One of nature’s greatest mysteries has been spotted in the Australian outback. And the discovery could help solve the puzzle.
Circular barren patches, known as “fairy circles”, have been found throughout the red-soiled Pilbara region of Western Australia.
Until now, these patches of bare Earth had only been seen in the Namibian desert, stretching from South Africa to Angola.
The cause has long baffled scientists. Floated theories include termites nibbling at grass roots, a build-up of toxic gas and competition between plants for limited water.
The discovery of the circles in Australia has allowed experts to discount some of these theories.
Australia’s ‘fairy circles’ vary between four and seven metres in diameter [Image: Dr Stephan Getzin]
Dr Stephan Getzin, an ecologist at the Helmhotlz Centre for Environmental Research, and his team took water samples and recorded animal activity in the area.
“We found in the majority of cases no nests in the circles and unlike in Namibia, cryptic sand termites do not exist in Australia,” Dr Getzin explains.
“And the ones we did find have a completely different distribution pattern to the fairy circles.”
Instead, Dr Getzin suggests the circles may be caused by the way plants organise themselves.
If not protected by vegetation, the Australian soil is backed onto a hard crust and water struggles to penetrate the ground – meaning it flows away, leaving patches where plants cannot germinate.
The ‘fairy circles’ in Namibia [Image Michael Fay]
As for southwestern Africa, Dr Getzin believes a similar but different phenomenon is taking place.
“In Namibia, the sandy soils of the fairy circles are much more permeable and precipitation can drain away with ease.
“The details of this mechanism are different to that in Australia. But it produces the same vegetation pattern because both systems of gaps are triggered by the same instability.”