The African desert fairy circles mystery has been solved, according to findings from a new study published today in Science magazine.
The fairy circles, thousands of large round patches of barren earth ringed in grass, dot the desert landscape across southwestern Africa. Researchers have sought the exact cause behind the phenomenon for more than four decades. Now, a biologist from Germany may have pinpointed the source — a species of sand termite.
Termites have been considered a possible candidate before. However, a new study by Norbert Juergens, a biologist with the University of Hamburg, has provided the first tangible evidence in favor of the termite theory.
While studying the desert fairy circles mystery Juergens discovered that Psammotermes allocerus, a species of sand termite, was the most common factor associated with the bizarre round patches.
In addition, he found underground tunnels, foraged plant material, and layers of cemented sand within the majority of the desert fairy circles — signature aspects commonly associated with termite life.
The study suggests that the insects may be conducting “ecosystem engineering,” effectively creating a water source within the circles by consuming grass roots and eliminating plant life.
During a six year period, the biologist researched the water content of soil within the fairy circles. Juergens reportedly found the top layers of dirt to contain water in excess of two inches, even during the driest season.
Juergens contends that the absence of grass within the rings allows water to collect inside the circles, rather than being evaporated back into the air through plant life. The study suggests that the moisture trapped inside the soil is enough to sustain the sand termites during time periods when rainwater is scarce.
Jeurgens spoke to BBC News about the implications of the study, marveling at the ingenuity of the sand termites:
“We all admire the beaver for the way it can turn a linear river into a lake with a dam, but the termites turning the desert into a pattern of oases that allow permanent life even in drought periods for hundreds of years – that’s much more fascinating. What is more, these termites do it on a large scale – over hundreds of square kilometers. They should replace the beaver as the text-book engineer.”
Some disagree that the study definitively proves that the desert fairy circles mystery has been solved. Yvette Naude, a chemist from the University of Pretoria in South Africa, contends: “The paper is a useful addition to debating the origin of the fairy circles” but cautions that the research “does not address the key question as to what is the primary factor that causes sudden plant mortality, i.e. the birth of a fairy circle.”
However, findings from the study suggest that the sand termites continue to consume plant roots over an extended period of time — causing, maintaining, and even expanding the barren circles. The patches have been known to measure anywhere between six feet to 50 feet across and can remain barren for up to 60 years.
While scientists continue to debate if the desert fairy circles mystery has been solved, the local Himba people have their own point of origin. They call the circles “the footprints of the gods,” created by their original ancestor, Mukuru.
[Top and bottom images via Wikipedia]