Human settlements and plant utilization since the late prehistoric period in the Nujiang River valley, Southeast Tibetan Plateau

The combined application of archeological excavation, radiocarbon dating, and macrofossil analysis in recent years has produced valuable datasets for understanding when and how humans settled on the Tibetan Plateau during late prehistoric times. Dozens of suggested prehistoric sites were found in the Nujiang River valley, Yunnan Province, Southwest China, located on the southeast edge of the Tibetan Plateau. Previously, however, the ages and plant use associated with most of these sites has remained unclear. To address this lacuna, we investigated archeological sites in the area, taking samples from seven sites for radiocarbon dating and macrofossil and microfossil analysis. Our results indicate the ages of these sites range between 2250 and 1250 cal BP, considerably younger than previous estimations determined by the characteristics of artifacts, and the identified crop microfossils from these sites are mainly remains of rice. To study the history of human settlement and their subsistence strategy in the Nujiang River valley, we further review the published results of radiocarbon dating and archaeobotanic studies. Humans had intensively settled in the Nujiang River since the late Neolithic period, and utilized a variety of crops including rice, millet, wheat and barley in the Bronze Age. Our work suggests that since the availability of archeological investigation and macrofossil analysis is limited in the Nujiang River valley, more systematic archaeobotanic study and radiocarbon dating from excavated sites are needed for the studying of past human activities in the area.