The fairy circles (circular barren patches) of the Namib Desert - What do we know about their cause 50 years after their first description?

•Since the first description of the fairy circles 50 years ago, the cause is still hotly debated.•The first review paper in nearly 20 years on the fairy circles of the Namib Desert.•The contrasting main theories on the formation and maintenance of fairy circles are discussed.•The physical characteri...

Full description

Saved in:
Bibliographic Details
Published in:South African journal of botany 2021-08, Vol.140, p.226-239
Main Authors: Meyer, J.J.Marion, Schutte, C.S., Galt, N., Hurter, J.W., Meyer, N.L.
Format: Article
Language:English
Subjects:
allelopathy
Barren circular patches
Fairy circles
Namib desert
plant-plant interactions
Plant-soil interactions
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:•Since the first description of the fairy circles 50 years ago, the cause is still hotly debated.•The first review paper in nearly 20 years on the fairy circles of the Namib Desert.•The contrasting main theories on the formation and maintenance of fairy circles are discussed.•The physical characteristics of fairy circles are described and critically reviewed. Since they were described for the first time 50 years ago, more than 30 peer-reviewed papers have been published on a number of extremely diverse theories as the cause of the formation of hundreds of thousands of nearly circular barren patches (fairy circles) found in southwestern Angola, Namibia and northwestern South Africa. However, scientists interested in finding an explanation for the cause and maintenance of these fairy circles in the driest parts of the world are still without agreement on the true reason(s) behind this intriguing phenomenon. In this review we firstly present the four main theories and explain their hypotheses on the formation and/or maintenance of fairy circles. Secondly, we summarise the previously described physical characteristics of the fairy circles, e.g. soil substrate, moisture content, shape, size, lifespan, dynamics and spatial patterning, and then present the supporting evidence as published by the proponents of the theories on vegetation self-arrangement, insects/ants, gas and Euphorbia allelopathy, as the causative drivers of this natural phenomenon. We also present the critical views of scientists on the theories they are not supporting.
ISSN:0254-6299
DOI:10.1016/j.sajb.2021.04.008