TABLE A1.

Inputs and outputs of each preprocessing step

Preprocessing steps	Number of samples	Number of ASVs	Min. number of reads per sample	Max. number of read per sample	Filtered reads	Total
Raw	57	595	2042	76,134	0	2,074,038
Filter ASVs (non‐bacterial and ambiguous)	57	577	2042	76,134	2081	2,071,957
Filter samples	54	577	13,981	76,134	8916	2,063,041
Filter Contaminants	54	558	13,981	76,134	278	2,062,763
Rarefaction	54	518	13,981	13,981	1,307,789	754,974