The truth is out there… in Namibia. Inhabitat previously reported on the mysterious “fairy circles” that have appeared without explanation in the Namib Desert for millennia. Over the past several decades, scientists have sought to uncover what exactly is causing this mysterious phenomenon. Although recent theories have centered on local termites, scientists had been unable to determine how exactly these creatures created the fairy circles over such a wide range range. The most recent explanation points to aggressive desert plants that fill ecological gaps left by colonizing termites.
The fairy circles appear as patches of barren land between seven and 50 feet in diameter that are defined as circular by a ring of prominent grass growth around the edge. Until recently, this was thought to be a uniquely African phenomenon. However, similar examples have been found in the Pilbara region in Western Australia. According to myths of the local Himba people, the fairy circles were created by Mukuru, their original ancestor, or are footprints of the gods. Some local tour guides also promote the legend that the circles are created by a dragon, whose poisonous breath kills the central vegetation.
Ecologists at Princeton University used computer models to test the termite hypothesis, which posits that sand termites eat the roots of low-laying vegetation and allow for more moisture below the surface and barrenness above. In the computer simulations, the mounds only formed where termite colonies of similar size confronted each other and settled on a border. “The termites start with their own mound and go out and forage,” said Princeton researcher Corina Tarnita. “If they find a smaller colony, they simply kill it and expand their own territory. But if they run into a colony that is about the same size, they cannot do that, and end up with a boundary where there’s permanent conflict, but not a full-blown war.”
Tarnita’s updated computer model took into account the natural competition that exists between desert plants. While rooted desert plants can initially provide shade and moisture for other plants, they eventually spread, pulling more water for themselves and away from more distant plants. “You find a much smaller scale pattern that’s driven by the plants self-organising in response to water,” Tarnita said. Although the researchers do not claim to have a definitive explanation of the fairy circles, their computer models seem to provide the most likely explanation. “We get a much more complete description of the patterns.” The fairy circles may appear to be supernatural, but their existence is a result of identifiable natural forces. “One of the most striking things about nature is that despite the complexity of all of its interactions and the many processes that act simultaneously, sometimes, and more often than we expected, you find these amazing regularities.”
Via the Guardian