Mysterious 'Fairy Circles' in Africa's Namib Desert Get a New Explaination, But Questions Still Remain

Mysterious “Fairy Circles” in Africa’s Namib Desert are getting a new explanation. Mysterious fairy circles are circular grass patches that are dead in the middle.

So far the mysterious "fairy circles" have defied explanation. Theories about the mysterious fairly circles have included ants, termites and a grass-killing gas that emerges from the soil. New research suggests that the mysterious fairy circles could also be the natural result of subsurface competition for resources among plants.

The new theory says that the Namib Desert grasslands start off homogenous, but because of sparse rainfall and the poor nutrients in the soil grasses have intense competition. Strong grasses sap all of the water and nutrients from the soil, causing their weaker neighbors to die and a barren gap to form in the landscape.

The vegetation gap expands as the competition ensues, and the grass-free zone becomes a reservoir for nutrients and water. With the additional resources, larger grass species are then able to take root at the periphery of the gap, and a stable fairy circle develops. [See Photos of Mysterious Fairy Circles of the Namib Desert]

Walter Tschinkel, a biologist from Florida State University LiveScience. "It's a really good theory because it accounts for all the characteristics of fairy circles. "No other proposed cause for fairy circles has ever done that." Tschinkel was not involved in the study. Last year he discovered that fairy circles last about 24 years. Larger circles in the desert can last up to 75 years. Tschinkel’s studies haven’t told him why fairly circles form or why they disappear.

Fairy circles have confounded scientists for decades. University of Hamburg biologist Norbert Juergens claimed he found evidence to prove the termite their earlier this year, but Tschinkel is critical of the findings, claiming that Juergens confused correlation with causation.

Michael Cramer, a biologist at the University of Cape Town in South Africa told LiveSciece "I think the major hurdle that explanations have to overcome is explaining the regular spacing of the circles, their approximate circularity and their size. There's no real reason why termites would produce such large circles that are so evenly spaced."

Cramer says termites have a different role in fairy circles, "What sets up the circles is the competition between plants. Termites are a secondary phenomenon, and their role is to serve as a maintenance for the circles by killing off the grasses that spring up in the center of the circles."

Scientists once thought fairy circles were a kind of "self-organizing vegetation pattern," that happens when plants interact.

Cramer and his colleague Nichole Barger from the University of Colorado at Boulder tested the theory. Cramer said "We found that the size of the circle, the density and degree to which they occupy the landscape are all associated with the amount of resources available.”

Yvette Naudé, a chemist at the University of Pretoria, South Africa, is happy to see a hypothesis for fairy circles that doesn’t involve insects as a cause. She told LiveScience in an email "It is unclear how peripheral grass resource-competition could induce such abrupt and synchronized plant mortality over an entire patch. The answer to the enigma [of fairy circles] remains elsewhere."

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