highly significantp < 0.01
However, for carbon stable isotopes, the difference between the EH-GLG and XXL-LS populations reached a highly significant level ( p < 0.01); at the same time, the δ 13 C values of the hairs from the XXL-LS was different from the QL population ( p < 0.05), while the disparity of GLG and QL populations was not evident ( p > 0.05) in carbon isotopes ( Figure 3 a).