Generalized additive mixed models showing influences of conductivity, pH and TN on the relative abundance of each RDA taxa group at each site. The area within the dotted lines indicate the approximate 95% confidence intervals for the fitted functions (LOESS). The tick marks inside the panels on the x-axis show the distribution of the observed values for the two covariates. The numbers in brackets on the y-axis are the effective degrees for each smoother. Responses of each RDA taxa group to important predictors were provided in supplementary Figure 6.