Community response to spatial and environmental factors.

OTU3%: Clustered sequences from MPTS at 97% sequence identity; OTUARISA: OTU derived from ARISA fingerprinting; SSOabs: OTU3% with only one sequence in the whole dataset (absolute singletons); SSOrel: OTU3% with only one sequence in at least one sample but more than one sequence in the whole dataset (relative singletons). aThe significance of Spearman’s correlation coefficients (r) between relative OTU abundance tables and environmental parameter was determined by Mantel tests. bRedundancy analysis (RDA) and partial RDA (pRDA; in brackets; to evaluate factor effect while taking the effects of other parameters into account) were used to determine the amount of variation (R2 adjusted) in the community data in a variation partitioning approach. For pRDA, the used parameters were water depth and CPE concentrations. Note that covariation effects cannot be tested for significance in the variation partitioning context (e.g. [71]). Significance levels are indicated as ***: p≤0.001, **: p≤0.01, *: p≤0.05, ∼: not significant, p>0.05.