Plants suffer greater damage from periods of drought than originally thought

We were aware that drought damages plants - but not to what extent. Since an international study involving the University of Innsbruck, it is now known that extreme droughts reduce plant growth by 60 percent.

"Overall, our results show with unprecedented precision that the global impact of the predicted increase in drought has been significantly underestimated," it says in the PNAS journal in which the study was published.

Standardized, artificially induced droughts over the course of a year were investigated at one hundred locations on six continents. These included locations in Germany and Switzerland.

Michael Bahn from the Institute of Ecology at the University of Innsbruck was part of the research team.

Meadows

For example, the team from the Bern University of Applied Sciences' School of Agricultural, Forest and Food Sciences(BFH-AFL) in Thun, Switzerland, covered six meadow areas with Plexiglas slats so that around 33 percent less rain could reach the ground than usual.

This was a simulation of the exact amount of annual precipitation in the driest year of the last hundred years.

Six further, equally large areas without a Plexiglas roof served as "control areas".

The species composition and the function of the ecosystem before, during and after the simulated drought were precisely recorded. The result was that the areas with extreme droughts were able to produce around 60 percent less plant growth.

New multiplier of the climate crisis

As grasslands and shrub steppes cover more than 40 percent of the Earth's ice-free land area and as such have an important carbon sequestration function (they store more than 30 percent of the global carbon stock), their disappearance in the wake of more intense droughts has a major impact on the global climate, according to ecologist Andreas Stampfli, who was involved in the study.