Increasing the number of stressors reduces soil ecosystem services worldwide

Increasing the number of environmental stressors could decrease ecosystem functioning in soils. Yet this relationship has not been globally assessed outside laboratory experiments. Here, using two independent global standardized field surveys, and a range of natural and human factors, we test the relationship between the number of environmental stressors exceeding different critical thresholds and the maintenance of multiple ecosystem services across biomes. Our analysis shows that having multiple stressors, from medium levels (>50%), negatively and significantly correlates with impacts on ecosystem services and that having multiple stressors crossing a high-level critical threshold (over 75% of maximum observed levels) reduces soil biodiversity and functioning globally. The number of environmental stressors exceeding the >75% threshold was consistently seen as an important predictor of multiple ecosystem services, therefore improving prediction of ecosystem functioning. Our findings highlight the need to reduce the dimensionality of the human footprint on ecosystems to conserve biodiversity and function. The authors investigate relationships between various soil stressors that exceed critical thresholds and the maintenance of ecosystem services. They show that multiple stressors crossing a high-level threshold reduces soil functioning and can be consistently used to predict ecosystem functioning.