Middle to late Holocene human societies on the eastern margin of the Eurasian Steppe, and their adaptation to environmental changes

The impact of environmental changes on the development of human societies in the Eurasian Steppe is not well understood over the Holocene timescale. In this study, we have reported the phytoliths, grain size, and weight loss on ignition for an aeolian soil profile in the Liao River Basin at the eastern margin of the Eurasian Steppe. The profiles spanned the middle and late Holocene based on AMS 14C dating. By employing the summed radiocarbon probability distribution of archaeological sites and kernel density analysis, the spatial and temporal distributions of human populations and settlements were investigated in order to analyze the rise and fall of ancient cultures. Our findings indicated that the environment in the Liao River Basin underwent three stages of change. From 6700 to 5400 cal yr BP, the climate was warm and humid. The climate suddenly became cold and dry from 5400 to 4900 cal yr BP. The climate fluctuated, with a general tendency towards cold and dry conditions, from 4900 cal yr BP to 1700 cal yr BP. In addition, human societies in the region underwent significant changes, with rapid agricultural development and population growth in the warm and humid environment of the Middle Neolithic (6700-5000 yr BP). However, during the Late Neolithic (5000-4000 yr BP), the living environment suddenly became cold and dry, which limited the development of human society and drastically reduced its population. Nevertheless, the resilience of human societies continued to increase, and in the Bronze Age (4000-2000 yr BP), even in an overall cold and dry living environment, human societies still developed and their population increased sharply. Changes in the East Asia Summer Monsoon were an important driver of cultural change, and our study emphasizes the complex human-environment interactions that shaped societal development on the Eurasian Steppe.