Table 1.

The correlations (r) and significance (p) were determined by Mantel tests between geochemical variables and bacterial community composition in the sediments from all sampling sites, control sites and six-dam area sites (Ec, electrical conductivity; TOC, total organic carbon; TC, total carbon; TP, total phosphorus; TN, total nitrogen; NO₃^-, nitrate; NH₄⁺, ammonium; ^∗∗ represents significant correlations at p < 0.01).

Variable	All control sites (non-dam control and dam-control sites)		Six-dam cascade area sites (dam-control and dam-affected sites)
	r	p	r	p
Moisture	0.21**	0.001	0.25**	0.001
pH	0.47**	0.001	0.27**	0.001
Ec	0.12	0.058	0.16	0.018
TC	0.09	0.034	0.13	0.022
TN	0.62**	0.001	0.32**	0.001
C:N ratio	0.24**	0.001	0.07	0.123
TP	0.12	0.075	0.17**	0.007
TOC	0.54**	0.001	0.18**	0.004
NO3-	0.61**	0.001	0.26**	0.001
NH4+	0.10	0.111	0.15	0.023
Elevation	0.55**	0.001	0.29**	0.001