*2.4. Library Preparation and Sequencing*

A simplified two-step PCR using primers for DNA barcodes fused with Illumina adaptor sequences was performed for DNA library preparation as described elsewhere [35,37]. Products of the first PCR for each barcode were mixed equimolar (or by volume if product concentration was below detection level) for each sample, indexed in the second PCR, and sequenced on the MiSeq platform with the MiSeq Reagent Kit v3 for 600 cycles (2 × 300 nt paired-end) (Illumina, San Diego, CA, USA).
