By Sarah Romero
The so-called ‘fairy circles’ of the Namibian desert (Africa) are barren areas that are curiously surrounded by perennial vegetation and can reach up to 35 meters wide. But what is the origin of these strange formations?
The pattern of these circles is characterized by their regular spacing and hexagonal distribution. Despite the fact that regular vegetation patterns are frequent in nature, the scientific community does not agree on the motivation behind them. The truth is that there are several hypotheses about them.
The first one speaks of the fact that we must look for the origin in that plants help the growth of the vegetation closest to them and, on the contrary, compete with the more distant species, hence the curious patterns observed in satellite images. The second hypothesis suggests that termites, ants or rodents are responsible.
Well, according to the study carried out by the department of Ecology and Evolutionary Biology at Princeton University (USA) and published in the journalNature, both hypotheses are valid. When reconciling both perspectives through simulation models, they verified that both sand termites (Psammotermes allocerus) as the vegetation converge in the emergence of the famous fairy circles; that is, the two make up a joint cause of these regular and self-organizing patterns. The research was validated thanks to field data from four continents: Africa, North America, South America and Australia.
Termites (according to a study published inScience in 2013) devour vegetation that follows intermittent desert rains, which is why circular barren areas appear. But, due to the rapidity of filtration and the lack of evapotranspiration, they also retain water. The conclusion of this whole process is the formation of circles of perennial vegetation, the 'fairy circles'.