Mysterious “fairy circles” in Namibia and Australia are not so rare after all, the study says

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So-called fairy circles, or bare patches that form patterns that can stretch for miles, appear on the edge of the Namib Desert in Namibia.

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Round discs of barren dirt known as “fairy circles” look like rows of polka dots that can spread for miles above the ground. The mysterious origins of this phenomenon have intrigued scientists for decades, and it may be much more widespread than previously thought.

Fairy circles have previously only been spotted in the arid lands of South Africa’s Namib Desert and the outback of Western Australia. But a new study used artificial intelligence to identify plant patterns that resemble fairy circles in hundreds of new locations across 15 countries on three continents. This could help scientists understand chimeric circuits and their composition on a global scale.

For the new survey published Monday in the magazine Proceedings of the National Academy of SciencesThe researchers analyzed datasets containing high-resolution satellite images of Dry landsOr arid ecosystems with scant rainfall from around the world. The search for imaginary circuit-like patterns used a neural network, a type of artificial intelligence that processes information in a manner similar to that of the brain.

“Using AI-based models on satellite images is the first time this has been done on a large scale to detect imaginary circle-like patterns,” said lead study author Dr. Emilio Gerado, a data scientist at the Interdisciplinary Institute for the Environment. Studies at the University of Alicante in Spain, in e-mail.

First, the study authors trained the neural network to recognize imaginary circles by inputting more than 15,000 satellite images taken over Namibia and Australia. Half of the pictures showed fairy circles, and the other half did not. The scientists then fed their AI a dataset with satellite observations of nearly 575,000 plots of land around the world, each about 2.5 acres (1 hectare) in size. The neural network scanned the plants in those images and identified recurring circular patterns that resembled well-known imaginary circle patterns, and evaluated the circles’ sizes and shapes as well as their locations, pattern densities, and distribution.

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The results of this analysis then required human review, Girado said. “We had to manually eliminate some artificial and natural structures that were not fairy circles based on the interpretation of the images and the context of the area,” he explained.

The results showed 263 dryland sites where circular patterns similar to the imaginary circles in Namibia and Australia existed. These arid regions were distributed throughout Africa (the Sahel, Western Sahara and the Horn of Africa) and were also clustered in Madagascar and western Central Asia, as well as central and southwestern Australia.

Fairy circles aren’t the only natural phenomenon that can produce round, repeating spots in a landscape. One factor that distinguishes fairy circles from other types of vegetation gaps is the presence of a strongly organized pattern between the circles, said Dr. Stefan Getzen, a researcher in the Department of Ecosystem Modeling at the University of Göttingen in Germany.

Getzen and colleagues published a paper in November 2021 Definition of imaginary circles And what made it unique, focusing on the details of the overall style structure, he told CNN in an email. According to Getzen, who was not involved in the latest study, the newly discovered patterns are insufficient.

“Imaginary circuits are defined by the fact that, in principle, Ability to form a “spatial periodic” pattern.which is “significantly tidier” than the other patterns — and none of the patterns in the survey exceeded that high threshold, Getzen said.

But in reality, there is no universally accepted definition of imaginary circles, Girado said. He and his colleagues identified potential chimeric circuits — by measuring the size and shape of individual circuits, as well as the patterns they form collectively — by referring to guidelines established across several published studies. The scales of those spatial patterns, in the old and new fantasy circuits, are “about the same,” he said.

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Of the new locations identified, some have succeeded in gaining approval from Dr Fiona Walsh, who as part of an international team investigated fairy circles in the Australian outback. “The distribution of patterns in Australia appears to be consistent with some of what we have previously reported,” Walsh said. An ethnomethodologist at the University of Western Australia. Walsh did not participate in the new poll.

The study authors also compiled environmental data where the circles were observed, collecting evidence that might hint at what causes their formation. The researchers determined that the fairy circle-like patterns were more likely to occur in very dry, sandy soils that were high in alkalinity and low in nitrogen. Scientists also found that the fairy circle-like patterns helped stabilize ecosystems, increasing the area’s resistance to disturbances such as floods or severe drought.

But the question “What constitutes imaginary circles?” The study’s authors report that the matter is complex, and that the factors that create fairy circles may vary from location to location. Getzen previously wrote that certain climatic conditions, coupled with self-regulation in plants, generated fairy circles in Namibia, and while insects like termites take advantage of dry spots, their activities do not directly produce the patterns, he said in the email. .

However, Walsh said fairy circles in Australia were closely linked to termite activity. Their team researchConducted in close collaboration with Aboriginal people, she said termites in Western Australia and in the Northern Territory are integral to the operation of fairy circles, called “linyji” in the Manyjilyjarra language, and “mingkirri” in the Warlpiri language. CNN in an email.

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“Indigenous people have been explaining these patterns since at least the 1980s, and said they have known them for generations, perhaps thousands of years,” Walsh said.

“In Australia, termites don’t just play a role,” she added. “It is the basic mechanism and explanations should focus on termite, grass, soil and water dynamics.”

Many questions about the fairy circles still need to be answered, and the authors of the new study are optimistic that their global atlas will open a new chapter in the study of these strange barren spots.

“We hope that the information we publish in the paper will provide scientists around the world with new areas of study that will solve new mysteries in the formation of chimeric circuit patterns,” Girado said.

Mindy Weisberger is a science writer and media producer whose work has appeared in Live Science, Scientific American, and How It Works.

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