A study led by IRNAS-CSIC published in the prestigious journal Nature Ecology and Evolution (https://doi.org/10.1038/s41559-023-02071-3) suggests that changes in water availability can have drastic consequences on the biodiversity and functioning of our soils.

Soils host a huge part of the Earth's biodiversity and maintain multiple ecosystem functions essential for human well-being ranging from carbon sequestration, regulation of the water cycle to soil fertility. "95% of the food we consume depends directly or indirectly on our soils, so it is essential that we learn to predict changes in biodiversity and soil functioning in the context of climate change" says Manuel Delgado-Baquerizo, leader of the Biodiversity and Ecosystem Functioning Laboratory at IRNAS-CSIC and senior author of the article.

Environmental thresholds are known to govern global vegetation patterns, but whether they can be used to predict the distribution of soil organisms and functions in global biomes remains unknown.  ""

Using a global field study of 383 sites with contrasting climatic and vegetation conditions, we demonstrate that biodiversity and soil functions show generalized nonlinear patterns that are explained by water availability (precipitation/potential evapotranspiration). ""

Changes in water availability caused dramatic changes in soil biodiversity (bacteria, fungi, protists, and invertebrates) and soil functions, including plant-microbe interactions, plant productivity, soil biogeochemical cycling, and soil carbon sequestration. ""

Our findings highlight that crossing specific thresholds of water availability can have critical consequences for the provision of essential ecosystem services needed to sustain our planet. "Our planet is subject to major changes in water availability that influence biodiversity and soil health. Our study shows that in places with low levels of precipitation, as is the case in the transition between semi-arid and arid zones, small changes in water availability can be associated with drastic changes in soil health." concludes Delgado-Baquerizo who leads the CSIC BioFun Associate Unit at the Pablo de Olavide University.

Picture. Open forest ecosystem from Arizona, USA. Picture from Manuel Delgado Baquerizo.

Picture. Grasslands from Colorado, USA. Picture from Manuel Delgado Baquerizo.

Youzhi Feng, Nanjing Forestry University

Manuel Delgado-Baquerizo, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS)