Across parts of Namibia’s dry grasslands, bare circular patches interrupt an otherwise vegetated landscape. Many have a conspicuous grassy rim; from above, their repeated spacing can look almost designed. These are the Namib’s fairy circles, a natural landscape puzzle whose research history includes satellite comparisons, soil transfers, buried barriers, termite investigations and continuous moisture monitoring. The name is picturesque, but the scientific dispute concerns ecology: what creates the gaps, what maintains them, and why do neighbouring circles form such distinctive patterns?
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A landscape with a history
This case concerns the Namibian circles, rather than every circular patch called a fairy circle elsewhere. The NamibRand Conservation Foundation describes them as a characteristic feature of its dune valleys and grassy plains. Its landscape account places the broader phenomenon along the Namib’s eastern margin, extending beyond Namibia into neighbouring countries. That conservation context matters: the circles belong to living, managed ecosystems, not an empty experimental surface. The foundation supports environmental education and research on the reserve. Its own account of the circles provides useful local context, while the scientific papers below provide the evidence for particular mechanisms.
2012: circles that appear and disappear
Walter Tschinkel’s 2012 life-history study replaced the impression of permanent marks with a changing population. Comparing satellite imagery from 2004 and 2008, and checking circles on the ground, he documented both newly appearing gaps and old circles becoming vegetated. He arranged their features into stages of appearance, maturity and disappearance, with occasional enlargement. The terminology of birth and death describes the visible vegetation pattern, not a separate organism.
Turnover calculations suggested an average lifespan around 41 years, while an independent estimate based on revisits suggested about 60 years. Larger circles appeared longer lived than smaller ones. These are estimates from observation windows and population changes, not the result of watching every circle continuously for six decades. The important advance was a new demand on explanations: a proposed cause had to accommodate formation, persistence and revegetation. Explaining only the striking aerial appearance would leave much of the phenomenon unexplained.
2013: water competition as a pattern-maker
Michael Cramer and Nichole Barger examined soil properties, water availability, climate and circle distribution in their 2013 study of vegetation self-organisation. They proposed that competition between grasses could generate bare gaps, while those gaps retained resources useful to the surrounding plants. Their measurements associated changes in soil moisture across circles with soil organic carbon, and linked landscape occupation by circles to precipitation and soil nitrogen. A regional model also connected their occurrence with a restricted combination of environmental conditions.
In this explanation, a repeated landscape pattern can emerge from interactions between many plants without anything drawing each circle. The paper’s proposed feedback combines competitive exclusion with benefits to surviving peripheral grasses. The authors treated the circles as resource reservoirs within an arid ecosystem. Their correlations and model predictions supported that interpretation, but should not be described as a filmed reconstruction of a circle’s first formation. The distinction between a mechanism consistent with observations and one directly manipulated in the field remains central to the later debate.
2015: moving soil and burying barriers
Tschinkel’s 2015 experimental paper describes work established in 2009 and checked through 2015. To test a subterranean gas explanation, impermeable barriers were buried beneath circles. To investigate whether circle soil itself suppressed plants, soil was exchanged between natural circles and artificially cleared patches, with control transfers. Other treatments added micronutrients or placed artificial gaps at different distances from existing circles.
The barriers did not produce the predicted difference in seedling growth; soil transfers did not change plant performance relative to their reference conditions; micronutrient additions likewise failed to produce the anticipated effect. Artificially cleared patches became vegetated while nearby natural circles remained bare. The experiments therefore narrowed several explanations under the conditions tested. They also found no support for the particular short-range vegetation interactions tested at that scale. Tschinkel discussed landscape-scale self-organisation as more promising. An artificial gap’s failure to become a lasting circle is especially informative: merely removing the grass does not reproduce whatever keeps a natural circle open.
The termite interpretation
A different interpretation gives sand termites an engineering role. Norbert Juergens, Alexander Groengroeft and Felicitas Gunter set out that position in their 2023 Royal Society paper, a synthesis incorporating additional findings. They argue that Psammotermes colonies eliminate newly germinated plants, reducing water loss through vegetation and preserving moisture in sandy soil. Bare centres and surrounding perennial grass then become parts of a system supporting termite survival in extreme aridity.
The authors discuss nest structures, colony biology and moisture observations, and interpret the circles as an adaptation of social insects to scarce, unpredictable rain. They also distinguish the Namib circles from other much larger vegetation gaps that have sometimes received the same name. Their explanation is an argued scientific position, not an interchangeable description of every bare patch. The causal question is more demanding than whether termites can be found there: researchers must determine whether their activities initiate the observed vegetation loss and sustain the landscape pattern. That is where other investigators challenge the termite interpretation.
2024: following the rain
Stephan Getzin and colleagues approached the changing landscape with drone mapping and repeated observations. Their 2024 Landscape Ecology study analysed ten plots and repeatedly mapped three through the 2020–2023 rainfall seasons. The most regular patterns occurred on deep sands where water infiltrated rapidly and uniformly. After substantial rainfall following drought, between roughly one third and more than half of the mature circles in the monitored plots became vegetated. The study counted 1,092 closing circles against 15 newly formed ones during that comparison.
Many gaps subsequently opened again. The authors interpret this responsiveness to rainfall, together with soil properties and pattern statistics, as evidence for water-mediated vegetation self-organisation. Their result changes the visual question into a temporal one: why do patches close after favourable rain and reopen as conditions change? It supports a specific ecological explanation, while still requiring care over comparisons between regions, soil depths and years. A bare patch photographed during drought and a green patch after rain may represent different states of the same location.
2025: the soil community inside the gaps
Amy Treonis, Andrew Bell, Eugene Marais and Gillian Maggs-Kölling added another layer in their 2025 study of soil nematodes. Sampling along a roughly 900-kilometre Namibian range, they compared circle centres, grassy rims and the surrounding vegetation. Nematode abundance and diversity were generally greater beneath the plants than in bare centres, whose low organic matter supported a much poorer soil food web. Community composition also differed among sites.
The study illustrates why the conspicuous surface pattern cannot be separated from the organisms below it. However, finding distinct communities inside established circles does not establish which process originally created the gap. The authors discuss organisms potentially responding to, and contributing to, the contrasting conditions. Their results expand the ecological investigation without providing a simple announcement that nematodes made the circles. Cause, consequence and maintenance can overlap, and a useful explanation must separate those roles rather than assign every observed difference to an initiating event.
What would resolve the disagreement?
Cramer and Tschinkel’s 2025 research review favours vegetation self-organisation but identifies important gaps in direct evidence about underground water and nutrient movements. It also challenges aspects of the termite hypothesis, including the consistency of colony locations and the relationship between termite populations and long-lived circles. Their proposed route forward is experimental: manipulate relevant factors, measure the responses and maintain long-term observations. That appraisal is a published assessment by participants in the research, not a vote settling the issue.
The case demonstrates how a natural mystery can become more precisely defined without every argument disappearing. Circle longevity, rainfall response, soil properties, animal activity and spatial regularity each constrain the possible explanations. Evidence for one component need not establish the whole causal chain. The sources support a history of competing ecological investigations; they provide no need to invoke a supernatural agent behind the pattern.
Location and source trail
The directory pin uses the published Jagkop research reference in Namibia’s NamibRand Nature Reserve from the 2013 paper. It indicates a researched landscape, not an individual circle, public entrance or permission to enter an experimental plot. The lead photograph depicts a different Namibian location, within Namib-Naukluft National Park, and is captioned accordingly. All studies are linked beside the relevant discussion. Sources checked on 5 November 2026. For another example of separating reported observations from the interpretation built around them, see our Trans-en-Provence ground-trace case.