Summary of regional richness.

Summary of Ephemeroptera (E), Plecoptera (P), Trichoptera (T) and combined EPT richness (mostly genus level) between the three regions taken from 80 streams across mid-latitude China. Results of pairwise Tukey's posthoc tests on generalized linear models are shown as letters at the top of each plot. Different letters represent significant differences between regions. Boxes represent the interquartile range (IQR), and whiskers are the furthest point within 1.5 x IQR above or below the IQR. Values beyond this range are plotted as individual points. The central line represents the median.