30 Oct 2022 13:29 GMT
These are circles devoid of vegetation and located at the same distance from each other in the middle of arid areas.
A group of researchers led by German biologist Stephan Getzin has found new evidence to support self-organization theory with which previous studies have tried to explain the nature of the mysterious ‘fairy rings’ located in the Namib desert – along the coast of Namibia, southwest Africa – and western Australia.
These circles devoid of vegetation and equidistant from each other were explained by Getzin and his team as the result of various processes, such as soil erosion due to heavy rains, extreme heat, and evaporation. At the same time, at the edges of most of the ‘rings’ there is a growth of lusher grasscompared to the grass average.
Scientists now specify that herbs form these circles, which measure between 2 and 10 meters wideto make the most of the scarce rains.
in his last studythe researchers returned to the African country hoping to find even more conclusive evidence, for which they investigated ‘fairy rings’ in 10 regions of the Namib desert depending on the rains, which in this area are scarce and irregular. The group examined the weeds, their roots and shoots, and any possible root damage caused by termites.
After completing the observations, which began in the dry season of 2020 and lasted until the end of the rainy season of 2022, the scientists suggested that the plants were investing heavily in root growth to fetch water. In addition, the researchers found no evidence that the termites fed on the roots.
“The most important thing is that we can show that termites are not responsiblebecause the grasses die immediately after the rains, without any sign of creatures feeding on the root”, he pointed Getzin in a statement. “Under the intense heat of the Namib, grasses permanently perspire and lose water, so create moisture voids in the soil around its roots and the water is attracted to them”, explains the scientist.
As the researchers write, this is an incredible example of “ecohydrological feedback”in which the barren circles become reservoirs that help support the grasses at the edges.
“Herbs act as ecosystem engineers and benefit directly from the water resource provided by the gaps in vegetation,” says the lead author of the study. “In fact, we know of self-organized vegetation structures related to other harsh arid areas of the world, and in all these cases, the plants do not have another chance to survive than growing in exactly those geometric formations,” he adds.