Global Fairy Circles: Mystery Solved with Satellite Imagery & AI

The mesmerizing natural phenomenon known as fairy circles - barren patches of soil, free from vegetation and evenly spaced - has captivated our curiosity for years. A recent global map, constructed from satellite imagery, has discovered these enigmatic circles in no less than 263 locations worldwide, indicating their global prevalence far exceeds prior assumptions. 

What are Fairy Circicles?

Fairy circles, encompassed by tall grass rings, are circular areas of barren soil, devoid of any plant life. These peculiar "voids," ranging from 2 to 20 meters in diameter, pepper the desert grasslands of Namibia, and have been discovered in Australia, specifically east of Newman town in the Pilbara region. The distinct characteristics of the two primary locations of fairy circles have complicated the explanation of their origin. 

Theories Behind Fairy Circles: Termites or Vegetation

The dominant theory assigns their creation to termites, who supposedly feast on grass roots around their nests, seems plausible for Namibian fairy circles but not the Australian ones. While termites were present in about 80% of Namibian fairy circles, they were absent in the Australian circles. Another hypothesis, suggesting that vegetation in these arid zones maximizes scarce water resources by self-organizing to concentrate moisture and compete with distant species, also faces scrutiny due to the differing flora in the two regions.

Understanding the Global Spread of Fairy Circles

While the genesis of fairy circles remains enigmatic, possibly tied to organisms' response to water scarcity, environmental scientist Emilio Guirado from the University of Alicante, Spain, believes that understanding their distribution could shed light on their origin. This approach focuses on commonalities among their locations, rather than their differences.

Utilizing Machine Learning in Fairy Circles Research

Guirado utilized machine learning systems to examine 574,799 land areas of 10,000 square meters globally, identifying 263 locations with fairy circles. These locations are dispersed across 15 countries on three continents, including Namibia and Western Australia, and newly associated regions like the Sahel, Western Sahara, Horn of Africa, Madagascar, Southwest Asia, and Southwest Australia. The study was published in PNAS.

Identifying Common Characteristics of Fairy Circle Locations

The algorithm identified shared characteristics among these locations. Fairy circles typically form in desert-like, arid, and dry environments with high temperatures and seasonal precipitation; coupled with nutrient-poor, sandy soil. This newfound knowledge will be instrumental in future research to decipher the purpose of these formations and whether they can aid vegetation combating climate change effects.