The Alpine Fault ruptures—on average—every 330 years with a magnitude 8 earthquake. Geologists and authorities are racing to quantify what might happen, and how they might respond in the event of the next one, likely to occur some time in the next 50 years.
Like all of us, our nation began life cocooned in water. And as the Pacific plate drove into the Indo-Australian, Zealandia emerged from the waves, a new continent rising from the seas as if baptised. Ever since, this land mass has been pelted with rain borne by the westerlies that circle the Southern Ocean, and water has shaped the land, defined the natural history of this place, and in some ways also moulded New Zealanders themselves. We’ve become used to the damp. As is the national character, we’ve made the best of it, harnessing it to grow grass or to generate power. We’ve played in it, swum in it, drunk it and washed with it. Aside from the land itself, water is our most valuable natural asset. In fact, we may have taken it for granted. As the population increases and as demand for protein beyond our shores grows, we require more water than ever. Water turns the turbine of our economy, and the more we irrigate, the faster it spins. It takes 900 litres of water to produce a litre of milk, and nearly 4000 litres for a steak. Suddenly, 80,000 cubic metres of water per person every year—among the top 10 water-rich countries on the planet— doesn’t seem like quite enough. But the transformation of these islands has come at a cost—95 per cent of New Zealand’s lowland forests have been converted to pasture, and our mighty rivers have been diverted into power schemes and irrigation canals. Industrial wastes and town sewage have befouled our waterways, erosion and run-off have tainted them with phosphorus and nitrogen. Some rivers are among the most polluted in the world, toxic to aquatic life and no longer safe to swim in; aquifers that slaked the thirst of settlers are no longer potable. How did it go so wrong? This year has seen the publication of half a dozen reports on the health of our ecosystems, the commercial value of water and the cost to our environment of our industry. Each poses questions that will frame public enquiry into the next decade: How do we reconcile the unquenchable thirst of industry with the public amenity of water? How does ecosystem health figure in commercial rationale? And should it? New Zealanders care about their back yard as much as they do about the economy. So how do we learn to live in a land where there may not be as much water as we want, but we can have all the water we need? The special feature on water in this 125th issue is the first in a series of six major features to mark the 25th year of New Zealand Geographic. The past quarter century has been a period of great change for the country, and this magazine has been privileged to reflect that journey. In 2014, we will examine the concerns that will fuel the national discussion and shape us as a people for the next 25 years.
Take it from the pukeko, it pays to be honest
A new pest-control technique that affects only the fertility of males in a pest population could be a humane, non-lethal and effective solution to damaging populations of possums and rats in New Zealand. Published in the Proceedings of the Royal Society B, the Trojan Female Technique uses natural genetic mutations to render males infertile but leave females in perfect health. Subsequent generations of Trojan females produce infertile males, and still more Trojan females, until there are too few fertile males to go around. The technique has many benefits over other methods. It doesn’t require any genetically modified organisms, the pests spread the mutation themselves, it’s species specific and it can be adapted to any pest species. And, the process can be reversed by reintroducing normal females—important given that possums are endangered in their native Australia. Otago University scientist and lead author Neil Gemmell says that using the Trojan Female technique alone would take around 100 years to control the possum population, with large releases of Trojan females every generation too slow to arrest the damage occurring in New Zealand’s forests every day. However, a single release of Trojan females into an area following conventional controls such as trapping and poisoning would effectively cap the possum population, and lead to local extinction.
The lotus leaf sets the international benchmark for the ability of its leaves to repel water, but a study published in the Journal of the Royal Society of New Zealand classified some New Zealand natives as ‘superhydrophobic’—species of hebe (Veronica albicans), Euphorbia (Euphorbia glauca) and also the rengarenga lily (Arthropodium bifurcatum). Water droplets on leaves with rough surfaces touch only the waxy microstructures or epidermal cells sticking up from the surface, and the air pockets between them. The drops therefore can’t wet the actual surface of the leaf, and bead up even more than water drops do on a Teflon-coated frying pan. (The more tightly they bead up, the more ‘hydrophobic’ the surface.) Leaves of plants such as kauri or flax have no prominent structures sticking out from their surfaces and so are not hydrophobic at all. Lead scientist Geoff Willmott says that looking at superhydrophobicity in nature is valuable in the design of surfaces which need to remain clean, free of ice, or otherwise efficiently repel water.
Water, our most precious natural asset, offers amenity, a habitat for aquatic species and a focus for recreation. But it also turns the turbines of industry and powers New Zealand’s agricultural economy. Economic development and environmental integrity are at odds in a struggle for control over this great resource. Are we mortgaging our future for a little more economic growth?
. . . and why it continues. The view from 25.
Graeme Dingle looks back on a life of adventure.
A souvenir to foreshadow a society
This coastal track connects Colac Bay with Riverton and is mostly near the coast. For Te Araroa through walkers heading south, the excitement builds as the finish line comes into sight—while for those heading north, as they leave the southern coast the realisation sets in that it really is quite a long way to Cape Reinga! This route has been recently refurbished (November 2013) and is walkable for most levels of fitness and ability. The track formally begins at the Colac Bay Rd/Colac Bay Foreshore Rd junction. If you choose to walk this northbound, then further up Colac Bay Rd, the Colac Bay Tavern is a great place to reflect on your day, share stories and sample local delights. To do this track justice, time your walk around low tide so you can head east along the beach following the eastern shore of Colac Bay until the end of the sandy beach. From there, the marked track will take you in and out of the gulches and gluts of the Southland coast with views to Stewart Island. Waves and weather roll in off the Southern Ocean—keep an eye on the Longwoods (north of Colac Bay) as local legend has it that if you see them take on a blue-ish hue, rain is imminent. From the final deer fence the track leaves the coast and heads up towards, then through, Mores Reserve to emerge at a car park at the end of Richard St. There are public toilets here. Walk down Richard St towards Riverton. At the bottom of Richard St turn left onto Bay Rd and walk around to the Palmerston Rd Bridge. The Tihaka Beach Track ends at the far end of the bridge. Be aware that this section is closed during September and October for lambing. It is foot access only and dogs are prohibited.
Rust, lichen and wild Central Otago thyme combine forces to consume and cover the last traces of human industry at the Earnscleugh Dredge Tailings near Alexandra. Mined and washed of their gold from the 1890s, the river gravels have become a sanctuary for rare species, and one of the country’s most unusual wildlife reserves.
Warming makes destructive cyclones more common.
Science goes south, to Scott Base
Since the Immigration Act of 1987, migration from the Indian subcontinent has swelled Auckland’s suburban population, bringing with it a cultural cargo of music and dance that has coloured urban life and changed what it means to be a New Zealander.
A tribute to the contributors
Animals "eat without pleasure, cry without pain, grow without knowing it; they desire nothing, fear nothing, know nothing." - French rationalist Nicolas Malebranche, The Search After Truth and Elucidations (1674)
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