The future of stream monitoring: DNA Metabarcoding!

Macrozoobenthic invertebrates are used as indicator taxa worldwide to monitor stream health. Unfortunately, invertebrate larvae are often difficult to determine based on morphology, leading to misidentifications and wrong classification of the ecological status. This can, in the worst case, lead to suboptimal management decisions. These problems can be solved with DNA barcoding of the Cytochrome c oxidase subunit I (COI), which can reliably identify taxa on species level. With high throughput sequencing, it is now possible to identify thousands of specimens at once (DNA metabarcoding).

We performed several pilot studies using freshwater invertebrate mock communities to carefully test and evaluate new and innovative protocols. We also explored alternative ribosomal markers (16S) and developed new optimized COI metabarcoding primers for monitoring of freshwater invertebrates. Finally, the new approaches were tested using 20 samples taken from the reference water body Kleine Schmalenau (Arnsberger Wald, NRW) according to the European Water Framework Directive to directly compare the performance of classical morphological with DNA based identification of bulk samples. In my talk I will show the potential of the novel techniques for river monitoring but also highlight ongoing challenges that need to be addressed when developing a conceptual framework of future stream ecosystem assessments.