Fig 4. Isotope data by province, 5000–2000 cal BC.

Boxplots of human bone collagen δ¹³C (a) and δ¹⁵N values (b) by province from sites that date to between 5000–2000 cal BC arranged from north (left) to south (right). Regions are differentiated by color: Loess Plateau (red) and Yangtze-Huai (gray). Provinces sharing a letter are not significantly different (Tukey’s HSD). Statistics are summarized in S3A and S3B Table.