The Fairy Circles are enormous circular patches of bare land with diameters ranging from 2 to 15 meters. They are typically found in the arid grasslands of the Namib Desert (located in southwestern Africa), and are particularly common in Namibia.
Situated around 80 to 140 kilometers from the coast of the Namib Desert, there are millions of fairy circles—circular bare patches on the grasslands, each several meters wide. Scientists have puzzled over their origins for nearly half a century.
Recently, however, these circles have also appeared in the Pilbara region of Western Australia, a phenomenon that has long caused headaches for researchers.
Fairy circles appearing on the arid grasslands of the Namib Desert.
A report from a group of authors stated: “The patches of bare vegetation in the arid grasslands, similar to the fairy circles in Namibia, have appeared in the remote areas of Western Australia, 10,000 km away from Namibia.”
The phenomenon of thousands of hexagonal patches of bare land was first discovered in Namibia in 2009. African tribes previously believed that these mysterious circles were the footprints of gods. Some even thought that a dragon lived beneath this land, breathing bubbles to the surface, thereby creating the fairy circles.
In 2003, biologist Norbert Juergens from the University of Hamburg (Germany) suggested that the unusual bare patches in circular shapes on the sandy desert grasslands of Namibia were caused by the species Psammotermes allocerus.
Image of Psammotermes allocerus
Recently, scientist Michael Cramer from the University of Cape Town in South Africa announced a new discovery about the “culprit” behind the countless mysterious circles in the sandy desert grasslands of Namibia. It turns out that the underground competition among desert plants is the reason for the creation of these circles.
Michael Cramer explained that the nutrient-poor and low-rainfall soil in the desert has led to competition among various plant species. The stronger plants absorb all the nutrients, causing many seedlings and young plants in the area to wither, fade, and eventually become unable to grow. The “fairy circles” themselves serve as a vast resource, providing water and nutrients to the larger grasslands nearby. Biologist Walter Tschinkel from Florida State University (USA), who did not participate in the research, remarked: “This is indeed a novel finding that aligns well with the characteristics of these circles.“
About 10 days after rain, the grass in the circles begins to die.
A team of experts at the University of Göttingen installed several soil moisture sensors in and around the fairy circles to measure water content from the dry season in 2020 to the end of the rainy season in 2022. The data showed that about 10 days after rain, the grass within the circles began to die, and most areas inside the circles were completely devoid of sprouting grass. Twenty days after the rain, the grass in the circles was entirely dead and turned yellow, while the surrounding patches remained lush and green.
When examining the roots of the grass in the circles and comparing them with the green grass outside, the research team found that the roots of the grass in the circles were as long as or even longer than the roots outside. This indicates that the grass is making an effort to develop roots in search of water.
The research team found no evidence of termites eating the plant roots. When analyzing data on soil moisture fluctuations, they noted that the decrease in water in the soil inside and outside the circles occurred very slowly after the first rain, when the grass had not yet sprouted. However, when the surrounding grass had grown well, the decrease in soil water after the rain happened very quickly across all areas, even when there was hardly any grass in the circles to absorb the water.
A car passing through the NamibRand Nature Reserve, one of the locations with fairy circles in Namibia. (Photo: Stephan Getzin).
Getzin explained that under the intense heat in Namibia, the grass continuously transpires and loses water. Therefore, they create “moisture chambers” around their roots, and water is drawn towards them. “Our results align with findings from other researchers showing that water in the soil disperses rapidly horizontally in this type of sand, even over distances greater than 7 meters,” said Dr. Stephan Getzin from the Ecosystem Modeling Department at the University of Göttingen.
“By creating a landscape with evenly spaced fairy circles, grass acts as an ecological engineer and directly benefits from the water provided by the bare patches of vegetation,” he added.
This new research helps scientists better understand similar ecosystems, especially in relation to climate change, as the self-organizing ability of plants helps combat the negative impacts that arise when environments become increasingly arid.
