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Fairy circles are circular patches of barren land, varying between 2 and 12 metres (7 and 39 ft) in diameter, often encircled by a stimulated growth of grass.

They occur in the arid grasslands of the Namib desert in western parts of Southern Africa and in a part of the Pilbara in Western Australia. Theories include hypotheses that the activities of various types of termites affect growth or that competition between grasses naturally yields certain vegetation patterns. In the languages of the Aboriginal Australian peoples who inhabit the Pilbara, they are known as linyji (Manyjilyjarra language) or mingkirri (Warlpiri language).

Until 2014, the phenomenon was only known to occur in the arid grasslands of the Namib desert in western parts of Southern Africa, being particularly common in Namibia. Australian environmental engineer Bronwyn Bell, alongside Stephan Getzin from the Helmholtz Centre for Environmental Research, released a paper in 2016, providing new insight into possible cause of the fairy circle formations.

Fairy circles typically occur in essentially monospecific grassy vegetation, where conditions are particularly arid. In the languages of the Martu and Warlpiri peoples of Western Australia, fairy circles are known as "linyji" in the Manyjilyjarra language and "mingkirri" in the Warlpiri language. But from a scientific perspective, termite linyji are common vegetation gaps and not true fairy circles.

Ecologists have hypothesized about why fairy circles appear in arid landscapes, and these can be grouped into two main theories: a termite origin hypothesis, and a vegetation self-organization hypothesis. Juergens found evidence that the sand termite, Psammotermes allocerus, generates a local ecosystem that profits from and promotes the creation of the fairy circle. Sand termites create the fairy circle by consuming vegetation and burrowing in the soil to create the ring. Grass growth around the circle is promoted by the accumulated soil water, and in turn the termites feed on the grasses, slowly increasing the diameter of the circle. However, Namibia's leading termite expert, Eugene Marais, searched specifically for sand termites and came to the same conclusion: "We have not found such a ubiquitous presence of sand termites at fairy circles as was suggested by Juergens when carrying out ad hoc searches throughout the fairy circle range." Unresolved questions remain about the soil from the centre of the circle inhibiting plant growth and the interactions of other species in the fairy circle as they relate to the local ecosystem. They examined the conditions under which fairy circles arise and found that fairy circles are negatively correlated with precipitation and soil nutrition. According to Walter Tschinkel, this theory accounts for all the characteristics of fairy circles, including the presence of tall grass species. However, a large meta analysis of worldwide insect and fairy circle patterns in drylands confirmed earlier conclusions, showing that nest patterns of termites differ significantly from fairy circles. In 2022, a study was published that tested the termite theory and the theory of plant self-organization for Namibia by excavating hundreds of grasses within and around the fairy circles. Several fairy circle researchers stated that "The new study showed "conclusively" that termites were not a factor". In 2024, it was shown that the topsoil within the fairy circles is significantly drier than outside in the matrix and that new emerging seedlings quickly die in fairy circles due to desiccation. Detailed research on the specific Australian fairy circles, conducted between 2014 and 2019, has shown that the bare-soil gaps are caused by abiotic weathering of the soil surface, resulting in clay crusts and inhibition of grass growth within the circles. Thus, Australian fairy circles and termite linyji are different and not caused by the same mechanism.

In some cases, fairy circles have disappeared within a span of 10 years or less, while other fairy circles may have lasted for centuries.

Quick Facts

• They occur in the arid grasslands of the Namib desert in western parts of Southern Africa and in a part of the Pilbara in Western Australia.
• Grass growth around the circle is promoted by the accumulated soil water, and in turn the termites feed on the grasses, slowly increasing the diameter of the circle.
• Unresolved questions remain about the soil from the centre of the circle inhibiting plant growth and the interactions of other species in the fairy circle as they relate to the local ecosystem.
• However, a large meta analysis of worldwide insect and fairy circle patterns in drylands confirmed earlier conclusions, showing that nest patterns of termites differ significantly from fairy circles.
• Fairy circles typically occur in essentially monospecific grassy vegetation, where conditions are particularly arid.

Source material: Wikipedia - "Fairy circle (arid grass formation)". Adapted and summarized for DiscoverScroll. Original contributors are credited through the linked Wikipedia article. Read original on Wikipedia. CC BY-SA 4.0. Changes were made from the original.