Comparing earthworm biodiversity estimated by DNA metabarcoding and morphology-based approaches

Conventional identification based on morphology is today's tool of choice for monitoring earthworm diversity. However, it requires skills to distinguish specific features, which can become the bottleneck in soil ecological studies. DNA-based metabarcoding is increasingly used to monitor diversity of soil organisms. Few studies have compared this method with conventional methods. The aim of the study was to compare metabarcoding based on the mitochondrial 16S rRNA region with conventional morphology-based identification, where metabarcoding captured more species (eight) than identified by conventional method (five). Additionally, we tested the effects of two commercial DNA extraction kits: PowerSoil based on 0.25 g of soil and PowerMax based on 10 g of soil (both from Qiagen), where the PowerMax covered higher richness than PowerSoil.