Global Courant
Fairy circles arouse wonder among viewers and fuel the battle among experts. For decades, scientists have hotly debated the origins of the strange, dot-like patterns of arid earth found in the Namib Desert, which stretches from Angola to northern South Africa. Some researchers also say they occur in the Australian outback.
Now there is something new to discuss: to what extent are fairy circles found all over the world?
Findings based on satellite images published Monday in the Proceedings of the National Academy of Sciences raise the possibility that fairy circles exist. considerably more widespreadtaking place in up to 263 locations in 15 countries on three continents.
“We discovered fairytale locations in many other places that we didn’t know existed before, because most work on this topic has been carried out in just two countries: Namibia and Australia,” says Fernando Maestre, an ecologist at the university. from Alicante in Spain and author of the study.
Other researchers who have worked on fairy circles say it remains to be seen whether the newly identified circular, barren spots are true fairy circles until the fieldwork is done.
“Different types of bare patches exist in all arid areas of the world, which are caused by different processes,” says Norbert Jürgens, emeritus ecologist at the University of Hamburg, who was not involved in the study.
This study made Dr. Maestre and his colleagues are not part of the sometimes difficult brotherhood of fairy circle researchers. They got sucked into the mystery when Emilio Guirado, a data scientist at the University of Alicante and one of the study’s authors, spotted something strange on Google Earth: patterns in Niger that looked like fairy circles. He wondered if they might also occur in other dry habitats.
To find out, the researchers trained a pattern recognition model with images of well-known fairy circles from Namibia and Australia. They applied the model to satellite images of 575,000 2.5-hectare plots of dryland habitat around the world.
Although arid areas cover 41 percent of Earth’s land area, the researchers’ model identified only a small portion that may contain fairy circles: about 300 square kilometers. The researchers consulted satellite images to manually confirm that fairytale patterns occurred in almost all the places the model identified, from Kazakhstan to Madagascar.
Based on their findings, they created a profile of the types of habitats where fairytale patterns are most likely to occur: hot, dry places with sandy soil that is low in nitrogen and receives 4 to 12 inches of rain annually. .
Statistical tests confirmed that “the patterns we found are exactly the same patterns as what people in Namibia and Australia have found,” said Dr. Maestre.
Dr. Maestre said he and his colleagues went into their study well aware that fairy circles were “a hotly debated topic.” Partly because of this, they chose to be conservative in describing their findings as “fairytale circular vegetation patterns.”
“We’re not trying to fight anyone,” said Dr. Maestre.
Nevertheless, the new findings have sparked strong reactions.
“Unfortunately, the study waters down the term ‘fairy circle’ and ignores the definition of fairy circles,” says Stephan Getzin, an ecologist at the University of Göttingen in Germany.
In 2021,Dr. Getzin and colleagues argued that real fairy circles existed occur in a grid-like pattern with an ‘extremely strong’ order.
None of the newly identified fairytale holes match this strict pattern, said Dr. Getzin.
Walter Tschinkel, a biologist at Florida State University who was also not involved in the study, agreed with Dr. Getzin agree. Although the authors of the new paper “certainly found plenty of circular or circular openings in areas with arid climates and sandy soils,” he said, the pattern formation does not “really meet the criterion for fairy circles.”
Dr. Maestre responded that Dr.’s definition Getzin “was not supported by the entire scientific community working with fairy tale circles” and “does not undermine our findings in any way.”
Michael Cramer, an ecophysiologist at the University of Cape Town who was not involved in the research, said the lack of a standard definition of a fairy circle was a problem for the entire field.
“Unfortunately, the only guardians of the term ‘fairy circle’ are self-appointed,” said Dr. Cramer. “Achieving agreement on the naming of fairy circles would likely require the establishment of a Fairy Circle Convention on Nomenclature, which seems unlikely.”
Whatever the newly discovered gaps turn out to be, they give scientists plenty of work to do, says Hezi Yizhaq, an environmental physicist at Ben Gurion University in Israel, who was not involved in the study.
“Now we have 263 new sites to investigate,” he said. “This is what is so interesting and exciting about science: solving natural puzzles.”
