Fairy circles, those mysterious patterns in grasslands found, until now, only in Africa, have been discovered in Australia.
Dr Stephan Getzin from the Helmholtz Centre for Environmental Research came to Australia from Germany to investigate reports of fairy circles near Newman in the Pilbara in Western Australia.
He found a remarkable match between the patterns of Australian and Namibian fairy circles.
The cause of the vegetation-free circles and patterns have been hotly debated. Some of the circles measure only a few metres, others reach up to 20 metres in diameter. Most of them have a lush peripheral growth of grass.
Theories that they were created by terminates or by gas leaking through the soil have recently been discarded in favour of the cause being resource-competition for water among plants.
“Vegetation gap patterns in arid grasslands, such as the fairy circles of Namibia, are one of nature’s greatest mysteries and subject to a lively debate on their origin,” writes Getzin and his co-authors in the journal PNAS.
After researching the Australian fairy circles, Getzin says the patterns emerge by self-organisation with no correlation with termite activity.
“For a long time, ecologists weren’t convinced that plants in dry areas could organise themselves because the theoretical principles for these processes lie in physics,” says Getzin. “But it has since become increasingly clear how important this process is.”
In Namibia there are usually two to three species of termite or ant scuttling around, bringing rise to speculation about the cause of the circles.
But the situation in Australia is clearer. “There we found in the majority of cases no nests in the circles,” says Getzin. “And the ones we did find have a completely different distribution pattern to the fairy circles.”
For him this is a clear indication that the barren patches are not produced by animal activities but the way in which the plants organise themselves.
Getzin believes it is likely that there are as yet unknown fairy circles in other dry and sparsely inhabited regions of the world.
Here are some different types of fairy circles in the Pilbara: