Reduced C3 plants on the southeastern margin of the Tibetan Plateau during the Late Pleistocene and implications for human dispersal into southern China

Abstract

Determining the vegetation that prevailed on the southeastern margin of the Tibetan Plateau during the Late Pleistocene is critical to debates on human dispersal into East Asia during the early Late Pleistocene. Here, we present a carbon stable isotope (δ¹³C) record for lake sediments from Tengchong Qinghai Lake in Yunnan, and we reconstruct the vegetation changes over the past 90000 years in terms of the relative abundances of C₃ and C₄ plants. Our δ¹³C record shows that the vegetation shifted from C₃-plant dominance to more mixed C₃ and C₄ plants during 78.6 to 58.6 ka B.P., indicating a shift to a more open forest environment. These changes coincided with the occupation history of Homo sapiens in southern China. We propose that a biome shift from dense forest to more open environments on the southeastern margin of the Tibetan Plateau may have provided dispersal corridors into southern China.