Turns out that looking at DNA can tell us a lot about what happened 125,000 years ago.
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Turns out that looking at DNA can tell us a lot about what happened 125,000 years ago.
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.”
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.”
Sea-level rise doesn’t affect coasts equally—one bay may be drowned while the beach next door remains the same as ever. Predicting sea-level rise needs to take into account tectonic movement of the land, prevailing winds, coastal erosion and Arctic meltwater. Now, the first-ever detailed map of New Zealand’s coastlines shows what may happen.
With its bright-red flowers shaped like a parrot’s beak, ngutukākā—also called kākābeak—is distinctive and delicious. Only 108 plants remain in the wild in Aotearoa, but many more grow in the United Kingdom due to the efforts of an English collector and gardener in the 1830s. Now, the descendants of these plants are returning home.
For generations, Samoan healers have been using the plant matalafi to treat inflammation, and illnesses caused by spirits or ghosts. So when Seeseei Molimau-Samasoni returned to her home village to collect plants for her doctoral research into traditional medicines, she was sceptical about matalafi. But of the 11 plants she analysed, it was the most potent. Matalafi (Psychotria insularum) is a member of the coffee family and grows throughout the South Pacific, but its use as a traditional medicine has been documented only in Samoa. Molimau-Samasoni consulted healers about how they prepared and used the leaf juice and pulp, and back at her lab at Victoria University of Wellington, tests on cells and in mice found that matalafi has an anti-inflammatory effect similar to ibuprofen, and that it affects cells’ iron levels. Working with Helen Woolner, who is Cook Island Māori, Molimau-Samasoni identified two iron-binding molecules with anti-inflammatory properties. Iron is an essential element, with an important role in cellular processes. While people are perhaps more aware of iron deficiency, says Woolner, iron imbalance or overload is associated with several serious diseases. She hopes to investigate matalafi’s effectiveness in the treatment of certain cancers and neurodegenerative conditions such as Alzheimer’s. Molimau-Samasoni is back in Apia, working at the Scientific Research Organisation of Samoa, where she leads a team looking into Samoan medicinal plants, soil microbes and marine organisms for any antibacterial, anti-gout or anti-cancer properties. “It is hugely important for Pacific people to lead research into Pacific traditional knowledge,” she says, “and Pacific natural or genetic resources.”
Off the east coast of the North Island, one tectonic plate slipping could lead to the same kind of quake that caused devastating tsunami in Japan in 2011 and Southeast Asia in 2004. Thanks to a suite of seafloor instruments and new underwater observatories, scientists are discovering more about this plate boundary and how it behaves.
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.”
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.
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.
Kea are the mischief-makers of the mountains, but a genome study shows they are not tied to alpine areas. As rising temperatures shrink their habitat, they could return to lowlands—if they can find suitable places to live. Fossils suggest that kea once occupied low-lying areas throughout the South Island and even in the North Island. In fact, there’s nothing “to stop kea from living at lower altitudes”, says University of Otago evolutionary geneticist Michael Knapp. The research scoured the genomes of kea and its sister species kākā, which is adapted to life in the forest, for any genes known to be involved in adaptation to life in the mountains. The commonly held theory was that kea and kākā went their separate ways about two or three million years ago, when the Southern Alps were still rising and opening up new alpine habitats. But Knapp says an ice age was redrawing the landscape at the same time, reducing forests in its wake. “For the ancestors of kea and kākā, their forest habitat shrank, and that made it more likely that some populations ventured into new habitats. That’s what distinguishes them—the kea is the species that went into the open.” The kea’s later retreat to alpine altitudes may have had more to do with avoiding people—including a bounty-hunting scheme that lasted more than a century, from 1867 to 1970, and killed some 150,000 birds. Thankfully, the genome doesn’t show a genetic bottleneck, which suggests the bounty-hunting period was short enough to avoid denting the birds’ genetic diversity, says Knapp. But the study has found a significant difference between the two parrot species. Kākā respond quickly to improved living conditions. When forest cover expanded in the past, so did kākā populations. In contrast, the kea population remained relatively constant, regardless of habitat changes. “Is the kea better at buffering bad habitats, or not so good at responding to good conditions?” asks Knapp. Both species may struggle to adapt to a warming world, says University of Otago PhD candidate Denise Martini. “If native forests begin to suffer from warmer conditions, it is very likely that kākā will suffer, too. Kea might be able to adapt to new conditions, but that depends on whether new conditions are available in the first place. My recommendation for conservation programmes would be to focus on restoring and preserving as much of the existing habitat of both species as possible.”
The emergence of a new coronavirus is not a question of if, but when and where—and a new study has answered the latter by mapping global regions most likely to produce the next outbreak. The research used horseshoe bats as a model, because they carry several coronaviruses from the same group that caused COVID-19, SARS, and a pig disease known as SADS. The study then connected the dots between several details: where the bats lived, forest fragmentation caused by expanding farmland, human population growth, and increasing numbers of livestock. Where all these things overlap, they “form a nexus where you might have really high risk”, says David Hayman, a Massey University infectious disease ecologist who was part of the international research team. The map—a swathe of horseshoe bat habitat from Spain in the west to the coast of Australia in the east—identifies China as a global hotspot, as well as Bhutan, east Nepal, northern Bangladesh and Thailand, all places where the next spillover event is most likely to transmit a virus from animals to people. In host animals, such viruses usually cause no harm; in other species, such as humans, the viruses can lead to severe and highly contagious disease. We know that if people encroach on wildlife, the risk of spillover increases, says Hayman. Our best chance of preventing such animal-human transmissions from growing into major outbreaks is to increase disease surveillance in high-risk areas. Heightened surveillance could also help contain outbreaks of existing spillovers, such as Ebola, which now re-emerges almost annually. But with a viral universe that likely includes millions of different strains, we need to think beyond pandemic preparedness. “If we really want to reduce the risk, then we need to look at the bigger things—what is causing forest fragmentation, and should we be putting another intensive farm with livestock in this area,” says Hayman, “because the same things that increase the risk of disease emergence also contribute to biodiversity loss and climate change.”
Don’t call them swamps. Bogs soak up and store more carbon than forests do, but when they’re drained and used for agriculture, that immense amount of carbon is slowly released.
Plants are our best technology for soaking up carbon dioxide from the atmosphere, but a new study shows the world’s forests and grasslands could flip over to become a source rather than a sink of CO2. Currently, the world’s green spaces absorb about a third of the emissions we produce by burning fossil fuels. But at the current rate of warming, plants’ ability to inhale more carbon dioxide than they exhale will slow down, then reverse, shrinking the carbon sink to almost half its size by as early as 2040. A study published in Science Advances in January looked at the link between temperature and photosynthesis (the process plants use to turn carbon dioxide and the sun’s energy into oxygen and sugars for their growth) and respiration (which releases carbon dioxide). Researchers analysed datasets from a global network of meteorological sensors known as FLUXNET, which tracks a suite of atmospheric variables, including carbon fluxes above different biomes. The study found that photosynthesis has a much lower ideal temperature, between 18°C and 28°C depending on the type of plant, than respiration, which means that as global temperatures continue to climb, photosynthesis will slow while respiration keeps rising. Some ecosystems in warmer parts of the world, including the Amazon, already reach this threshold during certain times of the year. Earlier studies on specific trees suggested that some would grow faster at higher atmospheric levels of carbon dioxide, but this wider study found no such effect. Nor did it find any evidence that plants adjust to perform higher rates of photosynthesis at higher temperatures. The results are a wake-up call, says one of the study’s authors, University of Waikato soil scientist Louis Schipper. “The biosphere has been harvesting our emitted CO2 and we assumed that would carry on. But this data shows the size of this terrestrial carbon sink will go down. It blows me away how near this is.” Add to this the increasing risk of wildfire and drought, and stressed plants’ lessened resilience to pathogens, and it’s clear, says Schipper, that we can’t count on “this idea of just planting trees”.
It’s one of New Zealand’s most important wetland habitats, and it’s also one of our most polluted lakes. Restoring it to its former abundance of birds and fish will take generations, but it’s possible.
In the past 50 years, the Raukūmara Range has seen dramatic changes—the forest has thinned out and native birds have vanished. Now, an iwi-led project plans to change all that.
Sixth-generation weaver Veranoa Hetet brings the strands of past and future together.
Since human arrival, this landscape has undergone dramatic changes—mostly in the form of losses. Here’s how we can protect and nurture what remains.
Race Relations Commissioner Meng Foon on growing up across cultures and tackling racism.
A unique New Zealand landscape is at risk of losing what sets it apart. Here’s what needs to happen.
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