Drivers and scale dependency of plant-fungal-bacterial community co-assembly across the Arctic (2005-2021)

Despite considerable attention to biodiversity patterns in the face of global change, it remains unknown whether the same ecological drivers shape patterns of diversity in prokaryotes versus eukaryotes and in microscopic, small and large organisms. Plants (large, eukaryotic), fungi (small, eukaryotic) and bacteria (microscopic, prokaryotic) interact intensively belowground and can reciprocally affect community compositions of the other kingdoms. Their combined interactions and activities comprise the nexus of ecosystem function in terrestrial biomes. This study examined the fundamental ecological drivers of community assembly (dispersal, environmental filtering, competition, facilitation, niche partitioning, neutral processes) of plant-fungal-bacterial (PFB) communities across hierarchical spatial and ecological scales in the Arctic. We used Illumina sequencing to analyze the fungal and bacterial communities from over 3500 soil samples collected at 11 sites along two latitudinal transects in North America and Eurasia. Each transect includes all five bioclimatic subzones and spans 1700 kilometers (km) North to South. Furthermore, we obtained plant community and environmental data from all sampling sites to address a series of hypotheses about the drivers of alpha and beta diversity as well as community composition separately and jointly across plants, fungi and bacteria. Here we present the assembled plant, fungal, bacterial and environmental data sets. We sampled the plants, environments and soils in the field from 2005 to 2010, and analyses of soil fungi (all the molecular work and processing of sequences and bioinformatics) were conducted from 2013 to 2021, for a total range of 2005-2021.