In our rush to plant more trees, are we creating an environmental nightmare?
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In our rush to plant more trees, are we creating an environmental nightmare?
Read about birds, make some bird paintings with your hands!
Ten New Zealand climate stations have operated from the same locations since at least the 1940s. The charts shown present data collected from these sites to address a simple question: Which years were warmer and cooler than the station’s average temperature? The results are stark. Over the past 80 years, these places have recorded a warming trend close to 1°C. Aotearoa is getting hotter. NIWA scientists forecast these trends will continue. Likely impacts include more intense winter rainfalls, drier summers and sea-level rise. How to read Charts show annual average temperature anomalies. Station averages are calculated from the 1961-90 climatalogical period. Positive bars represent warmer years than normal. Negative bars show cooler years. Gaps in a chart denote years with incomplete climate records.
New Zealand’s second-biggest climate challenge is how we get around. This is what we could do about it.
Legend has it that the first person to cross the Southern Alps from Hokitika to the Rakaia was a woman travelling alone. The pass she discovered became an important route for war parties and trade. In this excerpt from a new book, Uprising, Nic Low sets out on foot to determine how Raureka found her way through the mountains.
Anyone who’s spent a night in the forest knows that after dark the bush is a different and disorienting place. Distances seems greater, the air seems thicker, and sounds seems louder, as though nature dials up the volume knob after the sun sets. On a recent winter’s night, I went walking in Le Roys bush with Auckland ecologist Bella Burgess. We heard the rasping of wētā, the distant shrieks of pukeko from a nearby wetland, an animated conversation between a pair of ruru that we never managed to glimpse amidst the branches above. Beside the track, an exposed clay bank had become a galaxy of glow-worms, their tiny pale lights seeming to shine from an impossible distance. Then Bella switched on the ultraviolet torch she’d brought with her, and the bush came to life in a different way. Under ultraviolet light, tendrils of coral fungi lit up in neon. Lichens glowed silver. Mushrooms fluoresced bright yellow, orange and red, as though lit from within—and I was surprised how many I hadn’t noticed under the light of my headlamp. Some ferns had ultraviolet etchings on their fronds, while others of the same species didn’t. Was it a rust growing on them, perhaps? The way living things respond to ultraviolet light is poorly understood, but we do know that other animals—especially birds and insects—can see this extra colour. Our limited vision is the exception rather than the norm, and our animal and plant neighbours live in a world that looks quite different. One of the functions of this magazine is to show the world around us in a new light, and this issue, we’ve taken that literally, producing the first-ever ultraviolet-light photographs of a number of native bird species. These images are an attempt to approximate how birds see each other—not how humans see birds. It’s dizzying to look at, to glance up from the page and attempt to visualise what other species are seeing. What we can see has a impact on how we understand. “The relation between what we see and what we know is never settled,” writes the art critic John Berger in Ways of Seeing. “Each evening we see the sun set. We know that the earth is turning away from it. Yet the knowledge, the explanation, never quite fits the sight.” This issue of the magazine is about things that are hard to see, and about changes in sight. Nic Low writes about looking at a map of the South Island labelled only with Māori place names, the names that existed before Europeans arrived—so many names that the landscape shimmered with them like stars. He was struck by a sudden vision: the land wasn’t wilderness, as he’d always seen it. Rather, it was intimately known. At a more prosaic level, on page 76, Naomi Arnold learns that the view insurance companies take of the value of our homes may be quite different from ours. And on page 88, Dave Hansford grapples with the realisation that some trees might be... bad. Shifts of perspective are often prompted by religion, which photographer Cameron James McLaren investigates on page 58. Faith traditions give people a way of recognising and interacting with the unseen: the dignity of living things, the sacred nature of selfless acts, the invisible bonds of community and culture. McLaren’s photo essay offers a window into religious practice in our largest city, a look at how New Zealanders are approaching aspects of the human experience that can’t be photographed. With this being another issue finished under the protocols of a national lockdown, we’re all getting a new view of reality.
Humans can see three primary colours. Birds can see four. What does an ultraviolet world look like? And why did birds develop the colours they wear today?
The capital boasts mountain biking experiences as compelling as its coffee—many of them within pedalling distance from the city centre.
Participation in religion may be dwindling overall, but the practice of faith remains a highly visible and active component of New Zealand society.
A year of wandering the southern oceans, following ancient migration routes in search of food—that’s the tantalising glimpse of whale life that a tohorā/southern right whale nicknamed Bill has given University of Auckland researchers. Thanks to a satellite tag deployed by a team led by Emma Carroll in 2020, Bill has now provided the longest record of tohorā migration ever captured. Usually, satellite tags stop working after around six months. Bill’s tag, however, is still transmitting more than a year later. Bill left the Auckland Islands in August 2020 and travelled thousands of kilometres into waters south of western Australia, before moving far off into the Indian Ocean, almost halfway to Africa. Then, he turned south and swam thousands more kilometres to the Antarctic ice edge. Over several months, he worked his way back along the edge of the pack ice, finally returning to the Auckland Islands in June, having traveled well over 15,000 kilometres. Another tagged whale, Tahi, also travelled far into the Indian Ocean before returning to the Auckland Islands. “We had no idea that they were going so far west,” says Carroll. “Bill and Tahi went a third of the way around the world and back. That’s unprecedented. [caption id="attachment_432915" align="alignnone" width="600"] Photographer Richard Robinson floats above the seafloor holding a VR camera, waiting. The 80-tonne whales, curious and confident, are ideal subjects—approaching slowly, orbiting gracefully and drifting away when they’re satisfied they’ve got to know you.[/caption] “It’s showing that these whales are using far more of the ocean than we thought. Which is great, because if one area isn’t that productive, but the other is, they’re still getting a lot of kai. It suggests the population has resilience.” Carroll and her team have just returned from the Auckland Islands, where they deployed another 11 satellite tags. “We want to be able to match their satellite tracks against currents, productivity, marine heatwaves, and all kinds of things. At the moment, we can see what they’re doing, but we need more data to understand why they’re doing what they’re doing.” As for Bill, well, at the time of writing, he is still transmitting—currently halfway back to western Australia, off on another lap of his extraordinary life. His progress, and that of this years’ tagged whales, can be seen at tohoravoyages.ac.nz
Reconstructing the family tree of New Zealand’s blue-eyed shags has enabled scientists to unravel their past—and may help determine their future. The blue-eyed shag family includes bird species from all around the country: the rare king shag from the Marlborough Sounds, the Otago shag, the Foveaux shag, the extinct (but recently discovered) kōhatu shag from Northland, and species on the Chatham, Auckland, Campbell and Bounty islands, plus more-distant relatives on other subantarctic islands and in South America. Nic Rawlence from the University of Otago set out to track the evolution of the entire group, and his team’s genetic research revealed the birds evolved in South America. This is unusual for New Zealand birds, which most often arrive from Australia on the westerly winds. Blue-eyed shags were probably blown off course into the Southern Ocean and island-hopped around the subantarctic before arriving here around 2.5 million years ago and rapidly diversifying. That there are so many different species here is because of a paradoxical personality trait of blue-eyed shags. Though shags are obviously prone to accidental oceanic travel, once they find somewhere they like, they don’t stray far from home. That meant each small population was isolated from the rest and evolved independently. Then the ice ages struck, and Antarctic sea ice expanded all the way up to the more southerly subantarctic islands, spelling the end for the blue-eyed shags living there (the birds feed in shallow waters near their colonies, and when those froze over, they would have starved). When the ice retreated during a warmer period, blue-eyed shags recolonised the Southern Ocean from South America—but that later wave of migrants couldn’t get a foothold in New Zealand, as shags on the mainland had survived. “There were already blue-eyed shags that were happy, that were filling the job vacancy for blue-eyed shag,” says Rawlence. Genetic evidence confirms what biologists already knew about the family: “They are very, very prone to disturbance,” says Rawlence. “Whether that is human disturbance, polluting the oceans, or overfishing.” That makes them sentinels for the health of the Southern Ocean. “Working out how they evolved and how they’ve responded to past climate change can help us think about how they will respond into the future.”
Much of New Zealand’s coastal property has an expiry date, with its value set to be wiped off the ledger in as little as nine years’ time, well before sea levels rise and coastlines are redrawn. What will happen to marae and communities by the beach? And why are we still buying—and building—properties right in the danger zone?
You can buy a staghorn fern at any garden centre and grow it like a pot plant. But in the wild, the ferns grow in a way that’s changing our understanding of biological complexity. Latched onto branches of rainforest trees, staghorn ferns (Platycerium bifurcatum) evolved to live in colonies on Lord Howe Island off Australia’s east coast, with individual ferns fitted like puzzle pieces and working together to collect water for the benefit of all colony members. The level of job division is such that about 40 per cent of individuals forgo reproduction. Social colonies, with strict division of labour and reproduction, are nothing new in the animal kingdom, says Victoria University of Wellington biologist Kevin Burns. Social insects—bees, ants, termites and some wasps—are the best-known examples of colony-building behaviour, but it has also evolved independently in crustaceans (certain species of shrimp) and even mammals (naked mole rats). But Burns’ research describes the first time it’s been observed in plants. Colony-building behaviour, or eusociality, is the most recent of eight major evolutionary transitions to more complex life. Burns says eusociality is defined by colonies that include several generations of adults, and dividing labour and care for offspring co-operatively. Staghorn ferns may not fit the strictest definition, and are unlikely to have rigid job division like termites. “I suspect they go through a succession, starting off being a reproducer, then maybe a collector, and they shift as the colony develops,” he says. But the important point is that colony life is not restricted to animals. “Plants can walk that evolutionary path in the same way, without a brain—and that’s a huge leap forward.”
Tubenose seabirds—albatrosses, petrels, shearwaters and storm petrels—pretty much always follow the rules. Breed in the summer, when there’s more kai to catch. Mix up the length of foraging trips when feeding a chick: a few short foraging sessions for every long-distance feed. Mum and Dad pick different fishing spots and strategies, diversifying their options. Westland petrels break all the rules. They breed in the winter. Their foraging trips are always the same length—short, even though their wing structure means they’re capable of longer flights. And both parents fish in the same old spot. (Only 12 tubenose species are known to adopt these non-conformist habits.) To understand why and how Westland petrels successfully raise chicks with such an unusual approach, researchers tracked their movements using GPS loggers and accelerometers. The international team, including scientists from Te Papa, found that the Westland petrels were fishing around 150 kilometres off the coast, where the continental shelf slopes into submarine canyons: a reliable, local prey field that shapes their behaviour. Fishing peaks during the first few hours of darkness, suggesting that the petrels target bioluminescent fish and squid species that migrate daily up and down the water column. Westland petrels are endangered, and the small size of their foraging range—which coincides with a hoki trawl fishery—could pose problems in a food shortage, while their nesting burrows in the hills have previously been threatened by human development.
In the middle of July, a deluge dumped 690 millimetres of rain on Westport in 72 hours—more than three times the West Coast town’s monthly average. Houses flooded waist-high. More than 2000 people had to be evacuated and at least 100 homes remain uninhabitable. The downpour was driven by an atmospheric flow—warm air saturated with moisture. It’s the kind of event that’s becoming more frequent across the world, according to the latest climate update by the Intergovernmental Panel on Climate Change (IPCC), released in early August. It doesn’t make for cheerful reading. The report confirms that the world has now surpassed 1°C of warming since pre-industrial times, and that all emission scenarios will exceed 1.5°C sometime in the next 20 years. In the most optimistic scenario, warming will only surpass 1.5°C briefly, and temperatures will eventually drop back below 1.5°C later this century. To live in that scenario, we’ll have to bring carbon dioxide emission to net zero by mid-century, make deep cuts in methane emissions and then continue to strip carbon dioxide from the atmosphere. The report also confirms that climate change is now obvious across all lands and oceans, and that it’s our own doing. In its most strongly worded statement of culpability yet, it describes human influence on Earth’s climate as unequivocal and unprecedented. It says that 98 per cent of the warming observed since 1979 can be attributed to our global emissions. Atmospheric carbon dioxide concentrations are now higher than at any time in at least two million years. “Each of the last four decades has been successively warmer than any decade that preceded it since 1850,” it says. If temperature goes up, so will the world’s oceans, and the risk of extreme heat waves, rain and drought, the intensity of tropical cyclones, and the loss of ice, snow and permafrost. Sea level rise is one of a number of changes we can limit, but no longer reverse. Globally, we are committed to 0.4 metres by the end of this century, on top of 0.2 metres that have already happened, even in the best scenario. Beyond 2100, the process will roll on for centuries. For the first time, the report also includes regional updates. New Zealand is in line with global average trends and has warmed by 1.1°C, while Australia has warmed by 1.4°C. It’s perhaps no surprise that Australia can expect more intense and longer wildfires, but New Zealand, too, has recorded more days with extreme fire risk. The warming of the atmosphere is changing the global water cycle, with shifting storm tracks and wind patterns. One of the consequences for New Zealand is a strengthening of the weather divide: the West Coast will see more extreme wet weather like the Westport floods, while Northland can expect more drought and more intense ex-tropical cyclones. If there’s any consolation in the report, it’s the clarity with which it spells out what we need to do to stay close to 1.5°C of warming.
For many kiwi, there’s little chance of survival unless a ranger plucks them from the wild while they’re still in the egg. These birds hatch and grow up in captivity, then are returned home once they’re big enough to fight off stoats and rats. This system has saved the lives of hundreds of kiwi, but may have some unintended consequences: the microbes in the gut of kiwi raised in captivity are very different from those of birds which hatched in the wild. Kiwi chicks hatch ready to forage, says Manaaki Whenua microbial ecologist Manpreet Dhami. “From the very beginning they are digging around in the soil and foliage, looking for food and thus acquiring their first microbes.” Captive kiwi, on the other hand, are fed a mix of ox heart, cat biscuits and rolled oats—food that is “nutritionally appropriate but microbially a far cry from their natural diet”. If a bird catches an infection, it’s treated with antibiotics and then given probiotics to help restore its microbiome. Dhami and her team analysed faeces from wild birds and kiwi hatcheries, and found the microbiomes of wild birds were more similar to each other than those of captive birds—even when the wild kiwi were from different locations. The wild microbiome includes bacteria that may have a protective role against illness or help with food digestion, while the captive kiwi microbiome is simpler and less diverse. Studies on other birds—parrots, chickens and ostriches—have found a connection between less diverse microbiomes and a higher risk of disease. “As more and more birds go through the captive rearing process, we are creating a population of birds that are lacking that exposure to microbial diversity, and perhaps undercutting the development of natural defences,” says Dhami. Captive rearing is essential to the survival not just of kiwi but many other threatened birds, kākāpō and takahē among them. The team is now working on a new diet for captive kiwi—one that’s more natural and has more bacteria.
Do forests fall silent after a drop of the poison 1080? Scientists recorded birdsong in the Wairarapa’s Aorangi Range before and after 1080 operations in 2014 and 2017, as well as in the Northern Remutaka Ranges, which didn’t receive the poison. (1080 is intended to kill possums.) Analysing the hundreds of recordings, researchers from Victoria University of Wellington found birdsong levels were the same, or higher, in areas treated with 1080, compared to untreated areas of forest. The majority of birds were judged to be unaffected by 1080 on the basis of their calls, but two species were heard from less following the drops: chaffinches and tomtits. The researchers believe chaffinches, an introduced species, may have consumed 1080—the birds normally eat grain—and say further research is needed about how native tomtits may be affected by the poison.
Can you stop a cat from hunting? University of Exeter researchers tested whether improving a cat’s nutrition or exercise reduced its number of kills. Over three months, the researchers trialled different options on 219 households involving 355 cats in southwest England, focusing on interventions that increased the cats’ quality of life. Introducing high-meat protein food reduced the number of animals cats killed by 36 per cent, which supports the theory that cats hunt to compensate for micronutrient deficiencies in their diet. Cats who played with a feather toy for five to 10 minutes a day hunted 25 per cent less. Meanwhile, cat bells had no effect on hunting, while brightly coloured collars reduced the number of birds hunted, but not the number of mammals. (The cats didn’t like the collars, noted the researchers.) Use of a “puzzle feeder”, where cats had to solve a problem to access food, increased the cats’ hunting efforts by 33 per cent. To reduce the impact of domestic cats, write the study’s authors, “Owner behaviour is as important as cat behaviour.”
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