(ORDO News) — For years, scientists have been puzzled by the existence of circular bare patches scattered across African grasslands known as “fairy circles.” These mysterious formations have caused many theories and debates among researchers.
However, a recent study by biologist Prof. Dr. Norbert Jürgens and soil scientist Dr. Alexander Gröngröft from the University of Hamburg has finally shed light on this mystery. Their results confirm that termites are the true cause of fairy circles, refuting the previously accepted explanation that their formation was explained by the self-regulation of grasses.
Groundbreaking discovery
The groundbreaking discovery made by Professor Jürgens and Dr Gröngröft challenges the prevailing belief that fairy circles are the result of self-organization of herbs. Their study confirms that subterranean sand termites of the genus Psammotermes are responsible for the formation of bare patches. These termites destroy plants in sandy soils, which allows them to retain water for a long time after infrequent rains. This explanation was proposed by Professor Jurgens in 2013 and has since been supported by entomologists in South Africa.
Opposing theories
While Professor Jürgens’ explanation has gained widespread acceptance among researchers, other scientists, such as those at the University of Göttingen, have explored alternative theories using modeling approaches. These researchers hypothesized that the bare patches were the result of self-organization of herbaceous plants that draw water unevenly through their roots. This uneven distribution of water, combined with intense diffusion in sandy soils, eventually led to the death of herbaceous plants in bare areas.
Modelers’ refutation
In their latest study, Professor Jürgens and Dr Gröngröft directly refute the arguments put forward by the Göttingen modellers. Their study, published in the journal PPEES, involved studying more than 1,700 fairy circles in Namibia, Angola and South Africa, where they confirmed the presence of sand termites. These results contradict the modelers’ claims and provide concrete evidence in favor of Professor Jurgens’s original explanation.
Soil moisture debate
One of the central points of contention between the two theories concerns soil moisture measurements. Modelers cited these measurements as evidence for the self-organization hypothesis, suggesting that the drying out of the topsoil is due to water being taken up by surrounding grasses. However, research by Professor Jurgens in 2013 showed that fairy circles retain water in the subsoil for a long time. Measurements at different depths showed that fairy circles retain water even when the top layer of soil dries out.
Hydrological properties
To further confirm their findings, Professor Jürgens and Dr Gröngröft carried out extensive laboratory analysis of the hydrological properties of desert sand. These analyzes refuted modelers’ assumptions about self-regulation. They found that during heavy rainfall, the hydraulic conductivity of coarse sand in fairy circles, where termites live, is exceptionally high. However, once the sand gives up water and dries to less than eight percent of the soil volume, the situation changes dramatically.
Expert opinions
Professor Jurgens emphasizes the significance of his colleague’s analysis and the hydrological measurements carried out in the laboratory. He argues that these results undermine the self-regulation assumption put forward by the authors of the model.
“The water conductivity of the coarse sand of fairy circles, in which termites live, is indeed very high when a lot of water falls during heavy rain,” explains Professor Jürgens. “However, the situation is completely different when the sand releases easily moving water into the depths and dries to less than eight percent of the soil volume.”
The discovery that termites are responsible for creating fairy circles in African grasslands marks a significant breakthrough in our understanding of this natural phenomenon. With the knowledge gained, scientists will be able to further explore the environmental impacts and potential benefits associated with these intriguing formations.
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News agencies contributed to this report, edited and published by ORDO News editors.
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