One of the shelters used to simulate extreme drought. It is located at the Central Plains Experiment Station in Colorado.
melinda smith
An experiment conducted at 100 sites around the world shows that during extreme droughts, grassland productivity declines much more than we thought. This finding suggests that plants may be struggling to cope with more frequent and severe droughts that are expected to result from climate change.
melinda smith Researchers at Colorado State University have designed a shelter that can be placed on top of land and topped with a piece of plastic to deflect some of the rain away from the vegetation below.
Working with other researchers around the world, Smith and her team were able to install such shelters in 100 grassland or shrubland locations across six continents.
For each site, Smith said, the team aimed to recreate conditions that would be considered extreme drought in the area, the type of conditions that occur once every 100 years. For example, in areas of Europe with high rainfall, more plastic strips are placed on roofs compared to drier areas to better simulate drought.
A year later, the researchers discovered that while some experiments were successful in reproducing drought conditions, others were unsuccessful because certain areas had higher than average rainfall.
In the 44 sites that experienced extreme drought, plant growth decreased by 38% in grasslands and 21% in shrublands. “That was huge,” Smith said, adding that the reduction in plant growth was much more severe than the researchers had observed in previous studies.
They also found that arid regions with low biodiversity are particularly vulnerable to drought. “Dry places are already at their limit,” Smith said. “Their systems don't have a lot of buffers to deal with it.”
Smith hopes these insights can improve global climate models that have previously underestimated the role of drought in the carbon cycle.
topic:
Source: www.newscientist.com
