Hydro-climatic aspects of prehistoric human dynamics in the drylands of the Asian interior

The causes of prehistoric human migrations in the drylands of the Asian interior have long been debated among multidisciplinary scholars. The Bronze Age Xiaohe settlements (ca. 4000-3300 cal yr BP) are situated in the extremely arid Tarim Basin of northwest China and exemplify a societal collapse which included a long-distance movement along river catchments. Here, we present the results of stable carbon isotope values (delta C-13) of archaeobotanical remains, sedimentary faces analysis from the Tarim River catchment, and a compilation of palaeo-environmental evidence in order to investigate potential relationships between regional environmental changes and the response of prehistoric societies in this arid region. Results suggest that the early Xiaohe population was forced to migrate as a consequence of the deterioration of hydrological conditions around settlements. The decline of Xiaohe Culture occurred in the context of decreasing water availability in the basin interior due to climatic change lasting several hundred years. Results are potentially significant for the management of ecologically fragile dryland habitats, particularly the watershed terminus area, threatened by ongoing climate change, specifically in the context of the need to manage scarce water resources to promote sustainable socioeconomic development.