Mystery of 'fairy circles' in African desert finally explained...

 

...and the answer lies hidden underground...

For decades it is a phenomenon which has left scientists stumped.

Thousands of barren patches of land several metres wide, known as 'fairy circles', which are found across the Namib desert in southern Africa for no apparent reason.

Theories have included radioactive soil, meteorites or even UFOs while local myth holds that a dragon lives beneath the Earth and his fiery breath burns the vegetation. 

Thousands of the mysterious fairy circles are found throughout the Namib desert in Namibia and Angola

A number of theories have been suggested to explain the fairy circles including meteorites and radioactive soil.

But finally, a German professor believes he has solved the mystery for good.

After a six-year study, and more than 40 trips to the Namib desert, Norbert Jürgens from the University of Hamburg says a species of sand termite is responsible.

 He examined hundreds of fairy circles in more than 1,200 miles of the desert and found that the Psammotermes allocerus, or sand termite, was the only species consistently present.Mr Jürgens theory is that they eat plant roots before they can sprout through the desert soil creating a water trap - in a similar way that beavers create dams.Because of the lack of foliage, rainwater is not lost through transpiration (the evaporation of water from plants) and instead stays below the surface.

This allows the sand termites to survive and stay active during the dry season and also helps grasses at the edge of the circle to thrive attracting other life forms.The termites feed on those grasses, thereby gradually extending the circle.

Mr Jürgens concludes that the fairy circles are actually an astounding example of ecological engineering by the sand termite, designed to retain precious water in an otherwise arid landscape.

'Fairy circles can be regarded as an outstanding example of of allogenic ecosystem engineering resulting in unique landscapes with increased biodiversity, driven by key resources such as permanently available water, perennial plant biomass, and perennial termite biomass,' he told South Africa's newspaper the Weekend Argus.

'The termites match the beaver with regard to intensity of environmental change, but they surpass it with regard to the spatial dimension of their impact.

'The sand termite turns wide desert regions of predominantly ephemeral life into landscapes dominated by species-rich perennial grassland, supporting uninterrupted perennial life even during dry seasons and drought years.'

Steve Robson