Mysterious African Fairy Circles Are 'Alive'

[Jeff]

by Rachel Nuwer on 27 June 2012, 5:00 PM

Walter Tschinkel may not have solved the mystery of the fairy circles, but he can tell you that they're alive. Tens of thousands of the formations—bare patches of soil, 2 to 12 meters in diameter—freckle grasslands from southern Angola to northern South Africa, their perimeters often marked by a tall fringe of grass. Locals say they're the footprints of the gods. Scientists have thrown their hands up in the air. But now Tschinkel, a biologist at Florida State University in Tallahassee, has discovered something no one else has.

...

By comparing photos taken over a 4-year period, he confirmed something other scientists had suspected: The circles were alive—or at least they were dynamic. A number of circles appeared and disappeared over this time period. Extrapolating from the data, Tschinkel calculated that most smaller circles arise and vanish every 24 years, whereas larger circles last up to 75 years. Overall, the lifespan averaged 41 years.

To confirm his results, Tschinkel crunched data collected from the NamibRand Nature Reserve. Over the past 10 years, the park has sold fairy circles to ecotourists for about $50 each. The buyers don't actually get the land; they just adopt it—kind of like people who "purchase" stars. Each circle the reserve sells is marked with the date of sale, and new owners are given the latitude and longitude so they can check up on their purchase on Google Earth.

Tschinkel's friends at the reserve revisited the sold fairy rings and took photos to estimate the amount of regrowth that had occurred over the years. From the number of fairy circles that had died or started to die over the past 2 to 9 years, Tschinkel calculated that the fairy circles had an average age of about 6 decades. "It gives me some confidence that we really are talking about a lifespan of about 30 to 60 years," he says.

...

http://news.sciencemag.org/sciencenow/2 ... e-ali.html

[Hammer of Los]

...

I thought fairy rings needed mushrooms.

I know of one such ring.

I have often been tempted to pace around it widdershins, in order to summon the faerie folk, the tuatha de danaan.

Or rather, to mysteriously enter their world.

Except I think I already did.

...

[Jeff]

...

I thought fairy rings needed mushrooms.

Me too, but the fairies of the Southwest African rings think different. There's a gallery of photos here.

[seemslikeadream]

...

I thought fairy rings needed mushrooms.

I know of one such ring.

I have often been tempted to pace around it widdershins, in order to summon the faerie folk, the tuatha de danaan.

Or rather, to mysteriously enter their world.

Except I think I already did.

...

THE HISTORY OF THE TUATH-DE-DANAANS

Iod na laimh lith gan ghuin
Iod na beorl gan ean neamhuib,
Iod na foghlama gan ean ghes,
Is iod na lanamh nas

it's fly time...

beyond the silent rocks..
still the dream

[Burnt Hill]

I know the "fairy rings" can remain after the bloom, or fruiting, and then can bloom again.
I have a couple of rings in the front yard-that havent bloomed in a couple of years-at least that I have noticed.
On Edit: Yea, mine are the traditional type- 8's and 0's, nothing like the ones in The pics from S. Africa.

[Iamwhomiam]

I know certain plants grow outward, in a circle. As the parent plant dies and disintegrates, all that's left is a circle. The oldest living thing on earth is reported to be a creosote plant growing somewhere in the US southeast, though I cannot recall how large in diameter was, but I do recall that it was very large indeed.

But then again, they could be sauce landing sites, no?

[Burnt Hill]

I know certain plants grow outward, in a circle. As the parent plant dies and disintegrates, all that's left is a circle. The oldest living thing on earth is reported to be a creosote plant growing somewhere in the US southeast, though I cannot recall how large in diameter was, but I do recall that it was very large indeed.

But then again, they could be sauce landing sites, no?

If the sauce really boils over, then maybe.

[Joe Hillshoist]

I know certain plants grow outward, in a circle. As the parent plant dies and disintegrates, all that's left is a circle. The oldest living thing on earth is reported to be a creosote plant growing somewhere in the US southeast, though I cannot recall how large in diameter was, but I do recall that it was very large indeed.

But then again, they could be sauce landing sites, no?

Antarctic Beech trees grow in circles.

[Burnt Hill]

http://www.livescience.com/28268-fairy-circle-mystery-solved.html
Found this link through Accuweather.
Sand Termites.
And the sun will shine in upstate NY tomorrow, believe it or not.

[Iamwhomiam]

Yes Joe, many trees grow like that but it is caused because the parent tree that had occupied the center before dying threw out new growth from the roots or from seeds that fell around it.

Thanks for posting, Burnt Hill.
I caught the story yesterday on NPR, very interesting. The termites bite off the roots, pushing the circle outward.

[Joe Hillshoist]

Thats right. Those trees are suckers. Very old suckers tho.

They do grow outwards tho, like traditional fairy rings that are caused by fungi.

[Iamwhomiam]

^^^ Right. Some friends of mine who hunt always meet at the "Octopus Tree," an ancient white birch that grew out suckers as the parent rotted away. Now also ancient, most encircling the now disappeared parent are rotting, too.

[seemslikeadream]

FEBRUARY 22, 2019
Researchers get to the bottom of fairy circles
by University of Göttingen

Researchers get to the bottom of fairy circles
Excavations in a fairy circle. Three of the co-authors of the study are Dr Todd E. Erickson, Dr Hezi Yizhaq and Dr Miriam Muñoz-Rojas (from left to right). Credit: Stephan Getzin
Fairy circles are round gaps in arid grassland that are distributed very uniformly over the landscape and only occur along the Namib Desert in southern Africa and in parts of Australia. Various theories circulate about the actual cause of these unusual spatial patterns, ranging from poisonous Euphorbia plants or rising gases, to ants, termites or plant competition for sparse water resources. Scientists from the University of Göttingen, Australia and Israel have now got to the bottom of their cause with soil investigations and drones. The results suggest that the fairy circles in Australia were caused by processes such as the weathering of the soil by heavy rainfall, extreme heat and evaporation. The extensive data collected by the researchers argued against a causal relationship to underground termite structures.


So far, fairy circles are only known from southwestern Africa around the Namib Desert and from Western Australia near the miners' town of Newman. While the origin of Namibia's fairy circles has been puzzled over since the early 1970s, the Australian fairy circles were only discovered in 2014. Despite a distance of around 10,000 kilometers, both occurrences have an identical spatial pattern, which makes them direct "relatives."

Supported by the German Research Foundation (DFG), the scientists dug a total of 154 holes in 48 fairy circles east of Newman over a length of 12 kilometers in order to assess the possible influence of termites objectively and systematically. With the help of drones, they mapped areas of 500 by 500 meters to compare typical fairy circle gaps with typical vegetation gaps, such as those caused by harvester termites in large parts of Australia. In addition, they investigated the soil conditions in the area of the fairy circles and in adjacent reference areas, where no grass grows over large areas.

Researchers get to the bottom of fairy circles
The fairy circles seen from the air. They form an additional source of water in this arid region, because the rainwater flows towards the grasses on the edge. Credit: Stephan Getzin
"The vegetation gaps caused by harvester termites are only about half the size of the fairy circles and much less ordered," explains Dr. Stephan Getzin from the University of Göttingen. "And in most cases, we didn't even find any hard subterranean termitaria that elsewhere in Australia prevent the growth of grasses."

According to the researchers, however, the high soil compaction and clay content in the investigated fairy circles and vegetation-free reference areas are indications that the fairy circles are formed by abiotic processes such as mechanical weathering of the soil by heavy rain in cyclones, extreme heat and evaporation.

"Overall, our study shows that termite constructions can occur in the area of the fairy circles, but the partial local correlation between termites and fairy circles has no causal relationship," explains Getzin. "So no destructive mechanisms, such as those from termites, are necessary for the formation of the distinct fairy circle patterns; hydrological plant-soil interactions alone are sufficient."



In Namibia, research has so far concentrated on typical fairy circles in homogeneous landscapes. In their pilot study, the scientists focused on extraordinary fairy circles in atypical environments in order to better understand the actual threshold conditions for circle formation. Using Google Earth imagery, they found unusual circles—huge ones more than 20 meters in diameter, chain-like oval ones more than 30 meters long in drainage lines, circles in car tracks and circles in particularly dry, disturbed or Euphorbia-rich areas.

"Here, our soil moisture studies showed that under such varied conditions, the fairy circles function less as water reservoirs than under typical homogeneous conditions where they are extremely well ordered," says Getzin. With this work, the scientists intend to open up a new thematic field, as they hope to gain further insights into the formation and persistence of the fairy circles from studying "extraordinary" fairy circles.

https://phys.org/news/2019-02-bottom-fairy-circles.html

It’s not termites: new study gives fresh take on how “fairy circles” form
Odd circular gaps in grassland growth likely due to resource competition. Or dragons.

Jennifer Ouellette - 2/25/2019, 6:55 AM
The fairy circles in Namibia seen from the air. New research asserts they form an additional source of water in this arid region, because the rainwater flows towards the grasses on the edge.
Enlarge / The fairy circles in Namibia seen from the air. New research asserts they form an additional source of water in this arid region, because the rainwater flows towards the grasses on the edge.
Stephan Getzin
Himba bushmen in the Namibian grasslands have passed down legends about the region's mysterious "fairy circles"—bare, reddish-hued circular patches dotted along the 1200-mile long swath of land. They can be as large as several feet in diameter. Dubbed "footprints of the gods," it's often said they are the work of the Himba deity Mukuru, or an underground dragon whose poisonous breath kills anything growing inside those circles.

Scientists have their own ideas, and over the years two different hypotheses have emerged about how the circles form. One theory attributes the phenomenon to a particular species of termite (Psammmotermes allocerus), whose burrowing damages plant roots, resulting in extra rainwater seeping into the sandy soil before the plants can suck it up—giving the termites a handy water trap as a resource. As a result, the plants die back in a circle from the site of an insect nest. The circles expand in diameter during droughts because the termites must venture further out for food. The other hypothesis holds that the circles are a kind of self-organized spatial growth pattern arising as plants compete for scarce water and soil nutrients.

Two new papers, one published in the journal Ecosphere and the other in the Journal of Arid Environments, add yet another dimension to the ongoing debate. The authors argue that—at least in northwestern Australia, where fairy circles were first observed in 2014—termite activity may be present at such formations, so there's some correlation in the data. But termites aren't causing the fairy circles. The authors attribute the circles' emergence to natural weather-related processes like heavy rainfall, extreme heat, and evaporation. These events deplete the soil of nutrients, forcing plants to compete for scarcer resources to survive.

"No destructive mechanisms, such as those from termites, are necessary for the formation of the distinct fairy circle patterns."

"Overall, our study shows that termite constructions can occur in the area of the fairy circles, but the partial local correlation between termites and fairy circles has no causal relationship," said co-author Stephan Getzin of the University of Gottingen in Germany. "So no destructive mechanisms, such as those from termites, are necessary for the formation of the distinct fairy circle patterns; hydrological plant-soil interactions alone are sufficient.”

Roots of a controversy

Biologist Walter Tschinkel of Florida State University concluded in 2012 that the circles had an average lifespan of 41 years, based on his analysis of satellite images over many decades. He thought termites were the most likely explanation but found no evidence to support his hypothesis. The following year, ecologist Norbert Juergens of the University of Hamburg reported evidence of an especially clandestine nocturnal species of sand termite (Psammmotermes allocerus) that could be the culprits, based on his sampling of around 1,200 fairy circles from his many trips to Africa.

That didn't quite convince others, in part because the termite hypothesis doesn't account for why the fairy circles eventually disappear. That same year, Michael Cramer of the University of Capetown—who describes himself as a "plant ecophysiologist"—published a paper arguing that the circles are the result of self-organized spatial patterning, typical of how plants compete in resource-scarce environments like the arid grasslands of Namibia.

Excavations in a fairy circle in northwestern Australia by three co-authors of two new studies seeking to explain their formation: (l to r) Todd Erickson, Hezi Yizhaq, and Miriam Muñoz-Rojas.
Enlarge / Excavations in a fairy circle in northwestern Australia by three co-authors of two new studies seeking to explain their formation: (l to r) Todd Erickson, Hezi Yizhaq, and Miriam Muñoz-Rojas.
Stephan Getzin
Cramer built on prior computer modeling work, combining Google Earth images of the fairy circles in Namibia with soil samples from the region to produce a new computational model. That model predicted the distribution of the circles with 93 percent accuracy, and Cramer found that variations in rainfall were the strongest contributing factor in their model. After fairy circles were also discovered in Australia, he argued in a 2016 paper that this was further evidence for the "competition for scant resources" hypothesis.

So who is right? Maybe both, according to a 2017 paper that tried to reconcile these two competing hypotheses with a new computer model combining elements of both. Co-author Corina Tarina, an evolutionary biologist at Princeton University, and several colleagues first ran simulations to mimic the impact of underground termite activity on desert grasses, particularly the effect of neighboring colonies of a similar size that came up against one another. This process results in a kind of stalemate, establishing a border between their territories.

The team next built a computer model that simulated the warring underground termites as well as the natural competition that arises between desert greenery. As the grass grows, there is more competition for precious resources. The long roots must draw water from further away, depriving plants in those more distant areas of water, for instance. Adding that plant competition to the model produced the most similar patterns to the fairy circles. To confirm their findings, the group traveled to Namibia to photograph the fairy circles firsthand and found an exact match, although they didn't claim to have an explanation for how every fairy circle forms.

Now, an international team of scientists from Germany, Australia, and Israel have weighed in with the results of their study of fairy circles in northwestern Australia, near an old mining town called Newman. The team dug over 150 holes in almost 50 fairy circles in the region to collect and analyze soil samples, specifically to test the termite hypothesis. They also used drones to map larger areas of the continent to compare the gaps in vegetation typically caused by harvester termites in the region, with the fairy circles that sometimes form.

"The vegetation gaps caused by harvester termites are only about half the size of the fairy circles and much less ordered," said Getzin of their findings. "And in most cases, we didn't even find any hard subterranean termitaria that elsewhere in Australia prevent the growth of grasses." But they did find high soil compaction and clay content in the circles, evidence for the contribution of heavy rainfall, extreme heat, and evaporation to their formation.

Or maybe it's just subterranean dragons with bad breath.
https://arstechnica.com/science/2019/02 ... cles-form/