Harmful synergy of global change agents?

New research demonstrates the importance of analyzing the effects of environmental stressors together.

Environmental stressors resulting from human action such as global warming, soil acidification or pollution create synergies that worsen ecosystem services, ranging from biodiversity to soil fertility. For this reason, it is important to analyze their effects as a whole and not by adding each one separately, as can be deduced from the results of a study carried out by specialists from the Institute of Natural Resources and Agrobiology of Seville (IRNAS), dependent on the Superior Council of Scientific Research (CSIC), and in which the Complutense University of Madrid (UCM) has also participated, in Spain all these entities

The analysis shows that having multiple stressors –measures of global change agents–, starting at medium levels (>50%), is negatively and significantly correlated with impacts on ecosystem services.

When multiple stressors cross a critical high-level threshold (more than 75% of the observed maximum), soil biodiversity and its functioning globally are reduced.

“The planet is under pressure from multiple factors of global change. Our study demonstrates for the first time that, on a global scale, as the number of global change factors increases, the capacity of terrestrial ecosystems to maintain multiple ecosystem services also decreases,” explains Manuel Delgado-Baquerizo, an IRNAS scientist who leads the study. job.

In the study, ecosystem services such as biodiversity and soil fertility have been measured. (Photo: Amazings/NCYT)

“Although laboratory experiments indicating this pattern have been previously published, this study is the first to evaluate the synergy of global change agents in 200 real ecosystems, demonstrating that what was seen in these trials is corroborated,” adds Miguel Berdugo Vega, researcher from the Department of Biodiversity, Ecology and Evolution of the UCM.

To carry out the work, indicators of ecosystem services such as decomposition of organic matter, soil biodiversity, control of soil pathogens, regulation and provision of water, and soil fertility were measured in situ.

In parallel, various environmental stressors that are related to global change were measured, such as the amount of heavy metals in the soil, soil pH, human influence on the surroundings of the ecosystem, and various variables related to climate. Using statistical models, it was possible to develop an index that quantified the effect of the global change variables separately and as a whole, as well as their synergies in the various ecosystem services.

“This study allows us to quantify how much we are underestimating the impact of global change agents on ecosystem services when we analyze them one by one. In addition, it opens up various paths for future research to better understand how these synergies between agents of global change operate”, says Berdugo. “It is important – concludes Delgado-Baquerizo – that future research and environmental policies consider the impacts of multiple environmental factors simultaneously in order to estimate and predict the future of our ecosystems.”

In addition to INRAS and the UCM, the Autonomous University of Madrid in Spain, Alicante in Spain, Berlin in Germany, Zurich in Switzerland and Tartu in Estonia, among others, participated in the study.

The study is titled “Increasing the number of stressors reduces soil ecosystem services worldwide”. And it has been published in the academic journal Nature Climate Change. (Source: UCM / CSIC)