The gypsies themselves—lifestyle roamers rather than genuine Roma—relish the variety and unpredictability of life on the move.
The gypsies themselves—lifestyle roamers rather than genuine Roma—relish the variety and unpredictability of life on the move.
Frog populations throughout the world are continuing to decline, despite the best efforts by scientists in more than 30 countries to arrest the trend. New Zealand’s native frogs are no exception. Two of our four native species have recently been assigned the highest level of protection, as “nationally critical” (the same status as the kakapo), and one is “nationally endangered.” Some herpetologists believe that infection by a chytrid fungus may be the common link in amphibian decline (see New Zealand Geographic, Issue 54). However, whether or not this is a novel pathogen, causing a lethal epidemic in frog populations around the globe, or simply the last straw in a long line of insults that frogs have been subjected to in recent years (loss of habitat, acid rain and other forms of pollution, climatic and atmospheric changes) is still being debated. Chytrid fungi are unusual in that they have motile zoospores (almost like miniature tadpoles) that require the presence of water to move from host to host. They infect the skin of adult amphibians, causing chytridiomycosis, a fatal disease first found in New Zealand in 1999. It is unclear whether the fungi secrete a lethal toxin or affect the functioning of a frog’s skin. As chytrid fungi are probably recent arrivals in New Zealand, steps can still be taken to prevent their spread. Phil Bishop, an Otago frog specialist, says the public can help contain the pathogens by not releasing tadpoles or frogs into ponds other than those from which they were initially collected. “If people move from one frog habitat to another, or visit any offshore islands, they should ensure that they thoroughly sterilise any equipment that may contain potentially contaminated mud, such as boots, camping gear and tripod feet,” Bishop says. Frogs infected with the fungus may appear lethargic, fail to right themselves quickly and show unusual amounts of skin sloughing. Tadpoles may have difficulty swimming, show signs of internal bleeding or have swollen abdomens. To promote public awareness of the plight of frogs, herpetologists have declared October 5 to be International Amphibian Day. Auckland Zoo is planning a day-long event for the occasion, consisting of displays, workshops, live frog exhibits and talks by experts in frog biology. Similar frog displays will be mounted at other centres around the country during the week leading up to October 5. For further information, contact Phil Bishop, International Amphibian Day Coordinator, University of Otago, ph (03) 479-7990, email phil.bishop@ stonebow.otago.ac.nz. And don’t forget to eat semolina for dessert that day!
Scientists from Land Care Research in Hamilton and the Ministry for the Environment have developed a new way of looking at New Zealand’s environments, and it is winning awards overseas. Rather than mapping vegetation types or landforms, the new classification, called LENZ (Land Environments of New Zealand), is based on conservation, biodiversity and resource management. The team involved in the work—John Leathwick, Gareth Wilson, Daniel Rutledge, Fraser Morgan, and Malcolm McLeod started with a digital terrain map of the country, and used this to derive a slope layer, the first of 15 data sets or layers used in the classification. Among the other layers are seven sets of climatic data, including annual and winter solar radiation (indicating how much light is available for plant growth), mean annual temperature, mean minimum temperature of the coldest month (a frost indicator), annual soil water deficit (an indication of whether drought is likely to be a factor), average monthly ratio of rainfall to evaporation (an indicator of how wet a site is) and vapour pressure deficit (a measure of the dryness of the air). To the climatic information the team added seven landform parameters: drainage, age of soil formation, levels of phosphorus and calcium (important indicators of soil fertility for plants), parent rock resistance to weathering, particle size at the depth where rock and soil meet (this determines speed of soil formation and nutrient release), and chemical limitations to plant growth (such as highly saline or ultramafic soils, where only certain plants can grow). All of these data layers were combined and analysed in a numerical classification program that grouped sites with similar attributes into environments. The program delivered 800 such environments—too many to be handled practicably. To make the results more manageable, the similarities between all of the environments were calculated and the most similar pairs were merged. The result is four master sets of environments, ranging from a 500-environment set for the most detailed viewing of small parts of the country to a 20-environment set suitable for mapping the whole country. To improve the resolution of the final products, every point on both a 100 m by 100 m and a 25 m by 25 m grid across the whole country was assigned to an environment at each of the four levels. The distributions of the four sets of environments can be plotted in a geographic information system to produce actual maps, but were designed primarily as a framework for councils and governmental organisations which monitor and report on the state of New Zealand’s environment. What does the LENZ classification have to offer that the old vegetation maps don’t? An ability to peer back in time, for one thing. Over large tracts of the country, native vegetation has been replaced by grassland, introduced forest or scrub, making it hard to know what once grew there. By identifying environment‑mentally similar sites with indigenous plant cover intact, this new tool can give a very good indication of what the original plant communities would have been like at any location. Suppose a rare native lizard is found in a particular environment, but is under threat there. The LENZ system can identify similar areas elsewhere, where the lizards could be transferred to start a fresh population. The system can also help those trying to limit biosecurity breaches. With the southern saltmarsh mosquito (carrier of the debilitating Ross River virus) currently established around Hawkes Bay, Poverty Bay and the Kaipara, LENZ can identify other warm saline habitats to which the mosquito might spread. Want to produce Bordeaux-type wines in New Zealand? If you know the soil and climatic details of the Bordeaux region in France, with LENZ data you can determine the location of all environmentally similar areas in New Zealand. Two books on LENZ are being published: a broad introduction to environmental classification that will contain general information on New Zealand’s climate and landforms, and a more detailed technical guide for serious users. However, the main output of the project will be the LENZ digital dataset, for use by those with system (GIS) software: regional councils, DoC, MAF, geographers, agriculture and forestry companies. For such groups, LENZ should prove an invaluable tool for years to come.
Palaeontologists in this country face a problem. Despite an extensive marine fossil record that includes some of the world’s best examples of marine vertebrates, such as whales and penguins, the record of terrestrial vertebrates is pitiful. We have dinosaur fossils from about 70 million years ago (Ma)—not long after New Zealand split from Gondwana—but over the huge gulf of time between then and 100,000 years ago, there are few fossils of land animals. We have an abundance of fossils from the last few tens of thousands of years back to 100,000 years ago, but they are all species that either exist today or became extinct following human arrival. As a consequence, very little is known about what animals might have lived here over the past 80 million years, and hypotheses about the origins of our existing terrestrial vertebrate fauna are difficult to test. Recent discoveries in Central Otago, however, may alter the palaeontological balance sheet. For some time, it has been known that a large freshwater lake, known as Lake Manuherikia, existed in this area, dating from the lower to mid-Miocene, some 20–15 Ma. The characteristic white sediments that betray the lake’s existence are perhaps most famously exposed in the gold fields about St Bathans, but they can also be seen about 50 km away at Bannockburn, near Cromwell—so it must have been a large lake. Abundant macro-and microfossil remains of plants provide a detailed picture of the environment at the time: the climate was some 7–80 C warmer than at present, and plants we take for Australian natives—eucalypts and casuarinas—along with palms, lived around the lake, along with many other scrub and rainforest species. Modern taxa such as fuchsia, supplejack, flax, kamahi, red and silver beeches were also present in the region. The remains of animals living in the lake’s vicinity were first discovered by Barry Douglas and Jon Lindquist in 1978. Further material was collected by Ewan Fordyce and others in the early 1980s, including, among the many fish bones, about a dozen bones of at least two kinds of waterfowl. Views about what taxa were in New Zealand’s palaeofauna received a jolt in 1997, when Ralph Molnar and Mike Pole reported a crocodilian bone that Pole had found in these same lake sediments in 1989. Where there was one crocodilian bone there were bound to be more, so the stage was set for a re-examination of the sediments. In December 2001, Jim McNamara (South Australian Museum), Craig Jones (Institute of Geological and Nuclear Research), Alan Tennyson (Museum of New Zealand/Te Papa Tongarewa) and Trevor Worthy (Palaeofaunal Surveys), visited the area and began a specific search for fossil vertebrates. Their method was to locate a layer in which bones had accumulated, remove the sediment and wash it through screens to concentrate the fossils. Big bones were immediately obvious, but most of the “good stuff” was only revealed back in the lab, where many hours were spent picking tiny bone fragments from the silt. The researchers found fossil vertebrates other than fish in three distinct sites and in different strata at two of the sites. The remains were surprisingly abundant. Apart from thousands of fish bones, at least a couple of hundred potentially identifiable non-fish bones were recovered. Among these—and of considerable interest—were the remains of several reptiles. The crocodilian gained a few teeth and skin osteoderms (scutes) to add to the single cranial element previously found. Even so, we still lack something diagnostic by which to relate the animal to other crocodilians in the south-west Pacific, including those now known from New Caledonia, Vanuatu and Fiji, in addition to those from Australia. A tiny bone fragment bearing three acrodont teeth (teeth which are part of the jaw, rather than insertions or additions) suggests tuatara ancestors were present. If confirmed as sphenodontid, this discovery would be the first fossil record of the group between the end of the Cretaceous, 65 Ma, and the Recent to be found anywhere in the world. But the real surprises were two fragments bearing snake teeth. Snakes, of course, are not part of New Zealand’s terrestrial fauna, and have no previous fossil history here. But these tiny remnants clearly indicate that snakes lived with crocodilians and ancient tuatara in the Miocene. Also discovered were fragments from two kinds of bat, which preliminary work suggests were related to our mystacinids, or short-tailed bats. Along with these various reptile and bat remains were relatively abundant bones of at least a dozen types of bird: five types of waterfowl, a couple of waders, four passerines, or songbirds, a crake-sized rail and a parrot. Bird eggshell was common, and some of it may even belong to moa ancestors. None of these taxa are the same as any that are living today. So, New Zealand finally has a Cenozoic record in the form of a diverse fossil fauna that reveals what terrestrial vertebrates lived in New Zealand for at least one period prior to the Recent. The study of this fauna has just begun, and it is to be expected that many more surprises are yet in store. But the question about how much of the present fauna was derived from Gondwana at the time New Zealand split away 82 Ma, and has been resident on this land ever since, is beginning to get tangible answers from the rocks. Similarly, suggestions that various components of our fauna are the result of recent colonisation by over-water dispersal may face a challenge from the fossils. The “Oligocene bottleneck” hypothesis argues that the extensive submergence of New Zealand during the Oligocene (30–24 Ma), when land area was reduced to about 18 per cent or less of what we have at present, filtered out much of the diversity of life New Zealand took with it from Gondwana. But the animals revealed in Central Otago’s fossil lake already challenge this idea. Snakes and crocodilians clearly survived here after the great inundation, but now they are gone. The questions of when and why they disappeared will occupy palaeontologists for a while yet, but it seems likely that the evolution of some of New Zealand’s unique endemics may yet get a fossil history.
The term “weather bomb,” used in June of this year by forecasters in relation to a rapidly intensifying storm that was approaching New Zealand, struck a chord with the media, which trumpeted the warnings so loudly that few people would have missed the message that there was serious trouble on the way. When it hit, the worst effects of the storm were felt across the northern half of the North Island, especially the Coromandel Peninsula, where up to 270 mm of rain fell in 24 hours in the ranges near Thames. The heavy rain turned the steep streams on the western side of the hills into raging torrents. One elderly woman lost her life when she was washed into the sea by the flooded Waiomu Stream as it crashed through a campground, uprooting trees and upending caravans. Her husband narrowly avoided the same fate when he managed to cling to a tree until a neighbour, with a rope tied round his waist, struggled through the torrent to rescue him. Another woman was washed out to sea on top of her caravan. The caravan eventually sank, but the woman managed to reach the shore safely. Many residents of the nearby Thames Coast settlements of Tapu, Taruru and Te Puru had to abandon their homes when they were invaded by silt-laden floodwaters. Power was cut to thousands of homes, and sewerage and water-supply systems failed in Thames. Around 350 homes suffered damage, and a state of emergency was declared. A man on Great Barrier Island had a narrow escape when his car stalled as he crossed a flooded culvert. He managed to jump from the vehicle as it was washed away, and watched in amazement as it disappeared in the floodwaters with its tail-lights still on. The next day he found the car 400 m downstream. Northland also experienced considerable flooding, with up to 240 mm of rain falling in some places in 48 hours. The Mangakahia River, north of Dargaville, peaked at 11.5 m above normal—the highest for 15 years—while at Ahipara a flooded stream cut a new route through the sand dunes to the Tasman Sea. In Whangerei a family fled from their home seconds before a large slip tipped it from its foundations and sent it crashing down a slope on to their car. The Dargaville Fire Brigade had to use a 4WD tanker to rescue a man trapped on the roof of his car. when it stalled in floodwater on a low point on State Highway 12. Further down the road another man was fortunate to escape with only cuts and grazes when a pine tree crashed across the bonnet of his vehicle. Easterly gales brought trees down over electricity supply lines, cutting power in many places, while at Maungaturoto the wind fanned a house fire and tore roofing iron from the blazing building, creating an extra hazard for fire fighters. Meanwhile, in Auckland a man was crushed by a falling tree, and power was cut to thousands of homes. A skylight blew in at a Takapuna shopping mall, showering about 30 customers seated at a café with glass shards. A state of emergency was declared in the Waikato, where a silo was blown over, dozens of houses lost their roofs in the high winds and power lines were severed in many places. Flooding in Putaruru forced some residents to evacuate their homes in the dark. A front-end loader was used to rescue one woman and her baby when their home was cut off by floodwaters. The Bay of Plenty also suffered from the weather bomb, with roofs lifted, windows blown in and power cut to over 20,000 homes by falling trees and flying debris. In Whakatane, the port’s own vessel was sunk. Further south, in Hawkes Bay, there was only minor wind damage, and the moderate rainfall brought a welcome end to a long dry spell. As the low moved south-east it delivered a parting blow to the upper North Island in the form of a southwest gale, which knocked over more trees, causing further power cuts. A gust of 144 km/h blew 16 containers off a ship in the port of Tauranga, closing the port until they could be retrieved. The use of the phrase “weather bomb” to describe the storm excited a certain amount of controversy. Some people thought the storm should have been treated as a tropical cyclone. However, it did not exhibit the internal structure or behavior of such an event. Others objected to the word “bomb,” assuming it to be a newly coined, attention-grabbing term more suited to the world of advertising than that of meteorology. In fact, the term “bomb” has been used in North America for more than 20 years to describe rapidly intensifying lows, some of which have been known to deepen by 60 hPa in 24 hours off the east coast of the United States. One definition of a bomb is a low that deepens at a rate of 24 hPa in 24 hours at latitude 60°. When adjusted to the latitude of Auckland to allow for effects caused by the curvature of the earth’s surface, this is the equivalent of 17 hPa in 24 hours. The problem with relying on the pressure fall to measure intensification is that most bombs are moving rapidly poleward, into regions where the background pressure is low. A low that is 10 hPa below the surrounding pressure in the latitude of the North Island may fall by 25 hPa as it moves rapidly south-east yet still end up only 10 hPa lower than the surrounding pressure near Antarctica. Such a low would undergo little change in vorticity—the energy of the air moving around the storm centre. New Zealand weather scientist Mark Sinclair believes that vorticity is actually a better measure of a storm’s intensity than drop in pressure. He has found that the area just to the east of New Zealand is one of the most active for bombs in the Southern Hemisphere. Indeed, as I write this, another bomb is moving through this active area, just far enough away to have little effect on our weather except for a day or so of enhanced swell along the coast from Gisborne to Wairarapa. The list of atmospheric ingredients necessary to cause a low to deepen rapidly—or explosively, as it is sometimes described starts with strong upper-level divergence. Wind patterns that cause the air to spread out, or diverge, at altitude act to lower the sea-level pressure by removing air aloft. This typically happens when a fast-moving upper trough interacts with the subtropical jet stream, that ribbon of 200 km/h winds frequently found just north of New Zealand. The second vital ingredient is surface air with high water-vapour content, as typically occurs in the tropics and subtropics. As this air rises in the developing low it releases massive amounts of heat as the water vapour condenses to form liquid cloud droplets. This heat helps to deepen the low and also to change the upper wind patterns in a way that increases divergence, thereby further deepening the low. Ten years ago, the computer models used to forecast the weather struggled with bombs. Now they are much better, partly because of better physics in the models, and partly because the computers are more powerful and can work at a much higher resolution. As a result, the June bomb was forecast well in advance of its arrival, and farmers and others could take precautionary measures. It is interesting to note that all the warm subtropical air brought down to New Zealand latitudes by the storm helped to make this June one of the warmest on record, despite major snowfalls to low levels in parts of the South Island. In fact, the national average mean temperature of 9.8° C was 1.5° C above normal. As they say, it’s an ill wind.
Crimson mistletoe blossoms were once a summertime feature of New Zealand’s beech forests, but the showier species are now scarce, and carpets of fallen flowers—such as here, on the Circle Track in Fiordland, where Department of Conservation officer Freddie Hughes explains the mistletoe story to walkers—are a rarity. While the appetites of possums have played a part in mistletoe demise, other culprits have recently been implicated.
Built in the 1920s as a memorial to local Maori who died in the First World War, St Mary’s church in Tikitiki, near East Cape, has been a place of commemoration and worship for more than 75 years.
During the summer of 2002, kakapo on Codfish Island/Whenua Hou, off the north-western coast of Stewart Island, bred with unprecedented success. Of 26 chicks hatched, 24 survived, boosting total kakapo numbers to 86—the highest they have been in 20 years. For the more than 100 volunteers who watched over eggs and chicks while the mother birds foraged for food, caring for kakapo was no easy assignment. It entailed a twice-daily slog along steep, boggy tracks and nights spent alone in a tent in the forest. But nest minders such as Hamish Downer, here getting his boots well immersed in the local mud, and Sue Bolland, lifting a 24-day-old chick out of its nest-box for weighing, had only one word for the chance to take part in the restoration of the kakapo’s fortunes: priceless.
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