Metabarcoding for biodiversity inventory blind spots: A test case using the beetle fauna of an insular cloud forest

Soils harbour a rich arthropod fauna, but many species are still not formally described (Linnaean shortfall), and the distribution of those already described is poorly understood (Wallacean shortfall). Metabarcoding holds much promise to fill this gap, however, nuclear copies of mitochondrial genes, and other artefacts lead to taxonomic inflation, which compromises the reliability of biodiversity inventories. Here we explore the potential of a bioinformatic approach to jointly “denoise” and filter non-authentic mitochondrial sequences from metabarcode reads to obtain reliable soil beetle inventories and address open questions in soil biodiversity research, such as the scale of dispersal constraints in different soil layers. We sampled cloud forest arthropod communities from 49 sites in the Anaga peninsula of Tenerife (Canary Islands). We performed whole organism community DNA (wocDNA) metabarcoding, and built a local reference database with COI barcode sequences of 310 species of Coleop...