ARISA OTUsThe file ARISAOTUs.xlsx contains information about the presence (1) and absence (0) of band classes (300 - 1500 bp) in each sample. In the first column, sample IDs are given. The samples are described in detail in columns IM - IQ. 16S ribosomal amplicon pyrosequencing OTUsThe file 454OTUs.xlsx contains the OTU table that was obtained after analyzing the 454 data using mothur. The table gives information on how many sequences of a specific OTU were found in each sample (after randomly selecting the number of sequences present in the smallest sample (n= 494), as described in the paper). In the first row, only sample IDs are given (e.g. AWI1.vGM3F). The samples are described in detail in rows 2136 - 2140. Taxonomic affiliations of OTUs are given in columns CQ - CV. The original 454 sequence data are deposited in the NCBI Sequence Read Archive (accession number SRP014019).SIMPER heat mapsThe files Figure 2_SIMPER_Dilutions.xlsx and Figure 3_SIMPER_pH.xlsx contain the values on which the color-coding of the heat maps in figures 2 and 3 is based. Values were calculated based on the SIMPER analyses given in supplementary tables S3, S4 and S5 and summarize the contributions of single OTUs (16S ribosomal amplicon pyrosequencing) on the family level.