Modeling initial Neolithic dispersal. The first agricultural groups in West Mediterranean

Socio-Ecological Contingencies with Climate Changes over the Prehistory in the Mediterranean Iberia

We conducted palynological, sedimentological, and chronological analyses of a coastal sediment sequence to investigate landscape evolution and agropastoral practices in the Nao Cap region (Spain, Western Mediterranean) since the Holocene. The results allowed for a reconstruction of vegetation, fire, and erosion dynamics in the area, implicating the role of fire in vegetation turnover at 5300 (mesophilous forests replaced by sclerophyllous scrubs) and at 3200 calibrated before present (cal. BP) (more xerophytics). Cereal cultivation was apparent from the beginning of the record, during the Mid-Neolithic period. From 5300 to 3800 cal. BP, long-lasting soil erosion was associated with the presence of cereals, indicating intense land-use during the Chalcolithic and Bronze Age periods. The decline of the agriculture signal and vegetal recolonization is likely explained by land abandonment during the Final Bronze Age. Anthropogenic markers reappeared during the Iberian period when more settlements were present. A contingency of human and environmental agencies was found at 5900, 4200, and 2800 cal. BP, coinciding with abrupt climate events, that have manifested locally in reduced spring discharge, an absence of agropastoral evidence, and a marked decline in settlement densities. This case study, covering five millennia and three climate events, highlights how past climate changes have affected human activities, and also shows that people repeatedly reoccupied the coast once the perturbation was gone. The littoral zone remained attractive for prehistoric communities despite the costs of living in an area exposed to climatic hazards, such as droughts.

Early Neolithic (ca. 5850-4500 cal BC) agricultural diffusion in the Western Mediterranean: An update of archaeobotanical data in SW France

Farming economy was first introduced to the coastal areas of Southern France by Impressa groups (ca. 5850-5650 cal BC), originating from Italy, and subsequently spread to the hinterland by Cardial/Epicardial communities (ca. 5400-4500 cal BC). Fruit and seed remains preserved in archaeological sites provide direct evidence of the botanical resources cultivated and collected by these ancient social groups. But the transition from hunter-gathering to agricultural subsistence strategies is still poorly known in the area, due to insufficient and sometimes outdated archaeobotanical studies. Here we present new results and a critical review of all the available archaeobotanical data, in order to characterize food plant resources, cultivation practices and their variations in time and space. The archaeological dataset is composed of 19 sites (20 site/phases) mostly located in the Mediterranean lowlands. Our results demonstrate that farming economy of the Impressa groups was focused on the cultivation of hulled wheats, with only slight differences compared to their South Italian origins. The contribution of naked cereals increased in the Cardial/Epicardial agriculture, in agreement with the situation in other areas of the Western Mediterranean. The subsistence economy of hinterland sites seems to include a wider contribution of wild fruits and more limited contribution of crops. However, the poor evidence of cultivation activities in the hinterland is likely due first to the difficulties to find and excavate the sites and perform large-scale archaeobotanical sampling. It is likely that agriculture played a significant but variable role between sites and territories.

Modeling the role of voyaging in the coastal spread of the Early Neolithic in the West Mediterranean

The earliest dates for the West Mediterranean Neolithic indicate that it expanded across 2,500 km in about 300 y. Such a fast spread is held to be mainly due to a demic process driven by dispersal along coastal routes. Here, we model the Neolithic spread in the region by focusing on the role of voyaging to understand better the core elements that produced the observed pattern of dates. We also explore the effect of cultural interaction with Mesolithic populations living along the coast. The simulation study shows that (i) sea travel is required to obtain reasonable predictions, with a minimum sea-travel range of 300 km per generation; (ii) leapfrog coastal dispersals yield the best results (quantitatively and qualitatively); and (iii) interaction with Mesolithic people can assist the spread, but long-range voyaging is still needed to explain the archaeological pattern.

Modelling the Geographical Origin of Rice Cultivation in Asia Using the Rice Archaeological Database

We have compiled an extensive database of archaeological evidence for rice across Asia, including 400 sites from mainland East Asia, Southeast Asia and South Asia. This dataset is used to compare several models for the geographical origins of rice cultivation and infer the most likely region(s) for its origins and subsequent outward diffusion. The approach is based on regression modelling wherein goodness of fit is obtained from power law quantile regressions of the archaeologically inferred age versus a least-cost distance from the putative origin(s). The Fast Marching method is used to estimate the least-cost distances based on simple geographical features. The origin region that best fits the archaeobotanical data is also compared to other hypothetical geographical origins derived from the literature, including from genetics, archaeology and historical linguistics. The model that best fits all available archaeological evidence is a dual origin model with two centres for the cultivation and dispersal of rice focused on the Middle Yangtze and the Lower Yangtze valleys.