al 2007) (Figure 8). Morin (2008) has recently shown that Rangifer herd sizes in historical times fl uctuated in largely unpredictable cycles and that the fl uctuations were Although these values may not be directly comparable to those plotted in Figure 1, faunal diversity is shown to significantly decline with latitude (r s 0.56, p  0.01), despite the large climatic fl uctuations spanned by these sites. The extremely low diversity values in the northernmost sites are noteworthy.…”

“…Although a lack of quantitative demographic data for these forager groups makes the link between prey herd size and human population densities ultimately dependent on oral and anecdotal histories, reasonable quantitative demographic data on other high-latitude hunter-gatherers are available (e.g., Constandse-Westermann 1993;Robert-Lamblin 2006). In general, hunter-gatherers are strongly dependent on key resources, and their demographic fate tracks that of their primary prey (Morin 2008;Stenton 1991) (Figure 1). Importantly, these fl uctuations are not merely seasonal, nor are they caused by hunting pressure exerted by humans (Aanes et al 2000;Kojola 2006, 2008).…”

“…Importantly, these fl uctuations are not merely seasonal, nor are they caused by hunting pressure exerted by humans (Aanes et al 2000;Kojola 2006, 2008). They are effectively unpredictable and become larger as climate deteriorates (Morin 2008). Times of economic or ecological adversity are associated with increased mortality and lowered population densities, even given the relatively moderate climatic changes of the recent past.…”

“…There is a strong (Spearman's rank) correlation between mammalian species diversity and forager population density in this data set: r s  0.62, p  0.002, for the whole data set; r s  0.82, p  0.001, for cold/open country groups; r s  0.81, p  0.07, for temperate grassland groups. Data from Morin (2008). Linear fi t lines have been added for the whole data set (dashed line), the cold/open country groups (dotted line), and the temperate/northern forested groups (solid line).…”

Mitochondrial diversity patterns and the Magdalenian resettlement of Europe: new insights from the edge of the Franco-Cantabrian refuge

“…It is known that human population size in Europe declined from the beginning of the Upper Paleolithic until the Bølling-Allerød interstadial, because of a dietary breadth contraction caused by prey extinction. 15 A likely effect of this would have been an enhancement of genetic drift coupled with recurrent population bottlenecks, which are the major factors in the shaping of genetic diversity. 16 During the Last Glacial Maximum, conditions would have been worsened, as paleoecological modeling has shown the maximum range of the glacial refuges to be small and constrained by permafrost areas.…”