Environmental filtering weakens the latitudinal diversity gradients in soil biodiversity

The latitudinal diversity gradient (LDG) stands as the most predominant ecological theory explaining the global distribution of aboveground organisms, positing greater diversity in the tropics as compared to the poles. However, the validity of the LDG theory remains a subject of debate for belowground organisms worldwide, despite soil being the Earth's largest biodiversity reservoir hosting ~59% of global biodiversity. Here, we combined two independents (in terms of distribution and methods), global-scale databases to investigate the validity of the LDG theory in explaining global-scale patterns in soil biodiversity. This included a global survey based on amplicon sequencing involving 615 composite soil samples collected from 151 sites covering the major biomes; and a global database including metagenomic data from 4,856 soils across diverse biomes worldwide. Here, we aimed to scrutinize the validity of the LDG pattern for individual taxonomic groups across contrasting multitrophic groups of soil organisms.