Two decades of compositional restructuring of soil biodiversity in Germany despite stable α- and β-diversity indices

Summary

Abstract Soil ecosystems host some of the most taxonomically and functionally diverse biological communities on Earth, yet long-term trends in their biodiversity remain poorly understood. Here, we analysed soil biodiversity dynamics over 20 years with samples archived in the German Environmental Specimen Bank. We assessed temporal and spatial patterns in α-diversity and β-diversity with shotgun metagenomics across bacteria, fungi, and metazoa. We found no statistically significant temporal trends in α-diversity for any group. Total β-diversity also appeared temporally stable. However, decomposing β-diversity into its balanced variation and abundance gradients revealed taxon-specific compositional restructuring. Bacterial and fungal communities showed signs of compositional homogenisation,