Fig. 1 Location of the study area and 52 sampling sites in the river ecosystems in the Qinling Mountains. Green dots represent the sampling sites in numerical order as summarized in the Supporting Information (Table S1). W, Weihe River; HJ, Hanjiang River; LF, Luofu River; B, Bahe River; SD, Shidi River; ST, Shitou River; H, Heihe River; JQ, Jinqian River; JS, Jinshui River; X, Xuhe River; XS, Xushui River; and Y, Yuehe River