Strange ‘fairy circles‘ in the grasslands of Namibia have puzzled scientists for nearly five decades, but a new study has shed more light on the baffling phenomenon.
According to international media reports, millions of circular patches, each a few metres wide, are found in the coastal desert region of Namib, around 80 to 140km from the Atlantic shoreline.
It was thought termites could be responsible for the phenomenon. But a new study, published in the journal Perspectives in Plant Ecology, Evolution and Systematics, suggests the circles could be caused by the grasses themselves adapting to the very limited supply of water.
It assessed sporadic rain events in numerous desert regions and analysed grasses, their roots and shoots, as well as potential termite root damage to explain these patterns, and concluded that the “fairy circles” are caused by plant water stress.
As per international media reports, researchers, including some from the University of Göttingen in Germany, found that the grasses “self-organise” into the geometrical formation to share out water in order to survive.
They installed soil-moisture sensors in and around the fairy circles to record the soil’s water content at 30-minute intervals, starting in the dry season of 2020 and up to the end of the rainy season of 2022.
Scientists also studied how the new emerging grasses around the circles affected the soil water within and around the circles, and assessed the differences in water infiltration between the inside and outside of circles in 10 regions across the Namib.
The findings revealed that, about 10 days after rainfall, the grasses were already starting to die within the circles while most of the interior area of the circles did not have grass germination at all.
About 20 days after rainfall, the struggling grasses within the circles were completely dead while the surrounding grasses were green.
Scientists then examined the roots of the grasses from within the circles and compared them with the green grasses on the outside.
They found that the roots of the grasses within the circles were as long as, or even longer than, those outside, indicating that the grasses were putting effort into the growth of roots in search of water.
However, they found no evidence of termites feeding on roots and it was not until 50-60 days after rainfall that root damage became more visible on the dead grasses.
Mystery of Namibia’s strange fairy circles finally solved
