Read more
Geo News

Mud flood

What’s it like to be a cockle or a pipi when the sea turns to chocolate milk? Juveniles suffocate in even a thin layer of sediment, says Simon Thrush, head of the University of Auckland’s Institute of Marine Science. Adults “hold their breath” for a couple of days, then have to resume feeding—in water so full of sediment and pollutants it often kills them. In thicker layers of mud, like here at Sandspit after January’s floods, even worms “just get stuck and die. It’s gruesome.” New regulations introduced by Auckland Council in 2019 aimed to limit sediment from land development over the 12,000 building sites active each year. Last year, officers cited more than 82 per cent compliance—yet this summer of extreme rain events has defied all attempts to mitigate the runoff.
Read more
Geo News

Sunfish have pretty sweet moves, actually

To an orca, a sunfish is a bit like a watermelon: a nutritious, watery snack, but hard to swallow whole. Also like watermelons, sunfish (also called mola) don’t bite back. This makes them the ideal “training prey” for juvenile orcas, according to New Zealand orca scientist Ingrid Visser. In the first-ever review of orca-sunfish interactions, Visser, along with sunfish researcher Marianne Nyegaard and orca researcher London Fletcher, found several instances of juvenile-parent orca pairs hunting sunfish. About 40 per cent of the dozens of photos, videos and oral accounts they analysed didn’t appear to be about predation, but simply entertainment. Orcas flung sunfish like frisbees, pushed them around underwater, and balanced them on noses in what Visser calls a “mola moustache”. The researchers also found records of orcas extracting a meal of intestinal spaghetti: “It’s like they’ve got a string of sausages in their mouth, pulling them out of the sunfish, which is often still alive and swimming around,” says Visser. “They split the sunfish up like a taco or a pita bread… stick their faces in, and eat the insides out.” One underwater video filmed in New Zealand reveals that sunfish are quick on their fins despite their dinnerplate anatomy. “We thought the orca were pushing the sunfish upside down,” says Nyegaard, “but the mola was thrashing and spinning in crazy manoeuvres all by itself. I thought, ‘What the hell is it doing?!’” The sunfish was attempting to evade the orca by using a suite of sneaky moves, including spinning rapidly, breaching, flipping upside down, or positioning itself with its rigid backside towards the orca’s mouth. “People thought sunfish were just great big blobs and that mola design was cumbersome, but this adds further proof that they’re actually quite good at swimming,” says Visser. “They can breach, their cruise and boost speeds are impressive, and this is more recognition of their agility.”
Read more
Geo News

Kiekie, ambrosia of the bush

Kiekie belongs to the widely dispersed pandanus family, well known as a source of weaving material throughout the Pacific. It’s the only member of the family native to Aotearoa, and it’s best known for its deep green, glossy leaves—but it also produces fruit regarded by many as the finest delicacy of our native bush. The taste sensation of its fruit sent early settlers grasping for superlatives; they made comparisons to pineapple; ripe pears with an aroma resembling vanilla; and soft, waxy bananas. On the female plant, the fruit ripens in late autumn or early winter. Stalks produce three to five fruit (ureure) that look like a cross between sweetcorn and pineapple. The rough skin is peeled away to reveal a sweet pulp of berries inside. The male flower produces a creamy, beige stamen mounted on a sweet, fleshy base of leaves (bracts) known as tāwhara. It flowers for about a fortnight in October. Traditionally, the bracts were eaten fresh off the plant; it was always a race to beat bush rats (and, more recently, possums) to this seasonal treat. Some settlers described a cooling jelly drink made from the juice of tāwhara; others made a jelly from the flowers that apparently tasted like preserved strawberries. Kiekie is common in the undergrowth of lowland forest, its aerial roots locking into bark and rock crevices for grip as it climbs up into the canopy. Its elastic roots were collected and used extensively as lashings and for making sails on canoes. It was also used to bind together tāruke (crayfish pots) and hīnaki (eel pots). For Māori weavers, kiekie was second in importance only to harakeke (flax). Its leaves are narrower and shorter, but may be more durable under water. Strips are split from kiekie leaves, scraped, boiled, rinsed and dried in the sun to bleach. The fibre was often used for the finest whāriki (mats) and kete whakairo (woven bags) and to create tukutuku (wall panels). It was also used for rain-capes, belts and hats. In Traditional Lifeways of the Southern Maori, Herries Beattie recorded a story of the mythological origins of kiekie in Te Waipounamu. Legend has it that a character by the name of Tamatakuariki travelled down the Poutini coast in search of his wife and, in his haste, shreds of his pōkeka (rain cape) were torn off by the vegetation. These fell to the ground and germinated as kiekie. One name of the plant is therefore Te Pōkeka-a-Tama, Tama’s raincoat.
Read more
Geo News

We’re going to need a bigger evacuation zone

Pyroclastic surges—super-heated and fast-flowing clouds of gas and rock fragments—represent the deadliest risk from Auckland’s volcanic field. Previous hazard assessments assumed such surges would travel up to six kilometres, but a new study of the Ubehebe crater in California’s Death Valley shows they extend much further, and future assessments should consider distances of 10–15 kilometres from the vent. University of Otago volcanologist James White says Ubehebe’s eruption was similar to those of some of Auckland’s volcanoes where magma and water mixed to trigger more violent explosions, known as phreatomagmatic. But the Death Valley’s dry environment preserved the pyroclastic deposits exceptionally well, tracing them to at least nine kilometres. Pyroclastic surges are lubricated by a low-friction air cushion which allows them to move across any terrain. White says the somewhat cooler—albeit still lethally hot—surges from magma-water eruptions can travel even greater distances. “What hazard managers are going to be worried about is not distance but area—extending the diameter even by two or three kilometres adds a lot of area.”
Read more
Geo News

Battle of the mutants

It’s harder than you’d think for a new COVID-19 variant to take off in New Zealand, says Jo Chapman, a senior scientist at the Institute of Environmental Science and Research wastewater testing program. “Variants have to be both fit and good at growing, but also lucky—to find a pathway through the community and get a foothold.” Still, enough of them have made it through that we now have a “variant soup”. Initially wastewater testing was an early warning system—it told us where COVID-19 was stealthily spreading. Now, it’s an unbiased way of monitoring trends. The new ESR website poops.nz lets laypeople take a nosy at the data too, even zooming down to the level of a single street or two. Yes, you can now see what’s in your neighbourhood poo.
Read more
Geo News

Wavering heights

Your favourite summer surf break may fizzle out by the end of the century as a result of climate change, according to new modelling led by University of Auckland scientist João Albuquerque. Shifting wind patterns will drive slightly bigger west coast waves, while east coast breakers are set to diminish by up to 20 per cent. Seasonal patterns will fluctuate too, with summer and autumn swells smaller than today’s, while winter and spring will see them ramp up. But it’s not just surf forecasts that will flip-flop: wave directions will shift, too. These altered angles of inundation will impact coastal communities, eroding and flooding different parts of the coast. The projected changes remain subtle up to 2045, but are expected to become “more severe” between 2080 and 2100, Albuquerque says.
Read more
Geo News

Riders on the storm

In February 2022, Tropical Cyclone Dovi brought weather chaos to New Zealand’s North Island—along with a few unexpected visitors from warmer waters in the South Pacific. Noddys, frigatebirds and a bridled tern were reported from Northland, while a lone tern caught the eye of Hayden Pye, a Massey University doctoral student visiting the Muriwai colony. Colin Miskelly, curator of vertebrates at Te Papa, describes this find as “the pick of the bunch” from the flurry of vagrant sightings. It was New Zealand’s first-ever record of a black-naped tern, usually found frequenting the ocean around New Caledonia. Sadly, the emaciated tern died, but its legacy lives on as a specimen at Auckland Museum, and as a new bird on New Zealand’s official species list.
Read more
Geo News

Tying the forest together

This is one plant you won’t find in a glossy coffee-table book on the 100 prettiest native species for the garden. Supplejack is a climber that inhabits the deep, dark, shadowy gullies of our native bush. In Māori legend, supplejack is said to have sprouted from the bloody tip of the tail of the taniwha Tunaroa, whom Māui hacked to pieces and tossed far and wide into the bush for molesting his wife Raukura. Supplejack vines grow from a bulb the size of a man’s fist, their long glossy black strands about the thickness of a finger, with a knuckle at each node like bamboo. The vine wraps itself around the limbs of saplings and forest giants alike, sometimes even dragging them to the forest floor. Like many aka (vines), supplejack is regarded as a nuisance: an impenetrable tangle that strangles the life out of regenerating bush and stops trampers in their tracks. Little wonder it was known as “taihoa” or “wait-a-while” by Pākehā bushmen. But supplejack had an extraordinary range of uses. The vine’s leaves, young shoots and roots were made into medicinal tonics to treat everything from sore throats to chronic rheumatism, recorded Murdoch Riley in Māori Healing and Herbal. Pākehā and Māori used supplejack laced between a couple of saplings to make a stretcher to carry the wounded out of the bush, or to create a bed sprung with a latticework of vines. A bundle of tightly bound vines made a good torch. Set alight, the vines could also be used to cauterise wounds. Cut into slivers and boiled to extract the juice, the vines could produce a “wonderful beer; clear, gold and heady”, according to Riley. Boys built bows from supplejack. Schoolmasters used supplejack canes to discipline lads who misbehaved. In 1906, ethnographer Elsdon Best noted hoops of supplejack poked into the ground and lashed together to support the weight of a young child learning to walk. Supplejack was used to make all sorts of ingenious fishing devices, traps, nets and scoops. Stiff, springy hoops of vine were used to hold open the mouths of scoop nets or to strengthen and reinforce fish traps, hīnaki (eel nets) and bag nets. Many Ngāi Tahu whānau still remember cutting supplejack vines from the bush and building tāruke (crayfish pots) in the mid-1900s. In latter years, the designers improvised with hybrid designs, lacing supplejack hoops together with No. 8 wire. They weighted their pots with concrete or scrap iron donated by New Zealand Railways. Tāruke had significant advantages over the steel-framed, wire-netting-clad pots that eventually replaced them; they didn’t rust and were durable and flexible enough to withstand perhaps a decade of the worst storms Tangaroa could throw at them. Excerpted from Treasures of Tāne: Plants of Ngāi Tahu by Rob Tipa (Huia Press).
Read more
Geo News

Step away from the kākāpō

The 2019 kākāpō breeding season was the best in the 26-year history of the recovery programme. But it was also the worst: the fungal disease aspergillosis hit the Codfish Island/Whenua Hou sanctuary, infecting 21 kākāpō and killing nine—all either nesting females, chicks or juveniles. New fungal genome analysis shows the birds all caught the same strain—and it probably came in with people, most likely on supplementary food. That is surprising, says University of Otago geneticist Peter Dearden, but “we can’t explain it unless it’s been carried by humans”. The same strain of aspergillosis was also identified on Anchor Island in Fiordland, home to a smaller kākāpō breeding population. But the birds there didn’t get sick. [caption id="attachment_472574" align="alignnone" width="600"] Kākāpō Huhū’s results show the shadow of the fungus, though the bird survived.[/caption] Other factors such as climate change are likely in play. “It was a very hot, dry summer in 2019,” says Andrew Digby, the science adviser for DOC’s recovery programme, who was involved in the research. “All the infections occurred over quite a narrow time period, and it might be that the climatic conditions were [right on Whenua Hou] at the same time as chicks were at their most vulnerable stage.” All islands where kākāpō breed are subject to strict quarantine and hygiene procedures, but the team have now put in additional measures such as freezing supplementary food, ventilating nests and not moving chicks directly between them. They rely more on remote monitoring and have established hands-off breeding sites on Te Kākahu-o-Tamatea/Chalky Island in Fiordland. “That’s how we want to be managing kākāpō in the future,” Digby says. “It’s not to say the intense management is wrong. Without it, kākāpō would be virtually extinct by now. But it’s another reason why it’s important that we step back.”
Read more
Geo News

Teaching drones to soar like birds

Flying robots are taking to the skies in greater numbers—performing tasks such as tracking critically endangered Māui dolphins and collecting data on extreme weather events. But they can’t fly well in windy conditions, and don’t have the battery capacity to power long flights. Birds, on the other hand, can wheel and soar in even the most turbulent conditions, exploiting wind energy to fly effortlessly. In a new paper, birds provide inspiration to make drones more adaptable and energy efficient. Researchers suggest mimicking flying strategies such as vultures circling in thermal updrafts (below, D, E), or birds exploiting updrafts created by the likes of cliffs or buildings (F). “Dynamic soaring” strategies seen in gulls, kites and crows could inspire drones programmed to be more reactive to subtler air patterns. These include surfing wind gusts (above, A), sweeping close to the sea surface on the updraft of a long wave (B), or looping in the eddies off the tip of a sharp ridge (C).

Read more
Geo News

State of cray

The crayfish population in the Hauraki Gulf is in worse shape than official fishery stock assessments suggest, according to a new analysis. Researchers from the University of Auckland used two marine reserves— Cape Rodney-Okakari Point (Goat Island) and Tāwharanui—as “proxies” for natural, unfished crayfish abundance. “We hired a fisherman and all of his gear and we did cray potting inside and outside the marine reserve for two years,” says Benn Hanns, lead author of the paper. Comparing catch rates inside and outside the marine reserves indicates that the crayfish population has plummeted to around two to three per cent of unfished levels—though Hanns suggests the population may be even lower. It’s substantially different from the Ministry for Primary Industries’ estimate of 18 per cent. Under current rules, if a fishery drops below 10 per cent of its original, unfished level, it must be closed. Stock assessments rely heavily on fisheries-dependent data and models with complex, inbuilt assumptions. Hanns says some of these assumptions are outdated. “This research shows the utility of marine reserves beyond conservation… They can actually be these really important sanity-checking tools.” But even within the marine reserves, numbers of crayfish have been declining in recent years. Hanns chalks this up to one big problem: the marine reserves are too small. His research has contributed to a recent proposal to expand Goat Island Marine Reserve, currently under consideration.
Read more
Geo News

Minister’s decision found “unlawful”

The NGO Environmental Law Initiative (ELI) took the Minister for Oceans and Fisheries to the High Court in October, challenging the decision on the total allowable catch of crayfish in Northland. (As part of a no-holds-barred commitment to oceans journalism, New Zealand Geographic was involved in preparing and presenting the case.) ELI contended that the advice to the minister was “inaccurate, misleading, and unsupported by peer-reviewed and published literature”, and that the minister had failed to consider the “interdependence of species” in the marine environment that ultimately leads to trophic collapse—the kina barrens that New Zealand Geographic reported on in November 2021. The court found that the fisheries decisions were “unlawful” and ordered Minister David Parker to remake the decision based on best-available information, considering the wider impacts of rock-lobster fishing and taking a precautionary approach. This sets a precedent for other decisions and may accelerate an ecosystem-based approach to fisheries management that has long been proposed by those concerned about environmental impacts of human activity in the seas.
Read more
Geo News

Was Haast’s eagle bald?

New Zealand’s extinct Haast’s eagle may have hunted like an eagle, but it feasted on guts and organs like a vulture, according to new research. The giant bird of prey’s beak and talons closely resemble those of living eagles, while its skull is more alike to the Andean condor, a type of vulture. This finding suggests that Haast’s eagle may have had the featherless head typical of vultures—which aligns with a Māori rock painting of an eagle with a black body but an uncoloured head and neck.
Read more
Geo News

Colourful catch-22

Nearly 500 songbird species have been flagged as targets for wildlife poachers thanks to their unique plumage. Among them are three New Zealand species: the popokōtea/whitehead, mohua/yellowhead, and kōkako. Like their parrot cousins, songbirds garbed in eye-catching colour palettes attract more human admiration. But bright colouration is a double-edged sword: it also makes birds highly sought after in the pet trade. In turn, this means that populations dwindle as poachers snaffle birds from the wild—a fate that currently befalls around 30 per cent of songbirds, especially in the tropics. Colourful birds in the “perching bird” (passerine) family are more likely to be both traded and threatened with extinction, according to a new analysis. Surprisingly, white is a popular hue in captive birds—exemplified by the Bali myna, which tops off its snowy plumage with a crisp black tail-tip and zingy blue eye-liner. The myna is critically endangered due to poaching for the caged-bird market. As populations of desired species decline, poachers shift their efforts to birds with similar qualities. “Most of New Zealand’s birds are not too colourful—although the hihi and kōtare offer obvious exceptions,” says study co-author James Dale from Massey University. Nonetheless, New Zealand is pinpointed as a place that could see a drop in both colour diversity and uniqueness among birds. Without conservation efforts and proactive trading regulations, the future for our feathered friends could be decidedly drab.
Read more
Geo News

Green light for comets

As comets streak across the night sky, their radiant heads often glow green—but not their long tails. In the 1930s, physicist Gerhard Herzberg suggested that the lime halo may be produced by sunlight destroying diatomic carbon, C2. But because diatomic carbon is so unstable, no one on Earth has been able to test that theory—until now. Researchers in Australia used a vacuum chamber and powerful lasers to simulate the comet environment, proving that the breakdown of C2 produces the emerald hue.
Read more
Geo News

Superhero snaps

A pivotal scene in the superhero movie Avengers: Infinity War involves one character snapping his fingers while wearing a metal gauntlet. It made biophysicist Saad Bhamla wonder: would it actually be possible to snap your fingers while wearing such a glove? Turns out, no one had explored the physics of the finger snap, so Bhamla and his colleagues at Georgia Tech in the United States filmed a finger snap in ultra-slow motion. The key to a successful finger snap is skin friction, which is partly created by the squishiness of the finger pads. Skin friction builds up energy like a compressed spring, then releases it quickly to fuel rapid motion. During a finger snap, the middle finger rotates about 20 times faster than the blink of a human eye, and when it hits the palm, the impact creates a mini-shockwave, producing that characteristic pop. Researchers failed to snap while wearing slippery gloves or stiff metal thimbles, while bare skin created the perfect amount of friction. The verdict: Thanos’s snap wasn’t possible according to actual physics, but researchers admitted they could not account for the supernatural powers of the gauntlet.
Read more
Geo News

Plastic Archaeology

If you sail west from California for nearly a week you’ll end up in the Great Pacific Garbage Patch. Then the plastic starts bobbing past—a buoy, a bucket, a net, a toothbrush, microplastics floating like bubbles—tens of thousands of tonnes of it spread over an estimated 1.6 million square kilometres.
Read more
Geo News

Mussel building

One day in 2008, marine science student Kura Paul-Burke was diving in Ōhiwa’s murky waters when the grey-brown of the sea floor suddenly gave way to a brilliant orange. At first, she was struck by the beauty of it. Then she realised she was looking at hundreds of thousands of 11-armed sea stars—pātangaroa, a native species—stacked five or six layers deep. Behind them, the seabed was littered with empty green-lipped mussel shells. In 2007, the Bay of Plenty harbour was home to an estimated 112 million mussels. By 2019, only 78,000 were left. Paul-Burke’s Ngāti Awa elders had noticed signs of decline well before then. No-one knew why the mussels were dying. Was it overharvesting? Sedimentation? But they knew there used to be more mussel beds, and in 2006, they urged her to investigate—then helped her to map the old mussel beds using both traditional landmarks and scuba surveys. Researchers are still confirming the starfish are to blame, and figuring out what is causing the ecosystem imbalance in the harbour. In the meantime, Paul-Burke—now a professor of mātai moana (marine research) at the University of Waikato—wanted to see if it was possible to save the mussels and the harbour. The project wove together four iwi (Ngāti Awa, Te Ūpokorehe, Te Whakatōhea and Waimana Kaakū [Tūhoe]) and three councils, kaumātua and young people (pictured below, L-R: Megan Ranapia, Te Waikamihi Lambert and Cameron Phillips), mātauranga Māori and marine science. Together, they built four restoration stations where baby mussel spat could attach and grow. Instead of using commercial plastic spat lines, they experimented with natural fibres. The strongest were made from fallen tī kōuka leaves woven into rope by master weaver Rokahurihia Ngarimu-Cameron and her students. In late 2018, the team hung them on floats in midwater, out of the reach of clambering starfish. It worked. Mussels began growing in such numbers that they dragged the floats under the surface. When the tī kōuka lines eventually degraded, young mussels fell to the bottom “as a whānau”, Paul-Burke says, before reattaching to the sea floor. As the researchers describe in a new paper, by 2021, three new mussel beds had formed close to the restoration stations, and the mussel population had increased ten-fold—showing what can be accomplished, says Paul-Burke, when several knowledge streams and communities pull together.

Read more
Geo News

Clicky cliques

Sperm whales are tribal creatures—and they avoid interacting with those from other clans, even when they share the same waters. But how do they identify each other?
Read more
Geo News

End of the red-and-golden weather

In New Zealand, if you see a tree turning red or golden in autumn, it’s almost certainly exotic. Out of more than 500 native species of woody flowering plants, just 10 lose their leaves in winter—most notably the tree fuchsia, kōtukutuku. But northern hemisphere forests at similar latitudes are full of deciduous trees, and in South America, close relatives of our southern beech trees drop their leaves each year. So why do Aotearoa’s temperate forests stay green, and was it always this way? Geologists examined a hundred fossil leaves from four sites in Otago dating back to the middle Miocene—around 11-16 million years ago—and found multiple lines of evidence that some of our extinct beech species were deciduous. The leaves of several deciduous Chilean beech species appear corrugated, with deeply etched veins, and the scientists found the same patterns in some of the Otago fossils. The leaves were also large, comparatively light for their size, and poorly defended, as evidenced by insect attacks—all trademarks of deciduous trees. (If you’re going to keep your leaves for just six months, it makes sense to make them cheap and disposable.) But here’s the paradox. Otago in the Miocene was much, much warmer than it is today. There were crocodiles and palm trees. If the winters weren’t frigid, why were those ancient beeches shrugging off their leaves every autumn? Lead author Tammo Reichgelt from the University of Connecticut theorises that deciduousness is less about temperature than light. Central Chilean summers are practically cloudless, while westerly winds make winters cloudy and wet. In New Zealand, cloud cover is relatively constant through the year. In Miocene Otago, as in Chile, the beeches soaked up the abundant summer sunshine—“it was really worth it to photosynthesise a lot”, says Reichgelt—but there was little point to keeping green during the dark, wet winter. Then, at the end of the Miocene, the planet cooled dramatically. Zealandia got wetter, its seasons less pronounced. “It wasn’t worth it anymore to throw away your carbon in autumn,” says Reichgelt—so all our deciduous beeches disappeared.

Loading..

3 FREE ARTICLES LEFT

Subscribe for $1  | 

3 FREE ARTICLES LEFT THIS MONTH

Keep reading for just $1

$1 trial for two weeks, thereafter $8.50 every two months, cancel any time

Already a subscriber?

Signed in as . Sign out

SEE THE OPTIONS

{{ contentNotIncluded('company') }} has not subscribed to {{ contentNotIncluded('contentType') }}.

Ask your librarian to subscribe to this service next year. Alternatively, use a home network and buy a digital subscription—just $1/week...

Go back

×

Subscribe to our free newsletter for news and prizes