highly significantP<0.005
Isotope ratios of rain and soil water showed a highly significant correlation during the wet season (R 2 = 0.61, P<0.005; Figures 3C–F ), when heavy rainfall occurs on a daily basis ( Figure 1 ), whereas no significant correlation was observed during February (R 2 = 0.21, p>0.05; Figures 3C–F ), when the rainfall was nearly 40 times lower ( Figure 1 ).