Multiple stressors shape soil microbial functional diversity worldwide

We collected soils from 200 sites on a global scale to measure stressors. Sampling sitesincluded all dominant terrestrial ecosystems, i.e., temperate forests, seasonal tropical forests, temperate grasslands, subtropical woodlands, polar tundra and shrublands, providing a good representation of the most common environmental conditions found in terrestrial environments on all seven continents. We considered ten common environmental factors that can result in stress when passing high levels. These factors were aridity (inverse of aridity index), temperature (maximum temperature), seasonality (precipitation and temperature seasonality and diurnal temperature range), extreme events(extreme dry events, extreme wet events, heatwave days), fire, salinity, distance from neutral pH(acidification), levels of heavy metals (soil As, Cd, Cr, Cu, Ni, Pb and Zn), human influence (for example, human-influence index and fertilization)and UV radiation.To evaluate the reliability and validity of the findings derived from the global field survey, we employed an additional dataset comprising 1409 sites distributed globally. This dataset encompassed a diverse range of ecosystem types, including alpine soil, bare land, desert, forest, grassland, shrubland, tundra and volcanic soil.