When the snow starts to fall on the Desert Road and clouds hang low over the Volcanic Plateau it's time for another intake of recruits to fall in at the army camp in Waiouru for a three-month introduction to military life known as "winter basic". Wellington photographer Paul Hitchcock joined the recruits each week to capture the pain and the pride of army life.
Natural historians in New Zealand have long been preoccupied with the antiquity and origins of our native land-dwelling plants and animals, especially our more distinctive icons, such as moa, kiwi and tuatara. New biochemical technologies are providing fresh insights into the genetic lineage of our flora and fauna, and hence their ancestry. But this information doesn't necessarily tell us anything about where the ancestral forms lived, or where the genetic changes took place. It is assumed that it was in New Zealand, but was it? This is a good question, for several reasons. First, the fossil evidence of our national iconic animals and birds is very restricted in terms of time: there are no known moa, kiwi or tuatara fossils older than two million years. Second, in terms of geological history, there may not have been any land at all within the New Zealand region about 25 million years ago. If the New Zealand landmass has emerged from the sea within the last 30 million years, then all of our native plants and animals have arrived and evolved since then. Such a scenario is almost unthinkable to contemplate. Conventional wisdom tells us that our native flora and fauna are descended from the "living cargo" that originally came with the New Zealand continent, Zealandia, when it split from Gondwana. But some geologists are now questioning that view. What is not in question is that New Zealand was originally part of the Gondwana supercontinent, and that it rifted away about 85 million years ago. It did so as a result of major thermal effects within the Earth's mantle that broke the crust asunder. Much of the granite in the South Island and Stewart Island relates to this thermal event. The chunk of crust that rifted away did not have the present-day configuration of the New Zealand landmass. It was much larger—about half the size of Australia—and is referred to as the "New Zealand continent" or Zealandia. It is amusing to recall that the early European explorers in our part of the world came here to search (in vain) for the great southern continent they called Terra Australis. If only they had known that it exists as Zealandia—largely submerged! An approximation of its size and shape, can be seen in bathymetric maps of the greater New Zealand region. What is impressive is not just the extent of Zealandia, but the fact that most of it now lies 1000 metres below sea level. Geological exploration of today's submarine part of Zealandia tells us that it was indeed dry land when it rifted away from Gondwana. The evidence is unequivocal: well beneath the sea floor there are sedimentary sequences with extensive coal deposits that could only have formed on land in low-lying forest and swamp environments between 70 and 50 million years ago. So what happened to make it sink? First, the thermally buoyant Zealandia cooled down. Sinking associated with cooling is perhaps more familiar with air masses in the atmosphere, but it is well authenticated by geologists in rocks as well. Second, Zealandia was either unusually thin to begin with or has become so. It is only about 25 km thick, not thick enough to be emergent as land. The thicker a block of crust, the higher it rides. Crust that underlies most of the oceans is only about 7 km thick, and the really high places on Earth are supported by 70-80 km of crust, such as beneath the Altiplano, in South America, and the Tibetan Plateau, in Asia. Within the context of Zealandia, it is the present New Zealand landmass that is anomalous. It could be said that the only reason it exists above water at all is because of the vigorous nature of plate collision between the Pacific Plate and Australian Plate that commenced less than 30 million years ago. This collision has literally pushed New Zealand up, creating all our mountain ranges in the process, and the forces responsible are still in action; still holding New Zealand's head above water. Terrestrial geological evidence also supports a largely submerged Zealandia, in the form of the wide spread occurrence of Oligocene limestone. Limestone is a white rock consisting of the skeletal remains of marine organisms ranging from plankton and algae to whales. It is largely devoid of sediments eroded from the land.Oligocene limestone, deposited between 34 and 24 million years ago, is best preserved in those parts of New Zealand that are well removed from the active plate boundary collision zone, such as in Northland and the Chatham Islands, but is best known in the King Country near Te Kuiti (Waitomo Caves), and inland north Otago and Canterbury. Pockets of it are preserved deep within the Southern Alps, near Queenstown, and in the nether regions of the Rakaia, Rangitata and Waimakariri River valleys of Canterbury, such as in the Castle Hill Basin. The distribution of this limestone is fascinating. Imagine a sheet of white rock mantling the whole of New Zealand, and which has now been eroded away so that only fragments remain. Extend the sheet again and imagine Zealandia totally submerged. A biological wipe-out. Just a few days of submergence, let alone hundreds of years (or thousands, or a million), would he sufficient to wipe the New Zealand slate clean and destroy all terrestrial life. With subsequent reemergence of land, life would become re-established, replenished primarily from the nearest land, notably Australia. By virtue of distance, birds would be among the first animals to arrive. Plants, insects, lizards, amphibians and mammals would have to take their chances. The idea of a clean slate in the Oligocene appeals to many geologists and paleontologists in that it may explain why there isn't a much greater diversity of animals in New Zealand today. When Zealandia split from Gondwana, dinosaurs turtles and flying reptiles were among the cargo, and surely the full spectrum of other Cretaceous land animals was present as well—mammals, lizards, snakes, amphibians—although we have as yet no fossil evidence of these. We know what put paid to the dinosaurs (effects of a major meteorite impact), but we need another mechanism to rid Zealandia, and hence New Zealand, of all other animals. Total submergence of the land would do the trick. New Caledonia can be thought of as a distal northern extension of Zealandia. Could it have been totally submerged in the Oligocene, too? The only known fossil-bearing sedimentary rock of Oligocene age in New Caledonia is, indeed, limestone. Like New Zealand, New Caledonia has a legacy of continental Gondwanan origins complete with Late-Cretaceous coal measures. Furthermore, the only native mammals in New Caledonia are bats, and it, too, has flightless birds and no snakes. The similarities are striking! Most geologists believe that the New Zealand land area in the Late Oligocene was greatly reduced, and some have suggested that it was only 18 per cent of the present area—a reduction that would have led to an evolutionary crisis in the terrestrial biota. Yet it remains possible that there may have been a period when there was no emergent land at all. The implications are considerable, so far as the origin of our New Zealand terrestrial species and ecosystems are concerned, and therefore the possibility warrants further investigation.
The endangered orange-fronted parakeet could be forgiven for having an identity crisis, since the debate over its taxonomic status has spanned three centuries. At issue is whether it is a true species or merely a colour variety of another more common parakeet. Subfossil records show that parakeets were abundant throughout the North and South Islands as far back as 20,000 years ago. Maori knew the three mainland parakeets—red-crowned, yellow-crowned and orange-fronted—collectively as kakariki. The first recorded mention of the orange-fronted parakeet was in 1857 by Charles De Souance, who named it Cyanoramphus maihehi from a single specimen, source unknown. The name was later discounted by Finsch, who deemed De Souance's specimen to be merely a yellow-fronted parakeet, Platycercus auriceps. Renowned ornithologist Walter Buller added to the confusion by claiming to discover the orange-fronted parakeet in the Southern Alps in 1869, naming it Platycercus alpinus, the alpine parakeet. This claim, too, was dismissed by Finsch in an article which stated: "two specimens, male and female, from the Southern Alps and marked as types of Mr Buller's supposed species are not distinguishable from the old known P. auriceps, either in size or colouring. These slight differences are by no means specific and only indicate the younger bird." By 1874, Finsch was eating his words:"Platycercus alpinus Buller is not the young of Pl. auriceps as repeatedly maintained by me, but a good species. I received old and young specimens of both through Dr Hector, which convinced me I was wrong." Such interchanges were typical of the late 1800s as various authorities laid claim to the discovery of new species or denounced their learned colleagues. There was, however, general agreement on the bird's rarity. "This pretty little parakeet I never found near a habitation, only on the mountains near the Alps in low thick scrub; it is a rare bird," wrote Andreas Reischek in 1885. Phillpotts, in 1919, noted their decline: "They were so tame that a boy with a shanghai could soon make a fair bag; but now it would be difficult to get within gun range." Doubts about the species' taxonomic status continued to be expressed throughout the 20th century, with various experts suggesting the orange-fronted was merely a colour variant of the yellow-crowned parakeet. In 1990, it was deleted from the list of New Zealand birds. Then, in 1995, the discovery of a substantial population of orange-fronted to have the same colour intensity, but the orange-fronted female seems to be a faded version of the male, which Kearvell likens to "having sat in the sun too long." "The orange forehead band is the crucial feature when trying to identify them in the wild," he adds. Although often heard in the forest, the birds can be hard to spot. The chatter calls of the two parakeet species are very similar, but orange-fronted parakeets have proved to be much quieter than yellow-crowns, making them even harder to find. "It is not unusual to be walking through the bush and to find a pair of orange-fronted parakeet staring at you, at head height, totally silent, just a few metres away," says Kearvell. Both parakeet species are highly active, non-territorial birds, restricted to beech forest. They spend most of their time in the canopy, but can be seen regularly on the forest floor, particularly when large quantities of beech seeds have fallen. As well as feeding on seeds, fruits, buds, leaves and flowers, the orange-fronted parakeet may be the biggest consumer of invertebrates of all New Zealand parakeets. "They can be very tenacious when they have located an insect inside a branch. They will spend considerable time and effort pulling the wood apart so that they can retrieve the nutritious prize," says Kearvell. In a beech mast year, a cyclic occurrence of heavy flowering and seeding, orange-fronts switch their diet to mainly beech seeds. They breed prolifically, even through winter, until seed supply runs out. The recent two consecutive beech mast years have meant that parakeets have probably been breeding more or less continuously for 20 months. In early summer of 2000, the floor of the forest in the Hurunui Valley was sprinkled with green feathers as numerous parakeets went through a major feather moult at the end of this breeding period. It is now possible that most parakeets will not breed for several years, until the next major beech mast arrives. Instead, they will roam the forests in large mixed flocks of birds, including both parakeet species, fantails (piwakawaka), yellowheads (mohua), brown creepers (pipipi), silver eyes and grey warblers (riroriro). An ecological study undertaken in the Hurunui during 1998 and 1999 discovered 25 orange-fronted parakeet nests. All but two were in mature red beech, with knot holes the favoured site for nests—some as low as three metres above ground level. Low-level nesting makes noisy nestlings and females incubating eggs particularly vulnerable to predation by stoats, rats and cats, but both sexes can be targets for predators when they roost for the night in holes. "The orange-fronted parakeet seems to be declining faster than the yellow-crowned parakeet," says Kearvell. "Yellow-crowns seem able to respond to a beech mast by breeding prolifically, but orange-fronts seem unable to increase their numbers to anything like the same extent." The total number of orange-fronted parakeets is estimated at somewhere between 150 and 500 individuals. There are 77 known specimens in museums around the world. Work on the conservation management of the species has begun. Predator control, in place in the Hurunui since 1995, was begun in the Hawdon in the summer of 1999, and trial transfer to a pest-free offshore island is planned. It is to be hoped that re-recognition of the orange-fronted parakeet as a separate species, and consequent conservation measures, can tip the balance back to a healthier ratio between live birds and stuffed!
A group of archaeologists and plant scientists have uncovered direct evidence of what plants Maori grew and consumed in pre-European times. They report on how they went about doing it.
The enduring popularity of Erick Brenstrum's weather column in this magazine is both a tribute to his skill as a writer and a reflection of our preoccupation with weather. In this column, deputy editor Warren Judd looks at how a thirst for weather inkmation can be quenched online.
Pushing through a field of brash ice, an intrepid New Zealand expedition closes in on the bottom of the world. Their goal: the Antarctic Circle. Their route: wherever wind, wave and ice permit a passage along the western shore of the Antarctic Peninsula. Their means: three fibreglass kayaks and a fair measure of grit.
In an age when rivers are managed to satisfy the competing demands of dozens of users, the raw power of a mighty river such as the Waitaki is rarely seen. Draining the central mountains of the South Island from Mt Cook National Park south to the Lindis Pass, the waters of the Waitaki—"water of tears"—now churn the turbines of a bevy of power stations before being siphoned off to irrigate dry plains closer to the coast. Here, 1000 cubic metres of water a second thunder across the spillway of Lake Benmore hydro station.
To 18th-century Europeans, accustomed to bleak weather, overcrowded cities, soul-destroying work and impoverished diets, Polynesia sounded like Paradise. A benign climate, food in abundance, a life of pleasure and ease such was the popular notion and European painters imposed no restraints on their imaginations when it came to depicting this distant wonderland. "Les peuples de l'Ocean Pacifique," a wallpaper design by J. C. Charvet, 1805, owed more to romantic notions of classical Arcadia than to anything which existed in the South Seas. Even so, the Pacific dream has proved remarkably enduring.
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