Two New Zealanders have devised an ultra run on the border of Southland and Otago that they claim is too hard for anyone to finish. In January, people from around the world lined up to prove them wrong.
Forest soils take a long time to recover from disturbances such as bushfires or logging. Soils lose nutrients when heated—fires can result in soil temperatures of more than 500°C—while logging alters the soil structure, exposing and compacting various layers. When researchers from the Australian National University collected 729 soil cores from 81 sites in the mountain ash forests of Victoria, they found it took soils up to 80 years to recover to their former nutrient density and quality following a bushfire, and 30 years following logging.
On spring nights, bogong moths migrate to the Australian Alps, travelling distances of more than 1000 kilometres to reach the cool mountain caves where they spend their summers aestivating. But how does the moth navigate from its winter breeding grounds to the alps? Tests in a flight simulator found moths found their way by the stars and moon, but became disoriented when researchers deliberately misaligned the sky and the Earth’s magnetic field. That magnetic field is crucial to the moths’ ability to find their way, making bogong moths the first nocturnal insect known to use magnetic sensitivity as a tool in long-distance migration. (Birds have long been known to navigate using the Earth’s magnetic field.) Do other insects have an internal compass tuned to the Earth’s magnetic field? Study co-author Eric Warrant, a sensory physiologist from Lund University in Sweden, says monarch butterflies, which migrate by day across the United States to overwinter in Mexico, may also have some magnetic sensitivity, but their primary compass is the sun: “Bogong moths must rely on the Earth’s magnetic field because the moon is a very variable and unreliable cue compared to the sun—which is a very constant cue day after day.”
On January 29, the Nelson Mail published a prophetic story: the fire risk in the region was the highest since 2001, a year of record drought. A week later, a contractor ploughing a paddock sparked a blaze that quickly covered 2000 hectares and threatened homes. “The start to summer was the third warmest on record for New Zealand,” says NIWA meteorologist Ben Noll. “The warm pattern has been a result of very warm sea-surface temperatures, both in New Zealand coastal waters and in the Tasman Sea, as well as a lack of cool southerly winds.” January 2019 is now the sunniest month on record for the entire South Island. Tasman experienced a 22-day dry spell—defined as consecutive days with less than 0.1 millimetre of rain—while Nelson has recorded 84 millimetres of rain during its summer, which would normally see 224 millimetres. Regional fire officers in the region report the highest fire-danger levels they’ve seen in 20 years. Scion’s fire buildup index, which reflects the amount and dryness of fuel, is more than twice as high as the historical average. In an average year, Nelson would have nine to 10 days of very high or extreme fire danger, says Grant Pearce, a fire scientist at Scion’s Rural Fire Research Group, but modelling shows that is likely to increase to 12-13 days on average, and 20-25 days in the worst years. It’s not the only region to experience change: “The number of severe fire-weather days is likely to increase in many parts of the country.”
Birds with colourful plumage are better at attracting mates, but also more likely to attract predators—right? Well, no. When a team of New Zealand and Australian biologists investigated whether dull-coloured birds had better survival rates than brightly coloured ones, they found both were equally likely to be attacked. The fairy-wren, an Australian songbird, varies wildly in colour—some have brilliant plumage, while others are nondescript. The researchers placed 3D-printed models of the birds at eight fairy-wren sites in Australia, then settled in to watch. They found that 13.1 per cent of brightly coloured female birds were attacked, compared to 13.6 per cent of dull-coloured females. But there was a wide discrepancy in the rate of attacks between sites, suggesting that survival had more to do with vegetation and location than the flashiness of the birds’ feathers. “While being brightly coloured can be important, for example in competing for a mate, the assumption has been that it is costly for birds because it appears to scream ‘Here I am, come eat me’,” says lead researcher Kristal Cain of the University of Auckland. “It suggests the relationship between predation and colour is not as simple as we might have thought. “Instead, it appears that because males and females behave differently—females often take more risks—bright feathers may be more dangerous for females than for males.”
Death was once a constant presence. People passed away at home, and their bodies remained there until burial. Art was full of reminders of our own mortality, while churchgoers confronted the afterlife every Sunday morning. Today, death has been abstracted—it takes place in hospitals, the deceased are swiftly removed to funeral homes, and we no longer decorate our homes with reminders that, one day, our time will be up. What have we lost?
Birds fly at high speed through dense forests without crashing into trees or leaves—and this navigational prowess may be due to their ability to see ultraviolet light. Two researchers photographed forest habitats with a multispectral camera, allowing them to look at the scenes through the birds’ eyes. In a paper published in Nature Communications in January, they determined that contrast between leaf surfaces was greater with UV vision, and speculated that UV vision also helps birds search for particular leaf surfaces, leading them to prey or safe refuge.
Birds may have lost their teeth to speed up hatching time, according to a new theory published in May in Biology Letters. The toothless beak is a relatively recent invention. Dinosaur birds had teeth, and incubated their eggs for a lengthy three to six months. Research on fossil embryos shows tooth formation took 60 per cent of this time. But eggs in open nests are vulnerable to predation, compared with mammal embryos that are protected inside the womb, or eggs that are buried. Losing teeth would allow for a shorter incubation time—and thus a higher survival rate for chicks. Other theories postulate that birds lost their teeth in order to become light enough to fly, and that the toothless beak is better adapted to certain foods.
Beneath the waters of Lake Waikaremōana is a lost world, a 2000-year-old tableau of the lake's surprising origin.
Some blind people are able to detect and respond to visual cues that they cannot see. The mechanism for this ‘blindsight’ was previously unknown, but researchers at the University of Queensland’s Brain Institute now believe they have identified the cause. If a person’s primary visual cortex is damaged—usually through a stroke or injury—the brain isn’t able to receive and process visual input from the eyes. Brain researcher Marta Garrido proposed the existence of a ‘shortcut’, another pathway in the brain. In a study published in January in eLife, Garrido identifies a connection between the retina and the centre of the brain, bypassing the primary visual cortex. The discovery, she says, raises questions of why the brain evolved alternate but parallel pathways. “One possibility, I think, is redundancy—so if one thing fails, then we still have the ability to process things that are really, really important, like danger and navigation. “You ask someone with blindsight how they know where to navigate to, and they will tell you, ‘I don’t know, I just had a feeling’. And understanding where that feeling comes from is fascinating.”
Takahē numbers are rising by 10 per cent a year. The problem now is where to put them.
The more species a subtropical forest has, the better at storing carbon it is. A study of forests in China, published in Proceedings of the Royal Society B, found forests that were more species-rich cycled carbon faster and stored more carbon in trees, roots, litter, deadwood and soil. For every additional tree species, the total carbon stock increased by 6.4 per cent—suggesting that planting a mixture of trees rather than a monoculture creates more effective carbon sinks.
British artists Ruth Jarman and Joe Gerhardt turn data into art. One of the pieces at the duo’s upcoming solo show at City Gallery, Wellington, compiles seismic data from around the world—including the Kaikōura earthquake of 2014—into a dynamic moving picture that condenses eons of tectonic change into minutes. This piece, Earthworks, along with others, will be on display from March 23-July 14.
The first global review of studies about the decline of insects predicts the planet will lose its insects within a century if the current rates of extinction continue. Notable insect population crashes have been documented in Puerto Rico, where one study found a 98 per cent decrease in ground insects over 35 years, and the United Kingdom, where butterfly species dropped by 58 per cent in a decade on agricultural land. In Oklahoma, only half of bee species recorded in 1949 were found in 2013, while in Germany, the abundance of flying insects in national parks declined by 75 per cent over 25 years. Insects are the most abundant animals on Earth—they outweigh humans by 17 times—but their mass has been declining by 2.5 per cent a year for the past three decades. The insect rate of extinction is eight times higher than that of birds, mammals and reptiles. According to the analysis, which will be published in Biological Conservation in April, the decline in insect numbers is primarily due to intensive agriculture, heavy pesticide use, loss of habitat through urbanisation and climate change. “Unless we change our ways of producing food, insects as a whole will go down the path of extinction in a few decades,” write the authors of the review. “The repercussions this will have for the planet’s ecosystems are catastrophic, to say the least.”
A happy hihi, or stitchbird, has a call that sounds like two marbles clacking together. Using sound-recording devices, researchers listened to hihi calls in Rotokare Scenic Reserve in Taranaki to determine whether the reintroduction of the birds to the area was successful. “By recording and listening to the hihi calls, we were able to figure out how the birds were using the area they’d been reintroduced to,” says PhD candidate Oliver Metcalf, from a Zoological Society of London research team. “Using the calls, we found the birds moved from an initial exploration phase around the habitat, to a settlement phase—meaning the birds had established their own territories.” It’s hoped that auditory monitoring may replace more-invasive radio tracking for some species. Since 2004, six new populations of hihi have been established across their former range.
The science of human endurance is fascinating because it is so little understood, so variable, and because excelling at a monumental task isn’t simply a matter of physical strength. “If races were really just plumbing contests—tests of whose pipes could deliver the most oxygen and pump the most blood—they would be boringly deterministic,” writes Alex Hutchinson in Endure: Mind, Body and the Curiously Elastic Limits of Human Performance. “You race once, and you know your limits. But that’s not how it works.” After 24 hours of physical exertion, it isn’t baseline strength that matters as much as mental fortitude, and grit is equally available to both sexes. The same weekend as the Revenant ultra run featured in this issue took place, a British woman, Jasmine Paris, won a 431-kilometre mountain race along the Pennine Way between England and Scotland. (Her time of 83 hours, 12 minutes set a new course record.) Viewing the Revenant in person involved a lot of waiting on tussock-clad hillsides, but I was enthralled, fully invested in the success or failure of 21 people I’d only just met. An ultra runner requires the qualities we most admire about the New Zealand psyche—they are proto-New Zealanders. We value effort when no one’s watching. We value persistence over talent, and across extremely long distances, sheer stubbornness—call it bloody-mindedness—is what prevails. We value toughness, the kind that can’t be built in gyms or isolated by sports scientists. We value capability and self-sufficiency. In the Revenant, runners figure out a route across trackless land, face up to the elements, judge the time from the setting of the moon or the rising of the sun. They cannot receive any help. “It comes down to the ability to keep going at any pace,” says Dave Viitakangas, who is on the cover of this issue. (He completed a full loop of the course, despite an injury.) Ultra running prompts us to ask the question: how would we fare if it was only our mental strength on the line? The pursuit of that great reckoning of psychological fortitude is what draws people in increasing numbers to marathons, to long missions in the hills. “When you are by yourself and you know that you are the only one that you can rely on, I feel like that’s when you are the sharpest as a human being,” said one of the Revenant runners, United States Navy SEAL Chadd Wright, in a Trail Runner Nation podcast after the race. “When you can’t look to someone else to have that courage in a moment of weakness and you’re by yourself and you know your only option is to rely on yourself—at times you can be sharper at that point than you would be within a group.” Wright raced in a team of two, but the pair of them experienced a moment of intense isolation. Emerging after nearly 30 hours from a psychologically difficult section of the course, his teammate wondered about contacting the race organisers to let them know where they were. The realisation dawned on Wright: “No one cares where we are.” Acknowledging it was a form of liberation: returning to home base was entirely up to him, and when he finally arrived back, the achievement would be entirely his. That’s the whole purpose of the Revenant. Here, the only race takes place within. Sure, the Revenant has its critics—too long, too hard, inspires people to do dangerous things. And why create an event where you expect everyone to lose, anyway? “If you’re going to face a real challenge, it has to be a real challenge,” said Gary Cantrell, the founder of the Barkley Marathons, a difficult ultra race in Tennessee. The Barkley has become legendary, attracting documentary crews, as well as news coverage every time it’s run, even though most years, no one finishes. Cantrell started the Barkley for one reason entirely: “You can’t accomplish anything without the possibility of failure.”
Science denial, like so much brash narcissism, may actually be a cry for help.
By the time Choie Sew Hoy arrived in Dunedin, Otago’s first gold rush was sputtering out. The supply of alluvial gold that could be extracted by pans, cradles and sluice boxes was gradually dwindling, yet large deposits remained, buried in river gravel. Sew Hoy was a merchant rather than a miner—his Dunedin store imported and exported goods to Australia, China, the United States, and Great Britain—and in the late 1880s, he persuaded other Otago investors to try a new type of gold extraction. His steam-powered bucket dredge on the Shotover River was so successful that, in 1889, it launched a second gold boom in the area. After the Shotover, Sew Hoy started looking for new claims. The Nokomai Valley in Southland was known to contain gold, but miners hadn’t been able to work there because its gravel layer was too deep. Gold extraction would require hydraulic sluicing, which used a lot of water, which the Nokomai Valley didn’t have. Sew Hoy had both patience and capital. He paid work crews to build two water races to the Nokomai Valley—one of them becoming New Zealand’s second-longest, extending 47 kilometres from Roaring Lion Creek in the Garvie mountains. It took a team of 30 men three years to cut it by hand, using picks and shovels. And it was with picks and shovels that, more than a century later, Southland farmer Tom O’Brien and a small group of volunteers cut the walking and mountain-biking track that now runs alongside it. It took them two years, working under sun, snow, hail and rain, as the first racemen did, using only materials found on the land. Blackmore Station has been in O’Brien’s family for several generations. The land straddles two regions: on one side, the tawny gold hills of Central Otago, and on the other, the green river valleys of Southland. In the centre is a schist tor, Welcome Rock. Today, the Roaring Lion Track is a 27-kilometre loop for walkers or intermediate-grade mountain bikers. Along the way are fragments of mining history, swimming holes, and, if you’re looking closely, Powelliphanta—giant carnivorous snails. The track begins near Garston, about an hour’s drive south of Queenstown, and must be booked in advance online at Welcome Rock Trails. It can be accomplished in a day, but two huts on the tops—the historic Mud Hut and newer Slate Hut—allow people to break their journey. They overlook the Nokomai Valley, where Sew Hoy’s company eventually made a fortune. Though Sew Hoy died in 1901, his gold operation continued under the direction of his son and, later, his grandson. By 1932, the Nokomai Hydraulic Sluicing Company had extracted £223,043 worth of gold.
A violin reprises the ANZAC experience of war.
Mary Oliver showed us how to look at what’s around us.
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