Swimmable rivers or more hooves on pastures—is there a way of improving water quality without paralysing the primary sector? Or has agriculture reached an environmental tipping point?
Turning over the soil to prepare it for planting is a fixture of the agricultural calendar, but it’s also devastating for earthworms. Conventional tillage uses a plough to invert the soil and bury weeds and leftover crops, but it also exposes earthworms to predators and harsh weather, compacts the soil, and destroys organic matter rather than leaving it to decompose. Afterwards, earthworm numbers take up to ten years to recover. By contrast, in land planted without tilling—usually by drilling seeds into the soil—earthworm numbers are 137 per cent higher, according to research published in Global Change Biology, which looked at 215 field studies from 40 countries, from as far back as 1950. Organic matter in the soil was also up 196 per cent. No-tillage is becoming more popular around the world, because it conserves soil structure and reduces erosion, although more herbicides are generally used to kill weeds. Anecic worms, which take food from the surface but dive deep between soil layers and set up permanent burrows, were particularly affected by conventional tillage, as were epigeic worms, which live in surface mulch. While earthworms found in cultivated land in New Zealand are non-native, these guests now have a critical ecosystem role, recycling organic matter, making nutrients more available to plants, and improving soil structure.
Tea plants make large amounts of caffeine and flavonoids compared to other varieties of camellia, and it does this it by copy-pasting particular genes like crazy. When scientists from China’s Kunming Institute of Botany sequenced the genome of tea, Camellia sinensis, they discovered it was unusually long. At 3.02 billion base pairs, it is four times the size of the coffee genome. More than half of these base pairs are ‘jumping genes’, which replicate themselves over and over again. Inside some of these repeated pieces of DNA are genes which make catechins, flavonoids and caffeine, and contribute to stress tolerance—all-important for flavour and for the adaptation of tea to plantation sites all over the world.
This issue’s cover posed a challenge: to present cannabis in a way that was recognisable, but that didn’t immediately call to mind a number of associations. An image of a cannabis leaf has layers of meaning attached to it. We wanted to make it possible for readers to take a fresh look. We are, as a nation, taking a fresh look at cannibis. Last year a survey found that nearly two-thirds of us didn’t have a problem with people using it for fun, and even more people thought it should be available for medical purposes. As with alcohol, we seem to be happy to leave the risk calculation up to the individual. (I think my dad summed up the views of those two-thirds of New Zealanders quite well: “You should be free to misuse your body however you like.”) In another survey, most people said that of all New Zealand’s environmental features, rivers and lakes were the worst-managed—and two-thirds of people believed dairy farming to be the culprit. In other words, we shouldn’t be free to misuse land however we like. We shouldn’t be allowed to spread certain substances on the nation’s pastures. Less management of cannabis, please, and more of freshwater. Our social views change slowly enough that the government ought to be able to keep up. On these issues, it hasn’t. As we begin to value things differently, the costs of them change, too. Since European settlers arrived in New Zealand, the nation’s waterways have been treated as a pre-fabricated sewage network—put it in the river, and the river carries it away. We don’t want to use our rivers in this manner anymore, but the primary sector has been caught by surprise at the change—not to mention the need to invent a brand-new nationwide nutrient-drainage system from scratch. As Kennedy Warne describes in his story on rivers, agriculture and environmental tipping points on page 36, a large group of scientists are working on this problem, but the solutions aren’t free or easy. Animal-derived foods cost more than the price we pay for them, and our waterways pay the difference. We can remove this cost from our lakes and rivers if we take it on ourselves, but the size of the issue means that it can’t be left to individual decision-making—regulation is required. Meanwhile, our other value change is looking better for the nation’s bottom line. Treasury has already done the maths on the revenue it stands to gain via GST and company taxes on legalised cannabis—and it’s in the hundreds of millions. Not to mention the potential savings to police of no longer enforcing prohibition. Costs, returns, values—it is a complex public equation, but I invite you to open this issue and make a fresh calculation with an open mind.
Researchers have already figured out how to build infrastructure on Mars, in anticipation of humans eventually colonising the red planet. Using simulated Martian dirt, they created bricks stronger than reinforced steel. The researchers, from the University of California San Diego, say Martian habitats would ideally be constructed from locally available soil, with no additives or heat treatments. So they made a Martian-soil simulant, called Mars-1a, which had high amounts of nanoparticulate iron oxides and oxyhydroxides. (These are also the compounds which give Mars its reddish colour.) When compressed at high pressure, the nanoparticulate iron oxides bonded together, resulting in extremely strong bricks.
We can’t decide what to call it—marijuana, dope, pot, grass, bud, green, hash, weed, devil’s lettuce, jazz cigarettes—or how to manage it. One thing is certain: cannabis is undergoing a radical image makeover.
Beneficial gut bacteria may be killed by global warming, according to a study conducted on British lizards by researchers at the University of Exeter and University of Toulouse—to the reptiles’ great detriment. Scientists put viviparous lizards (Zootoca vivipara) in enclosures that were two and three degrees warmer than the average temperature to simulate predicted climate change. Lizards made ideal subjects as, being cold-blooded, they are unable to internally regulate their temperature. While some types of bacteria died over time and some flourished, the overall biodiversity of the warmer lizards’ gut bacteria plummeted 34 per cent compared with the control group. Afterward, the lizards were kept in a common garden for a year, where more of the ‘warmed’ lizards died. Study author Elvire Bestion says while discussion about climate-driven biodiversity loss tends to focus on charismatic animals, there’s a risk to forgetting about what’s on the inside.
Earth’s early days remain shrouded in mystery, but Kathy Campbell is helping to clarify how life began—and whether there was life on Mars.
University of Otago professor Philip Seddon suggests a few things to consider before bringing Haast’s eagle back from the grave.
Scientists are now spying on bird colonies via satellite.
When a 400-year-old play was brought to life in Auckland with Pasifika costume, dance, language and actors, audience numbers broke records.
Mother Aubert’s homemade medicine.
In determining priorities—or simply making sense—the order matters.
An unlikely crew is given the assignment of catching birds in butterfly nets on a weather-beaten subantarctic island.
One of the most important historic buildings in the New Zealand mountains.
On Monday, February 13, an electrical fault on Early Valley Road at Lansdowne near Christchurch sparked a fire. An hour and a half later, another fire was reported several kilometres further east, near Dyers Pass, one of three roads crossing the Port Hills. By Wednesday night, the fires had joined to become one large conflagration, burning more than 2000 hectares, destroying nine homes and numerous other buildings and resulting in one death before they were finally extinguished, 66 days later. The fires started when a dry northwest wind was blowing. It wasn’t particularly strong, but the northwesterly had low humidity, typical of air that has crossed a mountain range. During its descent from the top of the Southern Alps, 3000 metres above sea level, the higher atmospheric pressure compresses the air, causing its temperature to rise. By the time it reaches Christchurch, it is often 10 degrees warmer than before it crossed the alps. Most of the water carried by the air falls as rain when it rises over the mountains, so there is very little moisture left once the air reaches sea level on the Canterbury side, where the humidity can be as low as 20 per cent. Heat radiating from the flames dries the fuel in the fire’s path, evaporating much of the water inside wood and foliage. Evaporation happens more efficiently when the surrounding air has low humidity. In addition, heat radiating from the flames travels more easily through air with low humidity—water molecules in the air intercept infrared radiation from the flames, then re-radiate that heat in all directions. Lower humidity means fewer water molecules in the air, and so infrared radiation from the flames is more directional: more of it reaches the fuel. The Port Hills fire accelerated rapidly when the wind increased on Wednesday, February 15. It was now blowing from the northeast, meaning that at first, it brought back the low-humidity air spread over the ocean by the previous day’s northwesterly. A day later, the northeasterly was blowing air that had spent a long time over the ocean. Consequently, humidity shot up to 100 per cent at the top of the Port Hills, and 90 per cent lower down, helping firefighters control the blaze. As temperatures rise around the world, wildfires are becoming larger and more frequent. The tropics are expected to warm faster than Antarctica in the decades to come. The increasing temperature difference between these two regions will strengthen westerly winds over New Zealand, raising the risk of wildfires over eastern areas of the country.
Photographing actors on the set of a Shakespeare play is a far cry from Peter Meecham’s last story for New Zealand Geographic. In 1992, he documented a 160-kilometre horseback journey through Central Otago for the magazine; 25 years later, he’s back, with the story of a four-month theatrical production in Auckland. Meecham, a photojournalist who works for a variety of newspapers, is more accustomed to spending time on the sidelines than in the wings, but the Pop-Up Globe and the passion of its cast and crew proved unexpectedly compelling. To his surprise, his 13-year-old son also took a liking to the plays, insisting on being his assistant in order to covertly watch the performances—and developing a brand-new interest in the arts. “He’s the captain of the open-weight under-13 rugby team in Auckland, he’s rugby-mad, he plays cricket, he watches basketball consistently on TV—it drives me nuts,” says Meecham. Meecham had a front-seat view of the evolution of the four plays, following them from previews through to closing nights. He saw jokes emerge and actors’ confidence grow, as the crew formed a tight-knit bond born of their marathon four months of shows. The plays may be 400 years old, but as Meecham and his son saw first-hand, they can still make an audience of a thousand people laugh.
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