Prompt Description

Soil biodiversity in apple orchards is crucial for productivity but is often investigated for only a limited number of organismal groups. We examined the soil biodiversity of bacteria, protists, fungi, and invertebrates in 26 apple orchards in Northern Italy using environmental DNA metabarcoding of the 16S and 18S ribosomal RNA, ITS, and COI marker genes. Chemical and biological parameters were assessed from the upper 20 cm of soil during the summer of 2023. We employed alpha- and beta-diversity analyses, distance decay relationships, immigration rates, community assembly processes, variance partitioning between space and environment, and putative bacterial and fungal functions to comprehensively understand the drivers of soil communities. Bacteria and protists exhibited higher immigration rates than the other two groups, supporting the size-plasticity hypothesis. The generally low immigration rate for all groups was linked to the low number of taxa occurring across all sites. Soil communities were primarily assembled by stochastic processes.