Abstract
Mapping diversity patterns across environmental gradients may predict how ecosystems will respond to climate change in the future. The soil biota, including protists, fungi and micro-invertebrates, are essential components of terrestrial ecosystems but it is so far not clear how these communities will respond to climate change. By analyzing soil and litter samples collected from various climates throughout Norway, the study aimed to assess how important climate is for structuring soil microeukaryote communities compared to other factors, including vegetation and local soil properties. To encompass a wide span of taxa and increase the phylogenetic resolution, long-read amplicon sequencing (PacBio HiFi) was applied with eukaryote-specific primers to obtain continuous reads spanning a ~4500 bp region of the rDNA operon (including parts of SSU and LSU genes, and the full ITS region). Sequencing of environmental DNA from soil and litter collected at 90 sites recovered over 13 000 OTUs, most of which were Fungi, Cercozoa, Metazoa, Alveolata and Streptophyta. Beta diversity analyses show significant differences in soil and litter community structures, in addition to strong community groupings by dominant vegetation type at the sampling site. Further, community structure groups indirectly along a highland/lowland-gradient. Alpha diversity is found to be differentially responsive to environmental variables among substrates and without a clear distinction between climatic and local factors. A potential diversity threshold is observed in the sequencing data and the application of long-read sequencing as a metabarcoding mapping tool is discussed.