Cover Picture and Issue Information

Macrozoobenthic organisms are widely used to assess stream ecosystem health. Traditionally, this was done by morphological determination. However, the mostly larval specimens can often not be reliably identified to species level. DNA metabarcoding provides reliable solutions here. Rather than studying individual specimens, the complete invertebrate sample is thoroughly homogenised using liquid nitrogen for DNA extraction of the whole community, as shown on the picture. Then a specific “barcoding” gene fragment is amplified using PCR, sequenced on a high‐throughput sequencer and compared against available reference databases for taxonomic assignment. As benthic communities are usually very diverse, the PCR primers have to be designed to work on all the targeted groups like may‐ stone‐ and caddisflies, aquatic beetles and molluscs. Here the R package PrimerMiner assists in primer development by automated batch downloading and processing of sequence data from public databases, as well as visualising sequence diversity for each group to find potential universal primer binding sites. Photo credit: © Vasco Elbrecht