Soil organisms are a crucial part of the terrestrial biosphere. Despite their importance for ecosystem functioning, no quantitative, spatially-explicit models of the active belowground community currently exist. In particular, nematodes are the most abundant animals on Earth, filling all trophic levels in the soil food web. Here, we use 6,579 georeferenced samples to generate a mechanistic understanding of the patterns of global soil nematode abundance and functional group composition. The resulting maps show that 4.4 ± 0.64  10 20 nematodes (total biomass ~0.3 Gt) inhabit surface soils across the world, with higher abundances in sub-arctic regions (38% of total), than in temperate (24%), or tropical regions (21%). Regional variations in these global trends also provide insights into local patterns of soil fertility and functioning. These high-resolution models provide the first steps towards representing soil ecological processes into global biogeochemical models, to predict elemental cycling under current and future climate scenarios.

a global database of soil nematode abundance and functional group composition Johan van den Hoogen et al. # as the most abundant animals on earth, nematodes are a dominant component of the soil community. they play critical roles in regulating biogeochemical cycles and vegetation dynamics within and across landscapes and are an indicator of soil biological activity. Here, we present a comprehensive global dataset of soil nematode abundance and functional group composition. This dataset includes 6,825 georeferenced soil samples from all continents and biomes. For geospatial mapping purposes these samples are aggregated into 1,933 unique 1-km pixels, each of which is linked to 73 global environmental covariate data layers. Altogether, this dataset can help to gain insight into the spatial distribution patterns of soil nematode abundance and community composition, and the environmental drivers shaping these patterns.

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