Greater biodiversity shields forests from climate extremes, say scientists

Having a large variety of plant and tree species as well as fertile soils rich in organic life helps forests to better withstand the impacts of climate change, particularly droughts, new research has found. 

When a forest's canopy is made up of a many different species, it acts as a buffer that preserves the forest’s microclimate – and therefore its ecosystem, scientists have found. © AFP - MARIANA SUAREZ

Published on Monday in the journals Global Change Biology and PNAS, two studies carried out by French, German and Chinese scientists underpin the critical importance of fostering biodiversity. 

When a forest's canopy is made up of many different species, it acts as a buffer that preserves the forest’s microclimate – and therefore its ecosystem – because there are fewer temperature and humidity extremes. 

"This means that when there are very high temperatures, it will be a little cooler in forests with great biodiversity," CNRS researcher Stéphan Hättenschwiler, who participated in the studies, told RFI. 

Forest field work

By conducting field experiments in five types of forests across China, the researchers also found that high biodiversity helps tree leaves to decompose, even during periods of drought.  

Leaf litter breakdown, essential for the proper functioning of forests, is also helped along by the presence of organisms in the soil such as earthworms, centipedes and mites. 

"When you have a more species-rich leaf litter and a more complex network of decomposer organisms, this diversity can counteract the negative effects of drought," Hättenschwiler said. 

"So it’s a kind of insurance against extreme conditions."

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To achieve their results, the scientists created drought conditions in the forests – which ranged from temperate to tropical ecosystems – using so-called rainfall exclusion systems. 

They say their findings demonstrate the urgent need to move away from monocultures and to promote the diversity of trees in the world’s forests. 

The team is pushing for the findings of the studies to be integrated into ecosystem management practices for both forests and grasslands.