Conservationist axed to death in Hwange, Zimbabwe

A conservationist working with endangered painted dogs near Zimbabwe's Hwange National Park has been found battered to death in his cottage, friends said on Thursday.

Gregory Gibbard, an Australian who had worked for some time as an administrator for Painted Dog Conservation, was axed to death on Tuesday night, a friend told News24.

"He was hit twice in the head apparently, with what sounds to have been an axe," the friend, who asked not to be identified, said in a telephone interview.

"It is assumed that the motive was robbery but this kind of attack is excessively unusual in Zimbabwe," he added.

Gibbard's cottage is located near Hwange airport, just outside Hwange National Park, which is in the west of Zimbabwe.

Police are understood to be investigating but there are no reports of arrests so far.

Painted Dog Conservation said in a brief statement: "It comes with great sadness that we need to inform you that one of our founding PDC Inc members and friend Greg Gibbard... was tragically murdered on Tuesday night at the project headquarters."

‘Tragic’

Friends took to Facebook to express their shock at Gibbard's murder.

"Goodbye my dear friend. So sorry. Wish we had a chance to have spoken one more time," said Colin Yapp.

Sharon Stead wrote: "Absolutely tragic - his death has rocked the Hwange community."

Painted dogs are also known as African wild dogs. They are among the continent's most endangered wildlife species.

In its February newsletter Painted Dog Conservation spoke movingly of the links forged between the NGO and the local community, whose head was only identified as Chief Nelukoba. Fifty members of the community have recently volunteered to be part of anti-poaching and anti-snaring patrols, the newsletter said.

"Painted Dog Conservation has been operating there for a long time," Gibbard's friend confirmed on Thursday.

Source: Conservationist found axed to death in Zimbabwe (09/04/15)

Mystery of the Namib Fairy Circles continues

Source: Mystery fairy circles defy explanation

Viewed from the skies, the Namibian desert looks like the surface of a wild and desolate planet. There are no obvious plants, and thousands of tiny craters dot the red barren earth. But zoom in a little closer and a different picture emerges: patches of green appear, along with the occasional tree, and, eventually, perfect rings of tall, sometimes lush, grass come into focus, each one enclosing a plate of bare-hollowed out earth.

These grass-ringed patches are the fairy circles of Namibia. For centuries they’ve entranced the local bushmen, the Himba. One oral myth says the circles are the footprints of the gods; another that a dragon living beneath the earth’s crust breathes fiery bubbles which, when they hit the surface, burn the vegetation into the near-perfect circles.

But the circles haven’t just confused the Himba. Despite decades of investigation, and a multitude of theories, scientists still haven’t come up with a definitive explanation for their existence. To this day, the circles remain one of nature’s greatest mysteries.

A thousand unblinking eyes

Perhaps the fairy circles wouldn’t have been able to guard their secrets so successfully if they hadn’t been so concentrated in a region referred to as “The land God made in anger.” The circles occur in millions in a band where the arid grasslands transition to desert, a 1,800km-long strip extending southward from Angola to the Northwestern Cape province of South Africa. Most of them, however, flank the red sands of the Namib desert, a remote and harsh environment.

Scattered across the landscape, never overlapping, the circles gaze silently up at the sun like a thousand unblinking eyes, oblivious to the harshness of their surroundings. A tall ring of grass surrounds the barren centres, which can measure between two and 20 metres in diameter. The lush periphery of each dish stands at knee height, dwarfing the scrubby grasses between the circles, seemingly standing guard to protect them from incoming vegetation.

“There are a few key things that any science theory has to explain about fairy circles,” says Michael Cramer, a plant physiologist at the University of Cape Town, South Africa. “Why are they circular and barren and why are they regularly spaced from each other?”

But since the 1970s, when researchers first started investigating the phenomenon, no single theory has yet managed to do that. At least not to the satisfaction of the scientific community.

But this failure is not for want of trying, or desire.

“There is a tremendous sense of excitement that there is something really interesting going on and we want to know what that is,” says Professor Don Cowan, director of the Centre for Microbial Ecology and Genomics at the University of Pretoria, South Africa. “It is a desire to understand the system. What is going there? What is happening?”

Fairies run rings around scientists

“They are really neat places, these little clean patches,” says Walter Tschinkel, a biologist at Florida State University. “They are like little satellite dishes.” When Tschinkel, the biologist from Florida, first saw the fairy circles on a visit to the NamibRand Nature Reserve in southwestern Namibia, he knew right away what was causing them. "I looked at them and thought ‘this has to be termites,’” Tschinkel says. “It is the sort of things termites do.”

Tschinkel dug for termites in one or two circles and returned in 2007 to investigate, and hopefully prove, his hypothesis. “It took us about three days to establish, without a doubt, that termites were absolutely nothing to do with this,” Tschinkel says.

Tschinkel’s theory proved to be just one of the many to hit the Namibian dust. Scientists have ruled out poisoning from toxic indigenous plants, milk bushes that produce toxic latex, and also contamination from radioactive materials. They have also rejected the idea that the ostriches created the circles by bathing in the dust.

Some theories are still holding strong though, and Cowan jokes that each scientist sees the solution in terms of their own particular area of expertise: the insect biologists think the circles are created by ants or termites, the plant physiologists think it’s grasses, and the chemists think it’s gases. Cowan, a microbial ecologist, proves no exception.

“Once we saw them, we immediately thought, ‘it has got to be microbial ecology,’” Cowan says, meaning, in layman’s terms, that means he believes that microorganisms have been killing the plants inside the circle.

The fact that the circles are round, start off small and grow large is entirely compatible with the presence of a pathogenic organism, such as a fungus, Cowan says. Fungal strands, or mycelium, would spread outward radially, infecting the roots of plants and causing them to die. Once the fungus establishes itself in the circle it infects new grass seeds preventing them from growing, creating the barren interior.

“It is just a hypothesis,” Cowan says. But it’s more compatible with the evidence than many other theories, he adds.

It is like panning for gold. Once in a while you find a little flake or a nugget and sometimes it is fool's gold.

Another theory is closer to the folklore; a team of chemists from the University of Pretoria propose that gas released from underground may be killing off the plants in the circular patches. They just don’t suggest this gas comes from the mouth of an underground dragon.

The scientists worked out this theory when they collected soil samples from inside the fairy circles and planted seeds inside them. The seeds didn’t last for long, and neither did seeds planted directly in the centres themselves. The bare soil, the scientists concluded, provides the real clues. Chemical analysis revealed that natural gas seeping to the surface could be killing the plants. Once the gas finds an outlet it spreads radially outward in a spherical shape destroying grasses in a near perfect circle.

However, yet another recent theory proposes that grasses competing for water and nutrients - limited resources in the Namib desert - create the circles, explaining why they never overlap. When Cramer examined precipitation levels and seasonal temperatures, he found that the occurrence of fairy circles appears to be restricted to particularly arid zones right at the transition from grassland to desert regions.

Go west into more arid regions and the circles disappear, go east into the wetter mountains and they vanish. “So it is a very narrow band in Namibia where the conditions are just right,” Cramer says.

In these regions, where both rainfall and nutrient levels are low, grasses have to compete for resources. Hardier grasses suck up all the water and nutrients leaving the neighbouring vegetation to die. The gap between vegetation gets larger until eventually water and nutrients pool and collect in the centre like an oasis. Then, larger grasses grow around the pool, sucking out the water and creating a fairy circle.

Tschinkel believes that this theory accounts for all the characteristics of fairy circles, but since his first visit he has been busy testing out theories. He’s added zinc to the fairy circles and replaced the soil with other fertile soil only to find the same results as the Pretoria chemists: nothing grows in the circles.

If there were an award for the time spent examining fairy circles, the prize would surely go to Norbert Jürgens, an ecologist at the University of Hamburg in Germany. By 2013, Jürgens had completed 40 field trips and sampled about 1200 fairy circles, testing the soil and noting the vegetation and organisms present.

Jürgens found only one organism lay within the circle boundaries, in nearly all the circles. And it was the type of animal originally suspected by Tschinkel; a termite, specifically the sand termite Psammotermes allocerus.

“So the answer to the criminal question: Who did it?” Jürgens says. “There was only one suspect at each crime site. That was the sand termite.”

The soil-living termites feed on the roots of plants killing them, and then, because no vegetation sucks up the rainwater, water pools below the sandy soil, Jürgens says. This soil water supply allowed the termites to survive during the dry season and also helped the grasses on the periphery of the circle to thrive.

Jürgens published his findings and theory in the prestigious journal Science in 2013 and the ensuing media fanfare dubbed the mystery as “solved.”

But other scientists aren’t so sure. “It is the classic mistake of confusing correlation with causation,” Tschinkel says. “There was a high correlation of sand termites in fairy circles but that is not evidence that they are causal.”

The termite theory cannot explain many of the traits of fairy circles, Tschinkel says, including that the circles have a perimeter of tall grass and reside only on sandy soils in a certain range of rainfall.

Other researchers question the theory on different grounds, many unable to find termites consistently in the circles. "The termites are just not there," Cramer says.

The circles compete with one another and space themselves apart from the circles around them.

Among the skeptics is Stephan Getzin, an ecologist from the Helmholtz Centre for Environmental Research, in Leipzig, Germany. As an undergraduate in the 1990s, Getzin had investigated the termite theory but he’d convinced himself that, not only were termites not the cause, but that scientists needed to take a different approach to the problem.

“We’ve had analysis of the soil in labs and we’ve had people digging in the soil but neither has solved the mystery so far,” Getzin says. “Field studies seem unable to solve the problem at this moment.”

And the approach that Getzin took cast a whole new perspective on the puzzle.

Fairies dancing in formation

Scientists had looked underground for gas and dug in the soil for termites and microbes but Getzin wanted a bird’s eye view of the challenge. For that he looked at multiple Near InfraRed orthophotos - aerial images that provide an exact geometrical perspective, similar to a map.

In these images Getzin closely inspected not the circles themselves, but the way they lay across the landscape. And he stumbled across a hitherto unknown feature of fairy circles: they dance in formation.

Are scientists any closer to solving the enigma?

Instead of being simply scattered like a collection of dropped coins, the circles lie regularly spaced from one another. Moreover, this patterning remains the same across the landscape.

“It’s a very consistent regular pattern,” Getzin says, “and it is very homogenous at large spatial scales.”

This regular spacing isn’t so unusual in nature. In other regions of Africa, tiger bush - alternating bands of shrubs and bare earth - run parallel to the contour lines of hillsides, in a marked striped pattern. In Australia, burette-like clumps of spinifex grass dot the desert - like fatter, less elegant cousins of fairy circles.

They almost function like an organism

Both these phenomena are caused by arid conditions. When water and nutrients are scarce, plants compete and “organise” themselves sufficiently far from other plants in an arrangement that best conserves resources.

Drawing from these examples, Getzin proposes a similar mechanism lies behind the shape and regularity of the fairy circles. It’s an answer that agrees with Cramer’s competing grass theory.

“The circles compete with one another and space themselves apart from the circles around them,” Cramer says. “They almost function like an organism.”

Creating these patterns over such large scales requires very consistent conditions - like those in the Namib desert, Cramer says. “The park I work in is a sand plain of about 25km across and I think you'd be hard pressed to find any variation across that at all,” Cramer says. “Nutritionally, hydrologically, topologically it is very uniform. “

The finding also calls into question other theories. “Based on all the knowledge that is currently existing those patterns cannot be caused by social insects or gas leakage,” Getzin says.

So is this finally the end of the mystery?

Getzin is cautious. “What we have done is reopened the whole discussion because we can say with confidence that the termite hypothesis is very unlikely,” he says.

Getzin plans to get funding to have an unmanned aerial vehicle (UAV) fly over the circles in the NamibRand reserve every month. Swooping low, the UAV could record the landscape in greater detail than previously possible.

Such a perspective could reveal other, previously unknown secrets of the circles.

“I’m sure this is not the end of the story,” Getzin says.

Source: Mystery fairy circles defy explanation

Powerlines divide animal populations through UV emissions

Wild animals see overhead electrical powerlines as disturbing lines of flashing lights, which could explain why many species avoid electricity pylons to the point where their natural territories become seriously fragmented, scientists have discovered.
A study of wild reindeer in Norway has shown that they can see overhead power lines in the dark because their eyes are sensitive to the flashes of ultraviolet light which are invisible to the human eye but are constantly being emitted by high-voltage electrical transmission, the researchers said.
Many other species, from birds in the Arctic to elephants in Africa, can also see ultraviolet radiation which may explain why different kinds of animals in widely varying habitats all tend to avoid overhead power lines even though they are considered to be inert and invisible to wildlife, they said.
“Reindeer see deep into the UV range because the Arctic is especially rich in UV light. Insulators on power lines give off flashes of UV light,” Professor Jeffery said. “The animals potentially see not just a few flashes but a line of flashes extending right across the horizon. This is the first bit of evidence that explains why we think they are avoiding power lines,” he said.
Scientists have known that many animals avoid power lines to the point that it sometimes causes their populations to fragment into separate habitats. But until now the observation could not be easily explained, especially as the avoidance goes on for many decades after the power lines were first erected.
Source: Powerlines disturb animal habitats by appearing as disturbing flashes of UV light invisible to the human eye The Indepedent (12/03/14)

Tigerfish predating on swallows in mid-flight

African tigerfish have been filmed by scientists catching swallows in flight.

Some species of fish are known to feed on stationary birds but experts say this is the first evidence of one catching birds on the wing.

Tigerfish are a predatory freshwater species that are best known for their large, razor-sharp teeth.

The behaviour was filmed at Schroda Dam, a man-made lake in Limpopo Province, South Africa.

Researchers from the Water Research Group of North West University, South Africa, described their findings in the Journal of Fish Biology.

"The African tigerfish is one of the most amazing freshwater species in the world," said Prof Nico Smit, co-author of the study.

"It is a striking fish with beautiful markings on the body, bright red fins and vicious teeth."

The fish, Hydrocynus vittatus, is known as a voracious predator and according to Prof Smit, its characteristic jump makes it a favourite species for freshwater anglers.

It is a protected species in South Africa and Prof Smit and colleagues were conducting a study into how it uses different habitats in Schroda Dam.

Using radio tags to monitor the movements of individual fish, researchers found that they primarily fed on other fishes at dawn and dusk and withdrew to rest in deep, sheltered areas during the day.

But during a summer survey, the team recorded some unusual activity. The tigerfish swam out to open water in the mid-morning and were seen preying on swallows as they skimmed over the lake's surface.

Prof Smit said the team were "extremely surprised" by the behaviour which they were able to capture on film.

In the past, anecdotal evidence of birds disappearing as they flew over African lakes and pools has suggested that fish could be catching them for food but nothing conclusive had been recorded.

Bass, eels, piranhas and pike have all been acknowledged as freshwater species that prey on birds floating on the surface of the water or by the water's edge, but Prof Smit says this is the first record of freshwater fish catching birds in flight.

He suggested that the findings will change how scientists think about how energy transfers in freshwater eco-systems - and may also have implications for swallow conservation in the country.

Source: African tigerfish catch swallows in flight (BBC Nature, 13 Jan 2014)

Barren future for Africa's soils

The Soil Atlas of Africa was presented to the Afican Union in Addis Ababa last week after five years of expert collaboration between the AU, the EU and the UN’s Food and Agricultural Organisation. The scientists hope that their new report and atlas on the soils of Africa will help to reconnect the continent’s people to their roots and raise awareness about the critical significance of soil to human existence and the authors suggest that the importance of soil is not widely understood.
“Part of the problem is that with an increasingly urban society, many people have lost contact with the processes that produce food. Most people expect to find goods on the shelves of supermarkets and have limited appreciation of the role played by soil.”
One of the most critical findings is that Africa’s soils are running out of vooma. Simply put, the soil is losing nutrients faster than fertilisers can be added. The authors say many of the soils of Africa are severely degraded by erosion and excessive nutrient depletion. On average, African farmers can afford to apply only 10 percent of the fertilising nutrients that farmers in the rest of the world return to the soil.
Adding to the problem is the fact that more than half of Africa’s land surface is made up of sandy soils (22 percent), shallow stony soils (17 percent) and young, weakly developed soils (11 percent). Deserts and drylands make up 60 percent of the land surface and fertile areas are under growing pressure because of the global trend to grow cash crops for export.
“Using state-of-the-art computer mapping techniques, the Soil Atlas of Africa shows the changing nature of soil across the continent. It explains the origin and functions of soil and describes the different soil types and their relevance to both local and global issues.”
Read full article here, and more background here. Photographic credit here

Secret of desert fairy circles uncovered

Gondwana Collection
April 29th, 2013
The bare circles in the grassy plains on the eastern fringe of the Namib have been a mystery for decades. Now it is clear what causes them: The ‘fairy circles’ are created by termites as part of a water storage system according to the findings of a long-term study conducted by German biologist Professor Norbert Jürgens and published in the latest edition of Science magazine.
According to the study the ‘sand termite’ Psammotermes allocerus clears the sandy soil of annual grasses so that rain water seeping into the ground is stored instead of being used by the grass. In areas with an average annual rainfall of 100 mm the sandy soil underneath the bare circles always holds more than five percent of water by volume – even after years of draught. Professor Jürgens obtained his data by taking readings in fairy circles found on the grounds of Namib Desert Lodge south of Solitaire over the course of several years. The lodge is part of the Gondwana Collection Namibia, which has supported the professor’s research projects for years.
The water storage system keeps relative humidity at 98 percent in the tunnels of the termites’ nest. This is essential for the survival of the insects. The storage system furthermore allows perennial grasses to take root around the circles. These grasses in turn are a secure food source for the termites in years of drought when annual grasses no longer grow because of lack of rain.
Psammotermes allocerus lives completely underground. Since it is active at night and early in the morning this termite is rather inconspicuous. This may explain why researchers did not solve the riddle of the fairy circles much earlier. Possible reasons that have been offered included theories of the ground being poisoned by Euphorbia and of natural gasses with the effect of herbicides. The circles even fuelled fantasies of little green creatures from outer space and dancing fairies from the realms of fairy tales.
The idea of termites causing the circles is not new, but so far the type of termite had not been identified and the presence of termites in the circles had not yet been proven. What is new and totally fascinating is above all the realisation that tiny, insignificant creatures are able to create an artificial eco-system and thus conquer a habitat which otherwise would be fatal for them.
Source: travelnewsnamibia.com
Information: Gondwana Collection
Photograph: Daily Mail

Dung Beetle Directions

Under stary skies...
New research in South Africa has indicated that dung beetles use the light from the Milky Way to orientate themselves when collecting dung. It has previously been established that dung beetles use polarised light from the sun and moon to orientate themselves on the ground and in flight, but researchers were intrigued as to how the insects managed to navigate on moonless nights.
Dung beetles are highly competitive when it comes to dung which, as their name suggests, is a major feature in dung beetles lives. Only about 10% of dung beetle species are 'rollers' - the rest are burrowers, or 'tunnellers', who live underground, or even 'dwellers' who spend their live, literally, in the shit. It is usually the males which collect ball shaped amounts of dung which they quickly roll off to a secure location. Dung balls are used as a food source for adults and young.
Fresh dung is usually found in random, but concentrated, amounts, and can attract a lot of attention from other dung beetles of the same, or other, species, all wanting a piece of the action. For a male with a suitable ball of dung, it is imperative he exits the stage with his prize as soon as possible, before other males attempt to steal his carefully selected and crafted dung ball. To maximise their chances, males retreat in a straight line away from the centre of attention - no easy task when pushing a ball of dung as big as yourself - backwards.
Using the African dung beetle, Scarabaeus satyrus, (one of an estimated 6,000 species of dung beetle in the world, 2,000 in Africa and 800 in south Africa), researchers found that rather than using specific individual stars for orientation, the beetles used the wider Milky Way as a reference to navigate their way around.
The study by Dr Marie Dacke of Lund University in Sweden is published in the journal Current Biology and used field experiments and even tests with beetles in Johannesburg planetarium. In the controlled tests the beetles performed equally well under a fully starlit sky and one showing only the Milky Way. When researchers strapped visors to the beetles to block out the sky entirely, they were completely disoriented.
"Dung beetles are known to use celestial compass cues such as the sun, the moon, and the pattern of polarized light formed around these light sources to roll their balls of dung along straight paths," Dr Dacke said. "Celestial compass cues dominate straight-line orientation in dung beetles so strongly that, to our knowledge, this is the only animal with a visual compass system that ignores the extra orientation precision that landmarks can offer... The dung beetles are not necessarily rolling with the Milky Way or 90 degrees to it; they can go at any angle to this band of light in the sky. They use it as a reference." Indeed, in the field, the researchers found the beetles run in to trouble when the Milky Way briefly lies flat on the horizon at particular times of the year.
Whilst celestial navigation has been shown in birds and some mammals, these are thought to be the first insects to be found to use these techniques; "This finding represents the first convincing demonstration for the use of the starry sky for orientation in insects and provides the first documented use of the Milky Way for orientation in the animal kingdom."
Previously it was assumed that insects could not use the stars because their compound eyes did not have the resolution to see points of light, but navigating using the plain of the Milky Way does away with the need to see individual stars. The question is how many other animals might use similar night-time navigation. The Lund researcher is sure there will be more discoveries to come. "I think night-flying moths and night-flying locusts could benefit from using a star compass similar to the one that the dung beetles are using," she said.
For more on Dr Dacke's research see here.
Article reference and abstract can see seen here.
[Image Credit: Current Biology, Dacke et al.)]