Worldwide study reveals that soil ecosystems are under stress.

Scientists have discovered, after statistically analyzing data from all over the world, that numerous natural and human stressors are lowering biodiversity levels and the functionality of soil in soil ecosystems. This interaction is determined by the number and specific combination of those stressors. An international group of researchers led by Freie Universität biology professor Matthias C. Rillig arrived at this conclusion.

The consequences of their review have now been published in Nature Environmental Change, titled “Expanding the Quantity of Stressors Decreases Soil Biological System Administrations Around the World.”

To get by, soils and earthly environments all over the planet should fight with a great many regular and human stressors. Drought, warming, and exposure to harmful chemicals like microplastics are some examples. Not only does the variety of stressors but also the number of them, especially those brought on by human activity, have a negative impact on the soil’s processes.

“Our previous laboratory-based investigations have demonstrated that an increase in the number of global change variables led to a decrease in soil processes such as decomposition, soil aggregation, and soil respiration, as well as a decrease in soil biodiversity,”

Professor Rillig, lead author of the study and head of the research team,

According to Professor Rillig, the lead author of the study and head of the research team, which also included Spanish ecologist Dr. Manuel Delgado-Baquerizo, “our earlier laboratory-based studies have shown that an increased number of global change factors led to a reduction in soil processes such as decomposition, soil aggregation, and soil respiration, as well as a reduction in the biodiversity of the soil.”

The research team looked at two global standard field surveys on soils and a variety of human and natural factors that are known to have an impact on soil ecosystems.

“Our review assessed soil biological systems by sorting fifteen environmental factors into six principal kinds of biological system administration: soil biodiversity, pathogen control, organic matter decomposition, plant productivity, water regulation, and nutrient cycling. For the purposes of the review, we characterized seven significant ecological factors as stressors. When they reach high levels, these were chosen because of their potential to stress the environment: salinity, salinity, aridity, temperature, seasonality, distance from neutral pH, heavy metal concentrations, and human influence. Rillig explains, “We also took into account the level of pesticides and microplastics in the soil because we had data on these for a subset of locations in one of the global field surveys.”

The data from the global field surveys had to first be transformed into a variable that reflected the number of factors in order for the study to investigate the number of stressors as parameters. To accomplish this, the researchers counted the number of environmental stressors that exceeded a predetermined threshold value.

When the number of stressors exceeded 75% of the maximum stressor levels, a threshold had been reached. The investigation revealed that the soils’ capacity to support ecosystem services decreased as the number of factors above a certain threshold increased.

According to Rillig, “This increasing number of threshold-exceeding stressors could explain soil reactions that, up until this point, could not be attributed to the type of stressors alone.” “Humans must reduce their impact on ecosystems by decreasing the number of factors that negatively affect soil processes and soil biodiversity,” the study’s findings also demonstrated.

Soil processes and the biodiversity of soil ecosystems are influenced collectively by human influences. In the event that the degree of this issue, i.e., the quantity of stressors that surpass a basic edge, isn’t decreased, we risk losing significant environment administrations,” says Rillig.

Rillig also points out that the study relied primarily on observation. This indicates that while the researchers were able to identify patterns, they were unable to directly establish causality. To explain the relationship between the number of stressors and the ecosystem’s response, additional research will be required. The impacts of numerous simultaneous variables on different kinds of environments (for instance, sea-going frameworks) could likewise provide a possible future road of study.

More information: Matthias C. Rillig et al, Increasing the number of stressors reduces soil ecosystem services worldwide, Nature Climate Change (2023). DOI: 10.1038/s41558-023-01627-2

Soils worldwide suffer from the combined effects of multiple global change factors, Nature Climate Change (2023). DOI: 10.1038/s41558-023-01628-1 ,

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