DNA metabarcoding illuminates the black box of soil animal biodiversity

Abstract

Identifying the determinants of the distribution of soil organism communities at different spatial scales is essential to our understanding of the functioning of terrestrial ecosystems. Indeed, spatial patterns of soil biota, and the factors that determine them, influence spatial patterns of many ecological processes such as the decomposition of organic detritus, the release of nutrients and, ultimately, the spatial structure of plant communities (Ettema & Wardle, 2002). However, our ability to describe and understand the spatial distribution of soil communities is severely hampered by taxonomic and methodological limitations, significantly reducing our ability to infer ecological and evolutionary mechanisms from observed patterns. In a From the Cover article in this issue of Molecular Ecology , Arribas et al. (2020) used a high‐throughput sequencing approach, i.e., haplotype‐level‐COI metabarcoding, to bypass these road blocks and analyse the spatial arrangements of soil arthropods communities at different phylogenetic levels, from haplotypes to nested operational units. They found that local assemblage composition was primarily explained by habitat, and that community similarity decreased with distance in a similar way in all habitats and geographical regions, and at all hierarchical levels. This highlights that both habitat filtering and dispersal limitation are major drivers of local‐scale assembly process in soil arthropod communities. Beyond these significant results, their study also highlights how DNA‐based approaches, by producing combined description of genetic and taxonomic diversity, opens up new perspectives to soil spatial ecology and macroecology.