Are geoengineering insects behind Africa's bizarre fairy circles?

A German scientist has come up with an explanation for the strange rings of grass that pockmark vast expanses of Africa's Namib Desert: A sand termite known as Psammotermes allocerus. These circles are actually tiny oases built by the insects — and they can allow life to persist in the harsh conditions for hundreds of years.

Scientists have previously attributed these so-called fairy circles — which can extend for hundreds of square miles — to grazing ants, poisonous plants, or toxic gases released from the ground. Locals say they're the work of supernatural forces.


But as Ed Yong explains over at National Geographic, these circles may be caused by industrious termites looking to reshape the landscape:

The circles, according to [Norbert Juergens], are water traps created by a sand termite. The termites eat all the grass within a circular patch, exposing underlying sand grains that store any falling rainwater. These barren freckles are works of ecological engineering, designed to retain precious water in an otherwise dry land. They’re like desert versions of beaver dams.

This process, argues Juergens, also drives wider benefits: the termites become a valuable food resource for a host of other animals such as geckos, moles, aardvarks, jackals, spiders, and ants.

Read the entire study in Science. And check out Ed Yong's entire article; not everyone is convinced that Juergens is right.


Images: Norbert Juergens.

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