21 December 2023

Biodiversity stabilizes soil temperature all year long

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In the parts of the soil characterized by greater plant diversity, there is a buffer effect that prevents excessive warming or cooling during the hottest and coldest times of the year, a German study says

by Matteo Cavallito

 

High plant diversity acts as a buffer against fluctuations in soil temperature, a phenomenon of crucial importance to ecosystem processes, researchers from the University of Leipzig, Friedrich Schiller University in Jena and the German Center for Integrated Biodiversity Research Halle-Jena-Leipzig (iDiv) have found. The study, published in the journal Nature Geoscience, thus highlights the existence of a possible natural solution to mitigate the effects of climate change, such as extreme weather events.

The soil study

“Soil temperature plays a central role in controlling important ecosystem processes related to water, carbon and nutrient dynamics, microbial activity and agricultural productivity,,” Yuanyuan Huang, a researcher at the Leipzig iDiv and lead author of the study, explained in a statement. To test the impact of biodiversity on soil temperature itself, the scholars analyzed data collected from 2004 to 2021 at an experimental site consisting of 80 plots with a variety of plants ranging from one to 60 species.

Temperature values were automatically recorded at a depth of five and fifteen centimeters at one-minute intervals over an 18-year period, during which time there was considerable climatic variability. For the entire period under study, the statement says, “plant diversity showed a remarkable ability to protect the soil from overheating in scorching heat and to help retain heat in colder periods.”

The mitigation effect lasts throughout the year

The data that emerged are particularly significant. In summer, for example, the temperature recorded in the areas with the greatest plant diversity was about 5°C lower when compared with plots without vegetation. At the same time, “on days with particularly low air temperatures, the soil temperature in the 60-species plant community was 1.48 degrees Celsius warmer than in the plots with no plants.”

The stabilizing effect of plant diversity resulted in reduced heat conduction in the last 60 centimeters of soil.

“Our findings reveal that plant diversity acts as a natural buffer, preventing soil heating in hot weather and cooling in cold weather” the study states. “This diversity effect persists year-round, intensifying with the aging of experimental communities and being even stronger under extreme climate conditions, such as hot days or dry years.”

Positive implications for climate

The results of the study have far-reaching implications. “Using structural equation modelling, we found that plant diversity stabilizes soil temperature by increasing soil organic carbon concentrations and, to a lesser extent, plant leaf area index,” the study states.

The researchers also claim that in some key ecosystems such as the great grasslands, for example, the stabilization of soil temperature provided by plant diversity could be critical “to mitigate the negative effects of extreme climatic events such as soil carbon decomposition thus slowing global warming.”