Dispersal of crop-livestock and geographical-temporal variation of subsistence along the Steppe and Silk Roads across Eurasia in prehistory

The innovations of agricultural production and their extensive dispersal promoted the transformation of human livelihoods and profoundly influenced the evolution of human-land relationships in late prehistoric Eurasia. The Steppe and Silk Roads (SSRs) played important roles in the transcontinental exchange and dispersal of cereal crops and livestock related to agricultural innovation across Eurasia before the Han Dynasty (202 BC to AD 220), while the geographical-temporal variations in prehistoric subsistence in relation to the spread and exchange of cereal crops and livestock originating from different areas of Eurasia still remain unclear. In this paper, we explore these issues based on the review and analysis of published archaeobotanical, zooarchaeological, and carbon-stable isotope data from human bones from Neolithic-Early Iron Age sites in areas along the SSRs, with a comparison to updated results based on radiocarbon dating and ancient DNA analyses. Our results suggest that humans engaged in hunting game, while foxtail/broomcorn millet cultivation gradually became the primary subsistence strategy in Eastern SSRs from 10,500 to 6000 a BP. In contemporaneous Western SSRs, humans mainly cultivated wheat/barley and raised sheep/goats, cattle, and pigs. Trans-Eurasian exchange, which is reflected by the mixed utilization of wheat/barley and millet, emerged in the south-central Steppe during 6000-4000 a BP, while millet cultivation and pig husbandry became the dominant livelihoods in most areas of Eastern SSRs. During 4000-2200 a BP, Silk Roads became the major passageway for trans-Eurasian exchange, the interactive development of oasis agriculture and pastoralism facilitated intensive human settlement in the Central Silk Roads, and subsistence strategies substantially changed with significant geographical differences in Eastern SSRs, while subsistence in some areas of Western SSRs was evidently affected by the introduction and adoption of millet crops after 3000 a BP. The geographical-temporal variations in subsistence in the SSRs from the Neolithic to Early Iron Age were primarily affected by the prehistoric dispersal of farming groups across Eurasia, which was accompanied by the spread of cereal crops/livestock, while the impacts of climate change still need to be further evaluated.

Automated summary

Innovations in agricultural production and the spread of these innovations through the Steppe and Silk Roads had a significant impact on the evolution of human-land relationships in late prehistoric Eurasia. There were variations in subsistence strategies across different regions, with millet cultivation and pig husbandry becoming dominant in the Eastern SSRs, while wheat/barley cultivation and sheep/goat, cattle, and pig raising were prevalent in the Western SSRs. The Trans-Eurasian exchange and the introduction of millet crops also influenced subsistence patterns, particularly in the Central Silk Roads.