Date Published: February 13, 2019
Publisher: Public Library of Science
Author(s): Isabell Schmidt, Andreas Zimmermann, Peter F. Biehl.
Demographic estimates are presented for the Aurignacian techno-complex (~42,000 to 33,000 y calBP) and discussed in the context of socio-spatial organization of hunter-gatherer populations. Results of the analytical approach applied estimate a mean of 1,500 persons (upper limit: 3,300; lower limit: 800) for western and central Europe. The temporal and spatial analysis indicates an increase of the population during the Aurignacian as well as marked regional differences in population size and density. Demographic increase and patterns of socio-spatial organization continue during the subsequent early Gravettian period. We introduce the concept of Core Areas and Extended Areas as informed analytical spatial scales, which are evaluated against additional chronological and archaeological data. Lithic raw material transport and personal ornaments serve as correlates for human mobility and connectedness in the interpretative framework of this study. Observed regional differences are set in relation with the new demographic data. Our large-scale approach on Aurignacian population dynamics in Europe suggests that past socio-spatial organization followed socially inherent rules to establish and maintain a functioning social network of extremely low population densities. The data suggest that the network was fully established across Europe during the early phase of the Gravettian, when demographic as well as cultural developments peaked.
A key issue in Paleolithic research is the understanding of how demographic, social, technological and environmental factors influenced the successful spread and establishment of anatomically modern Humans across Europe. It is commonly accepted that the Aurignacian techno-complex constitutes a pan-European phenomenon [1, 2]. Its homogeneous archaeological appearance at this scale has favored models considering fast-spreading, highly mobile and interconnected populations. Yet, explanatory models of biological and cultural developments compete on mode and pace. This is commonly due to the poor chronological resolution, limited anthropological evidence, and the ongoing discussion on the internal and regionally heterogeneous chrono-cultural structure of the paleoanthropological and archaeological record itself [3–7].
The defined period under investigation covers the Aurignacian techno-complex in Europe, spanning roughly from 42–33 ky calBP . Paleoclimatically, it comprises the Greenland Interstadials 11 to 6 and Heinrich Event 4, the latter dated to 39.8–37.9 ky calBP . The beginning of the Aurignacian is defined by the onset of the Proto and Early Aurignacian. Assemblages attributed to so-called “transitional” industries of probably Neanderthal or yet unknown origin were not considered in our study, since most of the well dated sequences indicate little or no overlap with the period under study [23, 24]. The end of the Aurignacian and beginning of the Gravettian seem to be regionally differentiated with older dated occurrences found in central and eastern Europe [25–28]. Contested assemblages in southern Iberia have been reclassified as an early Gravettian, based on technological investigations and critical reassessment of the collections . For the purpose at hand, the cultural attribution was weighted more than the overlapping early radiocarbon dates of a few Gravettian sites (Trencianske Bohuslavice-Pod Tureckom, Henrykow 15, Dolni Vestonice IIa, Ranis) which were therefore excluded.
For the Aurignacian of western and central Europe, we estimated a population of 1,500 people, ranging from 900 to 3,800 people (Table 2). The population density estimate (given in people per 100 km2) is 0.103 P/100 km2 for the TAC (1,500,000 km2). 81% of all sites used in our density based approach (245 out of 304) are located within the CAs. In the present study, 13 individual CAs are identified (Table 3, Fig 2: upper). Highest estimated population numbers for the CAs are found in SW France (440 persons), N Spain (260 persons), Belgium (210), the middle Danube/Moravian (170 persons), and the upper Danube area (140 persons). Mean estimates for the remaining CAs range between 10 and 80 persons each (overall mean = 40). This interesting and marked separation of the size of the population estimates into larger (≳140) and smaller ones (<80) will be discussed later in more detail. Within the CAs the overall estimated population density centers around 1.442 P/100 km2. The highest densities are estimated for the CA of Belgium (mean = 3.000 P/100 km2), while the lowest density is reported from the Middle Danube and Krakow area (0.844). The population estimates presented in this study for the TAC (ranging from 0.059–0.254 P/100 km2) are lower than those obtained by other studies; although a methodologically similar approach using site numbers and ethno-historic population densities arrived at a similarly low mean density estimate of 0.168 P/100 km2 for entire Europe (:1664). We argue that this is because the TAC focuses on an area of general high population density. If including reported empty areas—such as Southern Iberia and Britain—our estimates would be reduced considerably in comparison. The same argument holds for diachronic estimates presented for several Upper Paleolithic periods using ethno-historic data and a climate envelope modeling approach : much higher densities, 4.4 P/100 km2, were predicted in a slightly younger period, around 30 ky BP, with highest densities being observed in Iberia. Even at the scale of CAs, our approach does not arrive at such high densities. Both approaches exclude economically uninhabitable areas from calculations, however, they do not consider scaling effects in ethno-historic density data , which were avoided by the present approach using group size data instead. In the same line, we argue that site-distribution patterns, although being subject to frequently discussed biases, must be considered as a source of information on spatial organization too, and settlement intensity should not be averaged across Europe. The new results and data presented and discussed within the previous sections allow for multiple and regionally varying explanatory scenarios, although it is not the scope of this paper to test these hypotheses on regional grounds. As for the large-scale approach of this study, which encompasses the above-defined TAC, we propose a general socio-spatial organization for the Aurignacian that rests upon our finding of successfully established, continuous and viable populations (≥150 persons) being established across Europe and separated by a distance of around 400 km—as the crow flies—from each other (Fig 5: upper). This observation leads us to argue for a “social carrying capacity” of human groups inhabiting a landscape. This social carrying capacity is shaped by cognition and sociality of humans and expected to be expressed in the socio-spatial patterns. This concept clearly differs from its economic namesake, although equifinality or adaptive processes of both social [1, 72] and economic realms could lead to the observable patterns . Exploration of the conceptual and practical distinction between social and economic carrying capacities in the interpretation of large scale archaeological patterns is a worthwhile avenue of further research. Clarification of the repeatedly observed “mismatches” between predicted (based on paleo-environmental and/or ethno-historic data) and observed human presence [18, 12, 14] or of changes in the “attractiveness” of landscapes  could be one of its promising outputs. Source: http://doi.org/10.1371/journal.pone.0211562