Fairy circles are mysterious natural formations that can be observed in dry areas. Fairy circles are circular patterns of bare soil surrounded by plants forming vegetation circles, which have so far only been described in Namibia and Australia. The researchers published their work in PNAS – phys.org Reports.
Over the years, many hypotheses have been put forward to explain the formation, but until now we have not known the global dimension of the phenomenon and the environmental factors that explain the phenomenon. Since fairy circles were only known from Namibia and Australia, the climatic, edaphic and environmental factors that determine fairy circle distribution have not yet been analyzed on a global scale.
The researchers classified satellite images with artificial intelligence-based models and found 263 locations where patterns similar to the imaginary circles have been described so far: Namibia and Western Australia, including the Sahel, the western part of the Sahara, the Horn of Africa and Madagascar. Or southwest Asia or central Australia.
Study proves that imaginary circles are more common than previously thought. The researchers found that a combination of soil and climate characteristics, such as nitrogen content and average rainfall of less than 200 mm per year, were associated with the presence of fairy circles.
The study took into account multiple variables that had not been taken into account until now, such as albedo or the condition of water tanks. This is a particularly important factor, as extensive groundwater use in arid regions around the world, including deserts, can disrupt these formations.
The researchers compared the stability of primary productivity of fairy circle plants and other ecosystems, and found that where fairy circles were present, there was greater stability.
This is the first experimental evidence of increased stability of fairy circle productivity, which is a key feature of ecosystems, and stable productivity is linked to a fixed reserve of ecosystem services, such as the amount of forage. These results can be used to investigate whether these spatial patterns are indicators of ecosystem degradation due to climate change, as is the case with other patterns of vegetation in dry areas. The study provides a global atlas of fairy circles and a database that may be useful in determining whether fairy circle vegetation patterns are more resilient to climate change and other disturbances.
The researchers published their study in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).