Namibia: The eastern boundary of the Namib Desert is home to tens of thousands of ‘fairy circles’ – barren patches within the grassland. Scientists are still unsure what causes fairy circles, but a paper published in Public Library of Science ONE described the life cycle of the formations, using both field data and satellite images. The satellite photographs provided the data for estimating fairy circle life span.
Walter Tschinkel, a biologist at Florida State University, US, compared satellite images of the circle-strewn area in 2004 with images from 2008, noting whether the formations were present in both years and what changes had occurred in size, shape or vegetation. He also studied ground photographs of circles and images from Google Earth for a more detailed look at the sizes and locations of circles as well as how they changed over time.
Previous research had indicated that the fairy circles were not static, but Tschinkel’s work was the first to document the details of the life cycle: birth, maturation, enlargement and death—or revegetation. His paper described the different phases and estimates the life span of a fairy circle to be 23 to 75 years, depending on size.
Tschinkel’s work does not answer the question of why fairy circles appear, but it helps to pin down the processes researchers will need to study to solve that mystery. “Every good piece of science starts with a good description of the phenomenon, and that’s what I’ve provided here,” he said.
Source: Scientific American