Regional patterns of pastoralist migrations under the push of reduced precipitation in imperial China

Abstract

Aim: As a response of pastoralists to climate change, nomadic migration deeply shaped Chinese history during the imperial era. Existing research on climate‐driven nomadic migration is conducted mainly on a national–continental scale. To advance the current work, we aim to resolve migratory movements at a provincial–regional scale using a large and long‐term historical dataset as a first attempt. The spatio‐temporal features of nomadic migration under climatic effects, specifically precipitation, are analysed in the theoretical context of behavioural ecology.

Location: China.

Time: Imperial era (220 BC–1910 AD).

Study subject: Nomadic pastoralist minorities in imperial China.

Methods: We frame the analysis using an ideal free distribution model. A total of 1,842 historical location records of pastoralist immigration are empirically examined. Precipitation anomalies and nomadic migration are statistically assessed with nonparametric and Poisson regression methods, and temporal interdependencies among provincial–regional migratory movements are explored with a vector autoregressive model.

Results: We divide imperial China into six regions according to statistical results and geographic factors. Overall, decreased precipitation and drought provoked pastoralist migrations in a north‐to‐south direction. Northern nomads, with an apparent preference for central China as a major destination, triggered the most conflicts with resident agriculturalists. Nomads originating from the Tibetan minority regions moved north‐eastward into Qinghai Province as their main destination.

Main conclusions: Long‐term regional patterns of pastoralist migration are closely associated with drought‐induced ecological change in imperial China. Climate‐driven dynamics assessed with long‐term historical data facilitate the understanding of climate–ecology–society interactions in behavioural ecology and macroecology. Moreover, findings from imperial China may imply that cultural acceptance and communications could avoid conflicts between immigrants and original residents when facing mass migration, an issue of growing contemporary urgency in many parts of the world.