New Zealand Natural History

Geology

Geology | Flora | Fauna | Birds | Marine Mammals

Geology

Gondwana
Southern beech trees (Nothofagus), which also occur in Australia, New Caledonia and South America (and used to be in Antartica), are quite different from the northen hemisphere beeches. The distribution of the southern beeches was a major piece of evidence supporting the concept of continental drift. Beech seeds do not survive in the ocean, are too heavy to spread by wind, and are not carried by birds, so could not have spread between continents. Therefore beech must have spread when the southern continents were joined together as Gondwanaland, 80 million years ago.

Karst landscape
The tablelands of the north-west South Island are a remnant of once extensive sea-level plain which over 45 million years ago stretched across New Zealand. In the last 14 million years the plain has been uplifted. It is made of marble and limestone. Limestone is mostly calcium carbonate, which came from the skeletons or shells of small sea animals which settled on the sea floor millions of years ago, and were compressed to form rock. It is often rich in fossils. Marble is limestone which has been metamorphosed by high temperature or pressure deep within earth's crust into a harder rock. Together limestone and marble constitute 5-10% of the earths surface. Karst is a term for a limestone landscape and comes from a region in Slovenia. Under the eastern flank of the Mt Arthur Range, two very large cave systems have been discovered: Ellis Basin and Nettlebed. The entrance of the Nettlebed was discovered in 1969, and, over the years, 25 kilometres of passages have been mapped by speleologists. From the cave's highest opening (Blizzard Pot) to its lowest level is 889 m, making it New Zealand's deepest cave. Ellis basin cave system is longer, but not quite as deep as Nettlebed, though new sections are still being discovered. Mt Arthur is hard crystalline marble, and nowhere else in New Zealand is there such a complex series of ancient rocks eroded into such distinctively different landscapes. Ice ages carved out cirques high on Mt Arthur. Caves are formed when limestone/marble is dissolved by water. Water with dissolved CO2 is slightly acidic, more so when tannins leached from the forest are in it. It reacts with CaCO3 gradually dissolving it, and carving caves where streams flow through fissures in the rock.

Paparoas
The Paparoa range – a backbone of rugged granite peaks and a lowland belt of limestone, carved by water into canyons, caves, and sinkholes. Sheltered by mountains and nurtured by a warm moist ocean current, this area has a subtropical microclimate with lush vegetation, giving the appearance of tropical rainforest.

Stalagtites
As water dissolves the limestone it becomes saturated with CaCO3. When the saturated solution drips from the roof, any evaporation of the water causes the CaCO3 to precipitate out of solution i.e. it becomes solid again. This can cause a stalagtite to form at the point the water drips from, or a stalagmite to form on the ground where the drop lands. A range of shapes can form by variations of this process: straws, pillars, curtains.

Pancake Rocks
Limestone, formed by sedimentation of shell debris, accumulated and compressed over millions of years, and then uplifted. The sea then forced it’s way under this geological formation, creating surge chambers and blowholes, that can explode with extraordinary power in the right weather conditions. Also wind and waves have sculptured a range of towers, pinnacles and faces in the rock.

Glaciers
Glaciers are rivers of ice which are fed by snowfall at their head, and flow down valleys until they reach a lower altiltude where it is warm enough to melt them. North west winds pick up moisture from the Tasman Sea and bring 15 metres of rain at 1500m, which delivers 45m of snow at 2500m. The accumulation of snow feeds the Fox and Franz Josef glaciers, two of the few in the world which come right down into rain forest. Fox and Franz are special because of the low level snouts and speed of movement. During 1965-67 the glaciers advanced 1-8m a day. The neve is the top part of the glacier, the huge collecting snow-field. New snow compresses the air out of old snow to form firn, which in turn is compressed further into blue ice. Gravity shifts the mass downward, and under the strain crevasses appear, which are the distinctive linear cracks that cross the glacier, especially where the incline increases, or there’s a corner. Where the glacier is squeezed at the narrowest and steepest part of its descent you will see the ice-fall, a mangled bunch-up of crevasses and seracs, isolated pinnacles of ice. Rock that has been crushed and dragged down by the glacier is called moraine. It collects at the sides of the glacier, on the surface, and at the terminal. Often, glaciers have terminal lakes, though this is not the case with the Fox and Franz glaciers, where you can the see the river gushing out from an ice-cave directly under the glacier. The ‘milkiness’ of the river is caused by glacial flour, which is a fine mass of silt and grit eroded by the glacier. Franz Josef Glacier was named after the emperor of Austria by the surveyor/geologist/explorer Julius von Haast. Haast named many mountains after his friends back home. The Maori called it Ka Roimata o Hinehukatere ‘the tears of Hinehukatere’. Fox Glacier has it’s own name, Te Moeka o Tuawe ‘the bed of Tuawe’. There are glaciers on almost every continent of our planet, covering 11% of the land surface and locking up 90% of the above ground freshwater (85% is in Antarctica alone). Only Australia supports no permanent ice today. New Zealand has 3153 glaciers, except for 18 on Mt Ruapehu, all are scattered over the Southern Alps, comprising some 116 sq km of ice.

Fiordland has been shaped by glaciers. This is evident from the shape of the valleys, which are U-shaped meaning they have steep walls and broad flat floors. In contrast, valleys carved by rivers are described as V-shaped. The glaciers in Fiordland were carving these valleys during the last ice age, 20,000 years ago, when the sea level was 100 m lower due to much of the water being locked up in ice. When the climate warmed, the glaciers receded to the mountain tops, leaving deep troughs which filled with water forming the lakes. Also sea levels rose flooding some valleys to form the fiords e.g. Milford Sound. Much of Fiordland is made of very old hard rocks (metamorphic e.g. gneiss; plutonic eg. granite), hardened by pressure and heat beneath the earths crust then uplifted. Thus the steep valley walls cut by the glaciers have been slow to erode further and so remain near-vertical, giving the place its stunning topography.

The Tasman is NZs largest glacier at 28 km long and up to 3 km wide. It once extended another 50km to the end of Lake Pukaki, which filled as the glacier receded. The Tasman glacier is up to 600m deep, and at the snout, still some 200m thick, the ice is 500 - 800 years old. It fell as snow long before Abel Tasman caught the first glimpse of the craggy skyline of the Southern Alps. Most people are rather disappointed at the ‘absence’ of the Tasman glacier. Instead of seeing a splendid vision of a crystal-white river, with ‘icebergs’ calving in a deep blue lake, the visitor sees a huge pile of rubble, finishing in a grubby lake and a thick dirty river. The glacier is there alright, and the rubble is only a metre deep in places, on top of 200m of ice. All glaciers are huge grinding mechanisms, carrying large amounts of mountain debris to the plains. Some of this material is held suspended in the glacier. Because this glacier is receding, the debris is much more evident. The terminal lake of the Tasman Glacier was only a few sinkholes twenty years ago, and a fifty years ago you would have had to walk up from the road to get onto the glacier. The lake is likely to go on increasing in size quite rapidly.

The Hooker and Mueller glaciers illustrate well glacial features such as lateral and terminal moraines, and the terminal lakes created by recession of glaciers. The Hooker river shows the cloudy grey colour imparted by glacial flour, the fine rock dust ground by the glacial movements. This flour at lower concentrations gives lake Pukaki its bright opaque turquoise colour.

Greenstone
Pounamu is a term applied to nephrite, known as jade in other countries, which is found in the Arahura and Wakatipu regions, and in many rivers and beaches between Jackson Bay and Martins Bay, and bowenite (which is a type of serpentine) found at it’s most significant site at Anita Bay in Milford Sound. Bowenite is lighter in colour and called by the Maori ‘tangiwai’ meaning ‘tear water’. The exceptional hardness of greenstone made it highly desirable for weapons of war, and its beauty, desirable for ornaments. One account refers to greenstone as ‘kai kanohi’, ‘food for the eyes’. The Maori recognised several types of greenstone – kahurangi (light coloured), kawakawa (dark coloured), inanga (whitish, sharing the same name as whitebait) and tangiwai (transparent). Only in the South Island could the valued mineral be found, and the most abundant source was in the Arahura and Taramakau valleys. The Maori had regular trails and knowledge of the Haast Pass, Browning Pass, Harper Pass, Whitcombe Pass, and Lewis Pass. Greenstone is not always obvious in it’s natural state, for usually there is an outer rind of rock that could be anything from almost white to deeper browns. The Maori traditionally looked for greenstone when it was wet, after storms or an outgoing tide, when the greenstone was more easily distinguished. Often some of the best greenstone pieces can be found on the coast, as they have survived the natural ‘grinding’ mechanisms of river and shingle. The milky-green inanga was particularly prized by the Maori.

Hot Springs
There are over fifty hot springs or seepages throughout the South Island, mainly associated with the Southern Alps and the Alpine Fault. This fault line is the consequence of the two tectonic plates that New Zealand sits astride, and literally moves mountains, such as the Red Hills; one part is still in South Westland, while the other has been slid up to Nelson. There are two commercial hot springs in the South Island, both on the Lewis Pass road, at Maruia Springs and Hanmer Springs. Natural hot pools contain microorganisms which are adapted to life at high temperatures – they have special heat stable proteins (enzymes) which can carry out the biochemical reactions on which life depends at temperatures which would destroy the proteins of most organisms. Some of the green slime in the pools is an algae called blue green algae (or cyanobacteria) which is the most simple primative type of algae i.e. one of the earliest types of plant which evolved. It can photosynthesize but its cells don’t have nuclei, which is a characteristic of bacteria rather than algae.

Southern lakes
Lakes Wanaka, Hawea and Wakatipu all lie in hollows carved out by glaciers 20,000 years ago, and the surrounding hills shows the rounded forms sculptured by glaciers i.e. hillsides smoothed and contrasting with the jagged peaks above. Look out for roches moutonnees (sheep shaped rocks) isolated rounded hills with a smooth side where the ice rode up and a rougher steeper side where the passing ice plucked out pieces of rock. This area was opened up by gold prospectors in the 1860s, then settled by high country sheep farmers. More recently it has become a popular recreational area with trout fishing and boating on the lakes and rivers, tramping in the mountains, and skiing in winter. Numerous vineyards have sprung up in the last 20 years taking advantage of the hot dry summers, gentle autumn conditions, and plentiful irrigation water.

Landslide
The Green Lake landslide in Fiordland National Park, may be the largest of its type on earth. (Surpassed only by submarine and slow creeping slides). It covers an area of 45 sq.km and the volume of earth that moved was 23 cubic km. The landslide occurred about 12,000 years ago and was probably due to an earthquake. A 9km segment of the Hunter mountains moved 2.5 km laterally and 700m downwards, creating a landslide dam 800m high. It formed an 11 km long lake which has since been filled in by glacial sediment, through which the Grebe river now flows. The debris formed the shelf which now holds Green lake and Island lake.

Tussock basins
On the shelf of landslide debris holding Green Lake and Island Lake are other depressions where tussock grows rather than beech forest. These may be old lake beds which have since silted up and infilled, where beech has not yet had time to establish. But there is another possible reason that beech forest does not grow there. These basins trap cold air forming a temperature inversion, so that although they are below the bushline, it is too cold for beech forest to grow. This is well illustrated by frosty nights spent camping at Green Lake – remember it is warmer camping under the beech trees.

Fossilised forest
The fossil forest at Curio Bay is one of the most extensive and least disturbed in the world and the processes that brought the trees to this state and left them ‘beached’ on the remote and tranquil Catlins coast, were complex, and almost entirely violent. The fossilised forest has a history that goes back to Gondwanaland. This ancient super-continent comprised much of Antarctica, Australia, Africa, India and South America, and existed about 180 million years ago. Curio Bay forest then would have looked similar to New Zealand rainforest today - luxuriant ferns, and trees like kauri and matai. A few dinosaurs, but no birds, and much of modern New Zealand at that time was under water. Volcanic activity repeatedly buried the forest with ash, then new forest grew, and then another reburial. This happened at least four times, and then these sediments were buried deeply and silica minerals invaded the woody tree stumps and quite literally turned them to stone. Finally, the rock was brought to the surface, and eroded by the sea to expose the fossilised tree stumps - a remarkable transformation.

Schist tors
Central Otago is a fragmented schist plateau, characterised by dramatic schist tors. The huge grinding process of weathering does its work unevenly, and some schist rocks are better at resisting than others - hence these columnar tors. Lichens have seized a hold on the rocks with some striking colours, in contrast to the brooding, almost sinister shapes of the tors.

Scree
The Central Southern Alps are made of a rock called greywacke, which weathers quickly. Its numerous cracks and weaknesses take up water, and when this freezes and expands, the rocks are fractured. The result is scree – a slow moving conveyor belt of rock debris. This is a unhospitable environment: unstable and subject to extreme temperatures. The plants which manage to survive on scree often have deep roots which reach down below the layer of mobile rocks into underlying moist sandy soil. The roots store reserves of energy so that if the surface parts of the plant are damaged, new parts can be grown. Colouration may be cryptic (blueish grey) to hide the plant from grazers, and surfaces waxy to prevent dessication.

Volcanic rock
Mount Somers is an old volcanic rhyolite dome, quite distinctive from the greywacke that makes up most of South Canterbury. It is not an actual volcanoe (like Ruapehu) but magma squeezed up through a crack. The hard volcanic rock of Mt. Somers withstood glaciation, and has created an interesting topography with rock outcrops, waterfalls, and narrow gorges.

Canterbury Plains
The largest plains in NZ (300km x 100km). Geologists estimate that less than a million years ago the waters of the Pacific Ocean lapped against the base of the Southern Alps, but slowly, by glaciation, and by the action of the great braided rivers (Waimakariri, Rakaia, Rangitata), the mountains were eroded and the debris in the form of stones and gravel was carried down to the sea. These coarse gravels were deposited at the river mouths in great fan-like deposits, pushing simultaneously seawards and sidewards to eventually join up and form the Canterbury Plains. At the intersections of these deposits, smaller rivers such as the Ashley, Selwyn and Ashburton now flow. Gravel deposits reach depths of up to a kilometre, soil is only 20-25cm, mostly made up of loess (wind blown soil). The Canterbury Plains was covered by totara dominated forest 2000 years ago, then huge fires devastated many trees. After the arrival of the Maori, much of the remaining forest of the Canterbury Plains was burnt, probably to allow bracken, the source of fern root, to establish itself.

Braided rivers
One the most distinctive habitats are braided rivers, huge channels of gravel that carve right across the Canterbury Plains and the MacKenzie Country, swirling with dust when the nor’wester blows. Plants and particularly birds have managed to establish themselves quite successfully in these arid and dynamic areas - over thirty bird species have been identified as using braided rivers, notably of course the wrybill and the black stilt.

Banks Peninsula
Made up of the remants of two basaltic volcanoes, Lyttleton and Akaroa which became extinct about 5.5 million years ago. Until the recent geological past, this area was an island, but was joined to the mainland by the gradual eastward movement of the Canterbury Plains.

Truman Beach
The cliffs are sandstone with sea caves carved in at their bases. The beach is covered in rounded pebbles – all about the same size, but who sorted them so precisely? Particle size on beaches is determined by wave action. Turbulent conditions produce steep shingle beaches, which drain quickly and contain little organic matter, and are too harsh for living creatures. Smaller waves give moderately sloped sandy beaches whose smaller particles hold some water and often have shellfish buried beneath. Calm conditions create mud flats rich in organic matter (organic materials break down into small particles which settle out with fine mud particles) and good at holding water, where snails, crabs and mangroves can survive at the surface.

Flora

New Zealand's native biodiversity includes an estimated 3080 plants! Species introduced from outside New Zealand add to the overall biodiversity, bringing the total to around 6000 plants.

Beech Forest
Beech forests are the most widespread and successful forest type in New Zealand. They occur from almost Auckland to Southland - only Northland and Stewart Island are exempt from their advances. Unlike podocarps which rely on bird dispersal, beech seeds spread by wind so the forest expands more slowly but predictably. There are five beech species in New Zealand. The distribution of the southern beeches was a major piece of evidence supporting the concept of continental drift. Beech seeds do not survive in the ocean, are too heavy to spread by wind, and are not carried by birds, so could not have spread between continents. Therefore beech must have spread when the southern continents were joined together as Gondwanaland, 80 million years ago.

Beech forests show an interesting reproductive strategy: they don’t flower every year but instead they flower and seed prolifically every 3-5 years (usually) following a warm dry summer. In mast years they produce millions of tiny red flowers, and later nuts, which cover the forest floor. This irregular pattern is thought to provide protection from predation. If the nuts were produced every year they would provide a reliable food source for a large population of seed eaters e.g. mice, birds, which would consume most of the seeds. The irregular pattern means that seed eater populations cannot build up too high during the non-mast years, and in mast years hopefully the quantity of seeds produced exceeds the amount which can be eaten. Mast years affect the whole ecosystem: the populations of mice in the forests explode due to the abundant food supply providing abundant food for their predators, weasels and stoats, which also reproduce prolifically. Eventually the food runs out and the mice numbers decline, leaving a surplus of hungry mustelids. These turn to other prey, notably the eggs and chicks of native birds, many of which suffer disastrous losses following mast years.

Beech often has a sooty looking fungus growing on it’s trunk, which grows on the secretions excreted by a scale insect feeding on sap under the bark. You can see the tiny white ‘anal tube’ threads of the insect, and often spot the sweet-tasting drops dangling at the end. Honey-eaters like tui, bellbird and silvereye, enjoy this bounty, as do the bees, which gather the secretions and turn it into what we call ‘honey-dew’, which has itself turned into a useful export crop. Insects that live in the sooty fungus also provide a food source for the birds. You can smell the heady honey-dew scent in season, but unfortunately wasps as well as bees are attracted to it.

Red beech is a handsome tree and likes fertile lowland areas, and has the largest leaves and is spread from East Cape to Southland. It is the tallest of the beech species reaching up to 30m and an age of 400-500 years. It is named both for the colour of the timber and of the young trees in winter which have a reddish tinge. The southern beeches (Nothofagus), which also occur in Australia, New Caledonia and South America (and used to be in Antartica), are quite different from the northen hemispere beeches.

Hard beech is very similar to red, and is the most durable of the beeches and was put to uses from railway sleepers to weatherboards. The silica in the wood blunted saws and chisels so it was never popular with wood-turners.

Silver beech (Tawhai), Nothofagus menziesii, is the most widespread and generally likes drier or higher slopes. It has a parasitic fungi nicknamed ‘beech strawberry’, a cute orange honeycomb ball.

Black beech is similar to mountain beech, but the leaves are generally oval, and mountain beech grows at the highest altitudes and has the smallest leaves, which have a distinct pointy end or ‘peak’ to them.

Bushline
The bushline occurs where mean air temperature for the warmest month is approximately 10 degrees C. i.e it is limited by summer temperatures not winter. Above the bush line the warm weather does not last long enough for new growth to become tough enough to survive the next winter. Silver Beech forms the tree line where limestone present, mountain beech on the cold dry exposed ridges.

Alpine plants
These plants have to cope with extremely cold, windy and dry (when water is frozen) conditions. They generally don’t grow very large due to the limited resouces (energy) available, and growing close to the ground gives some protection from wind and cold. Generally they have small leaves as these are less easily chilled and dried out, and less likely to be damaged by wind and hail. Many are hairy as this prevent air movements over the leaf surface, and therefore protects from cold and dessication. The complexity of landform, underlying geology, slope and aspect, produce a wide variety of micro-climates which in turn affects the vegetation. Over half of New Zealand's 2400 native plants grow in Kahurangi National Park, including 67 species which are found nowhere else. 80% of New Zealand's alpine plants are here because the area escaped the worst of the ice age!

Hebes – a genus with many NZ species characterised by leaves in four rows. Alpine species tend to have smaller leaves.
Mt Cook lily is actually a buttercup (Ranunculus lyallii).
Mountain daisy (Celmisia spectabilis) is a large white daisy - the dried leaves can be smoked and have a beneficial affect on asthma.
Mountain Foxglove (Ourisia) is an asymmetric white flower with yellow middle.
The spaniard, speargrass or taramea (Aciphyll spp.) is memorable due to its needle sharp leaf-tips. There are 40 species, all but one in New Zealand, and most are alpine plants.
Snow totara is a prostrate shrub, an alpine version of the closely related totara tree, and has sweet red edible berries, good food for keas and people.
Snowberry has white flowers and white, pink or red fleshy fruits, also edible.

Tussocks
Tussocks grow very slowly - some plants may be centuries old. They flower every 2-3 years, after a warm summer, as they can’t store enough energy to flower every year. Tough pliable leaves can cope with being snow covered for months – bend rather than break.

Divaricating plants
A feature of New Zealand flora is the number of plants that have divaricating branches i.e. they branch at right angles producing a mass of interlaced stems and twigs, with the small leaves inside. There are around 60 New Zealand species from different families which do this, not common in other countries. This growth pattern may be due to climate – it is most common in dry beech forest and open areas exposed to b winds, extreme temperatures, and may provide a microclimate within the plant where leaves are protected from cold and dessication. The other possible cause is that this form evolved to protect the plant from browsing by moa, by hiding the leaves away inside the mass of twigs. The habit usually ceases if and when the plant reaches more than 3 metres in height, coincidently the maximum height at which the largest moa could feed. Moa were known to eat these plants, which occur in moa habitats – forest and forest margins. This question is still unresolved.

Kawakawa
Kawakawa (Macropiper excelsum) is easily identified from its attractive heart-shaped leaves, invariably nibbled with small holes — and therein lies a story. Though an inoffensive looking plant, kawakawa is one of the most potent plants in traditional Maori medicine, and modern chemical anaylsis supports much of this usage. Known also as the Pepper Tree, the Maori used the medicinal properties of the leaves and bark for treating cuts and stomach aches and a pulp from the leaves helped ease rheumatism. Chewing the leaves also helped to alleviate toothache. Both leaves and bark and fruit used as aphrodisiacs, having a stimulating effect on the body organs. It is related to kava. Knowledgeable New Zealand campers toss some of the leaves on their campfires, the acrid smoke repels mozzies and sandflies. Often the leaves were burnt near kumara crops because the acrid smoke discouraged most insect pests, but one insect, the brown looper caterpillar has built up an immunity to the toxins in the leaves and munches away contentedly. So much so that it is hard to find an unbitten kawakawa leaf.

Rangiora
Bushman's friend (Brachyglottis repanda), the soft underside of the leaf makes it good toilet paper if you are caught short in the bush. It is a small, bushy tree or tall shrub endemic to New Zealand. It grows to a height of 5 to 7 metres. It was also used as note paper in early days of New Zealand, and Maori used the large leaves for wrapping food for the hangi. The leaves are antiseptic and were also used to cover wounds and sores. Maori used the leaves as a type of chewing gum, but it has since been found to contain an unknown poison, so not recommended.

Flax
Harakeke (Phormium tenax and Phormium cookianum) is a distinctive coastal plant, preferring wettish ground, but will grow just about anywhere. Its familiar 3m leaves and stiff red-petalled stalk have become common sights in suburban gardens. Nectar feeders such as tui, bellbird and silvereye, love the sweet juice and act as pollinators for the plant. There are two species of native flax, but many varieties. Some types of flax were used for rope-making throughout the country by the Europeans, but the uses that the Maori put this plant to were wide-ranging and ingenious. They made rope, and used thinner fibres as a sort of universal ‘string’. Flax sandals called ‘parara’ were made for travelling, and ‘kawa’ was the name given for the flax pack-straps. The dry flax stalks were bundled together to make rafts or ‘mokihi’, and the broad flax leaves were entwined to make a base for making bread. The leaves could also be used for cooking food in.

Rainforest
The high species diversity characteristic of rainforest: trees include podocarps, rata and kamahi, nikau palm, tree ferns with numerous smaller plants, ferns, mosses and epiphytes. Larger trees may be covered with 20 or more other species.

Podocarps
Podocarps are a southern hemisphere family of trees, which dominated the forests 100 million years ago when the southern continents were joined as Gondwanaland. They are conifers i.e. have cones instead of flowers, and are more ancient than the flowering plants which are now the dominant type (e.g. beech). Podocarps do not have typical cones, but bear their seeds on a fleshy stalk or fruit, which is edible. Birds eat these fruits and aid in the dispersal of the seeds. The podocarps flourished more in New Zealand than anywhere else, and there are now 17 species. Of these five are the forest giants: rimu, miro, matai, totara and kahikatea, while the other 12 are smaller plants. The five giants grow to 30-50m high, often emerging above the forest canopy, and may live to 800 years old. They yield good durable timber and were logged extensively.

Rimu (red pine), Dacrydium cupressinum, is most easily distinguished by its drooping foliage and brown trunk. The timber is highly valued for beautiful furniture but it looks much better in a forest than in a house. Captain Cook used it to make a nutritious and tasty beer: rimu and manuka branches were boiled together for 3 hours, strained, molasses was added and boiled, then the liquid was cooled and yeast added to ferment it.

Miro, Prumnopitys ferruginea has grey hammered bark and red berries of which kereru (pigeon) may eat so many that they can hardly fly. The Maori used it medicinally – the oil from the berries to treat fever and the gum to stop bleeding of wounds, and as an insecticide.

Matai (black pine), Prumnopitys taxifolia, has foliage and bark similar to miro, but has purple berries eaten by kereru, kaka, and Maori. The juvenile form is divaricating. Sap tapped from the heart of matai was known as matai beer – a refreshing drink believed to aid recovery from tuberculosis.

Kahikatea (white pine), Dacrycarpus dacrydioides, is the tallest native tree, reaching 60m and may live more than 500 years. It is one of the podocarps, in fact the most ancient one in NZ: its pollen from 160 million years ago has been found so it lived with the dinosaurs. It lives in swampy lowlands and on the flood plains of rivers. In NZs early days, it was valued for its pale, odourless, resin free timber which was ideal for making boxes for exporting butter and cheese without them being tainted.

Totara, Podocarpus totara, was a favourite tree of the Maori who would choose one of the biggest to make a waka (war canoe) large enough to hold 100 warriors from a single trunk. They also used totara for building and carving, harvested the berries, and boiled the bark to make an extract for treating fever, skin conditions and piles. The timber is resistant to rot and Europeans used it for fence posts, door steps, window frames and telephone poles.

Epiphytes
Epiphytes and vines are both characteristic of rainforests. Both gain access to the canopy and therefore to sunshine by growing on other plants, instead of growing their own trunk. Vines germinate on the ground and climb up trees, e.g. climbing rata (Metrosiderous robusta), supplejack (Rhipogonum scandens). Epiphytes germinate on their host plant (epiphyte means “on plant”) and must catch and hold water and organic debris as they have no access to soil. (These are not parasites as they take nothing from the host but just get a place to live.) e.g. mosses, lichens, ferns, astelias (perching lilies), orchids, broadleaf. Kamahi (a broadleaf tree, Weinmannia racemosa) often begins as an epiphyte on a tree fern, but sends roots downwards as it grows into a free-standing tree.

Rata
Ratas (Metrosideros robusta (Northern Rata), M. umbellata (Southern Rata)) may be trees or vines depending on the species, best known for covering hillsides with a brilliant display of red flowers around Christmas. Northern rata (North Island and south to Westland) begins life as an epiphyte, on a large tree like rimu, and grows roots down to the ground, which thicken and become a trunk, eventually replacing the host as it grows into a huge tree. Southern rata (both islands except Northland) germinates on the ground and grows as a shapely tree (to 15m). Both have brilliant red flowers and are an important source of nectar for tui and bellbird. Several species of climbing ratas grow as vines, climbing up host trees. They are distinguished by their flowers (red, orange, or white) and leaf size and shape. Pohutakawa is in same genus (Metrosideros) which means iron wood.

Supplejack
A tangle of dark twining stems providing a trap for trampers who venture off the track. As they grow, they spiral anticlockwise, and coil around any stems or branches they encounter, thus making their way up into the canopy. The flesh of the red berries is edible but rather bland, and there are often not many due to the 1-2 large seeds within. The tender young shoots make a refreshing snack and are said to cure scabies (Maori medicine).

Easter orchid
One of the epiphytic perching orchids, Earina autumnalis, has a spray of tiny cream flowers and distinctive sweet, generally pleasant scent which is often compared to vanilla in nature. They are often smelled before they are seen.

Nikau palm
The only palm tree found on the mainland of New Zealand, Rhopalostylis sapida, and a reminder of this country’s more tropical neighbours. It is the southernmost member of the palm family. Usually about 10m tall, with a tuft of leaves reminiscent of a feather duster, the name Nikau means 'many leaves on the same stalk'. The fruits are enjoyed by the native birds, particularly the wood pigeon. The immature flower is edible, cooked and eaten like cauliflower. The green berries are also good eating, but not so good when ripe. The heart of the developing leaves is tasty too but taking it kills the plant – they are known as millionaires salad. The Maori wrapped food in nikau leaves before cooking it, and the large leaves were also used for baskets, floor huts and thatching for huts.

Kiekie
Freycinetia banksii, a scrambling climber forming a mass of sword-like leaves over tree trunks. Starting as a small shrub it rapidly develops a climbing mode, covering fallen trees, rocks and other low to medium level features of the bush. The leaves were used by the Maori for mats and baskets, and the extracted fibre for making rain capes and fish traps. The fruit is said to be the finest fruit in the forest. The large (70-150 mm) green fruits are slightly tinged with yellow or pink when fully ripe, and also a favourite of rats and mice.

Manuka
Leptospermum scoparium, one of the most wide-spread tree-shrubs in New Zealand, and for long time, one of the most disliked. Settlers battled hard to clear their land, and manuka was regarded as an invasive shrub that undid all their hard work. Times have changed and the list of beneficial qualities of manuka now far outweigh its disadvantage. Manuka often acts as a ground cover for other native seedlings, breaking in the exposed ground. It has sweet-smelling flowers that produced nectar and make a fine honey. The medicinal and antiseptic qualities of manuka oil are being steadily exploited and already there is a line of pharmaceutical creams and ointments. And the manuka burns with such a sweet fierceness that people are starting to plant manuka as future firewood lots. And you can always try throwing a handful of fresh leaves into a boiling billy and drinking the ‘tea’, Captain Cook did — hence the name ‘tea tree’. Some parakeets chew the plant oils and mix it with preen gland oil to apply to their feathers.

Cabbage tree
A distinctive plant which was highly prized by the Maori for its many uses. The roots, stem and leaf buds provided food, drink and chewing gum, with the cooked shoots being eaten as a vegetable (with a high carbohydrate content, and said to taste like artichoke) hence the name cabbage tree. The leaves were used to make kete, ropes, sandals, capes, snares and thatching. The plant provided medicines for colic, dysentary and diarrhea. The trees were grown as signposts: track markers through swamps, river crossings, burial grounds. After the birth of a baby, the placenta was buried under a special cabbage tree, symbolically linking the people to the land.

Cushion plants
Grow in closely packed form which traps warm air and moisture, and protects them from wind and movements of snow down a slope. They have wiry, tough branches, with densely packed leaves at the tip to reduce wind battering, fleshy or hairy leaves that trap moisture and slow evaporation, and an internal self-mulching network of dead leaves and branches. Vegetable Sheep is a curious cushion plant earns it’s name from some of the larger specimens, that from a distance an exhausted musterer mistook for the woolly humps of his stray sheep. Here the vegetable sheep are quite small, and survive amongst a number of different cushion plants.

Sphagnum Moss
An interesting example of a plant, once formally thought useless, and now so highly valued that there have been some instances of ‘sphagnum poachers’! The qualities that make sphagnum so valuable is its ability to absorb up to 20 times it’s own weight of water. This makes it ideal as a potting medium, particularly for the Japanese orchid market, and exports to Japan total 700 tonnes a year or more - ten million dollars at least. Because sphagnum moss is also sterile, and harbours no bacteria, it was partly used for bandages in the First World War, and has now found a modern use in sanitary pads. Sphagnum has no root system, and can be easily picked. There are a number of sphagnum species, and texture and colour can vary widely. Also has an important role in nature, by absorbing rain water it slows the runoff and reduces damage by flooding and erosion.

Ferns
NZ has a large diversity of ferns, primitive plants which generally prefer damp environments. Ferns have a two stage lifestyle: they produce spores on the backs or edges of the leaves, which germinate on the ground producing heart-shaped prothalli (very small). These produce eggs and sperm, which after fertilization, grow into a new fern plant. Eg, filmy ferns, are only one cell layer thick, beautiful in the sunlight. Eg, crown fern (piupiu, Blechmun discolor).

Tautuku Forest
Tautuku Forest Reserve is 550 hectares of virgin rain forest, and shows the high species diversity characteristic of rain forest: trees include podocarps, silver beech, rata and kamahi, with numerous smaller plants, ferns, mosses and epiphytes. The forest is separated from the long golden beach by a narrow band of scrub and sand dunes – with the native pingao (orange and green leaves) and intoduced invader marram grass.

Hieracium
( hawkweed) A ground-hugging plant, that fills up spaces unoccupied by tussocks or grass, and is unpalatable to stock. It is a vigorous grower and has spread widely in the Mackenzie area, usually in a partnership with the rabbits, which eat the grass and leave the area free for Hieracium to invade. It has now become a serious pest. Curiously, Hieracium seed has been exported to Germany, for use as a plant along the banks of the autobahns.

Mistletoe
Like the pohutukawa and rata, the mistletoe (pirita) is a ‘Christmas’ plant, flowering in a red outburst of colour amongst the drabber silver beech which is its common host. The mistletoe is a hemi-parasite (a part parasite), as it photosynthesises it’s own ‘food’, but extracts minerals and water from the beech tree, as well as grabbing a vantage point. Unfortunately, because the possum seems to be particularly fond of the mistletoe, this attractive plant will be an increasingly rare sight in the future. In season there can be an amazing display of mistletoe up the Ohau valley.

Fauna

Wasps
New Zealand has several types of wasps. It’s own native species go relatively unnoticed, but the introduced German Wasp and Common Wasp, are much more aggressive. These wasps are ferocious and highly competitive invertebrates, attacking almost any insect, chicks in nests, and of course, humans. In some areas, where the honey dew in the beech forest is a major attraction, the wasps once reached almost plague proportions with an enormous adverse effect on the native bird and insect populations, effects that are not yet easily measured or understood. The Common Wasp queen usually hibernates in winter, then lays worker eggs, which feed her as she lays new queen eggs and drone eggs. These hatch and mate and the new queens form nests of their own. A wasp nest is usually about 400-500 wasps in number. Cold conditions usually kill off all except the queen, though in warmer areas, the nest survives and can grow to an abnormal size. Humans have introduced natural parasites that live on wasp nests, but this process is slow.

Powelliphanta
Giant carnivorous land snails, feed on worms, slugs and smaller snails. They are ancient organisms, originating 235 million years ago. Isolated populations have evolved into numerous species, producing a variety of beautiful forms. They can live for 20 years if not eaten by possums or wekas.

Glow worms
These have the most efficient method of producing light known to man, something like 99% energy transfer. Glow-worms are the carnivorous larvae of a gnat, transparent, living in a small tube from which are hung sticky, silky threads which trap their prey - which is mainly midges. The midges are attracted to the luminescence, which has been calculated at one nanowatt (one thousandth of a millionth of a watt). The actual cause of the ‘glow’ is the oxidisation of a chemical called luciferin, present in the glow-worm. The male shines with a blue-green light, the female is more reddish. The hungrier they are the more they glow! Before emerging as a flying gnat, the female larvae pulls in the loose threads (to avoid trapping herself when she exits) and suspended from one single thread emits a b pulsing light which attracts the males. She is immediately mated on exit and has a one to three days existence to lay her eggs to continue the cycle. Male sometimes flies into the web of larvae in search of female. Not total loss as energy transferred to larvae.

Weta
49 species of cave wetas endemic to NZ, distinguished from other wetas by their exceptionally long antennae, small body, and long prickly legs. Known to eat decaying vegatable matter, and live plant material, or they are cannibalistic. Live in caves or under logs and often come out at night to browse on the forest floor. Wetas are insects found only in NZ and are ancient creatures, virtually unchanged since 190 mya. They belong to the same order as crickets and grasshoppers, and like them having distinctive large back legs. However, like several other NZ species, the weta has become large and flightless, and it has adopted the lifestyle of a nocturnal rodent. The largest wetas are the giant wetas, which are among the largest insects in the world. The most common are the tree wetas, seen in gardens, stacks of firewood, gumboots, and any damp dark places.

Long Tailed Bats
(Pekapeka) have been the subject of an extensive and ongoing study in the Eglinton and Hollyford valleys. These bats are born fliers, much more so than their rarer cousins, the short-tailed bats. The long-tails have a body about the size of a human thumb, weigh about 7-12 grams, with a wingspan up to 20 centimetres long. Their age is still something of a mystery, but they mostly feed on insects, and live both in small colonies and in individual roosts, usually preferring old established trees. They are most active in the warmer summer months, particularly when insects abound. At cold temperatures they stay inactive (torpid), though whether they actually hibernate is not really known. The long-tailed bat is the commoner of the two bat species, and has been reported from a wide number of sites around New Zealand, from Northland to Stewart Island. It seems to be suffering a decline, perhaps through predation or habitat loss, and in some places where it has been recorded regularly before, such as Banks Peninsula, there have been no recent sightings at all. The best time to see the long-tails is at dusk, and Lake Gunn is a place where they are frequently seen, flitting like nervous, turbo-propelled ‘swallows’, except there are no swallows in the Eglinton or Hollyford Valleys. So if you’ve seen a ‘swallow’, you’ve seen a bat.

Skinks
If you see a flash of black and gold colour on a rock then you might have seen a skink. The Otago skink and grand skink (both measuring about 30 cm) inhabit the rock crevices in the schist outcrops and tors, and both are jet black with yellow and gold markings, which acts as an excellent camouflage in the lichen covered rocks. Grand skinks are more active and alert than the more sedate Otago skink, which likes to bask in family groups within easy reach of a safe crevice.

Black Ringlet
The black ringlet butterfly has dark brown to satiny black wings with small white dots, and it lays it’s eggs on the underside of rocks rather than on vegetation, perhaps because the warmth from the rocks speeds up the development of the eggs. It thrives in harsh alpine environments, and can survive on the bare glacial moraine of a great glacier like the Tasman.

Whitebait
Whitebait are the juveniles of 5 species of freshwater fish called galaxiids. The most common is inanga – these only live for one year and spend half their time at sea, half in rivers. The eggs are laid and fertilised on plants in damp areas beside rivers, when these plants are flooded by high spring tides. The eggs develop there until the next spring tide when the larvae hatch and swim down to the sea where they live for 6 months. Then they return as whitebait, swimming up rivers in large numbers, at which time people fish for them using large nets. Those that elude the nets live up river until spawning time, when as adults they swim down until they meet the high spring tide, then swim into the flooded riverside vegetation to lay their eggs. Another species, the giant kokopu, can live for 20 years. The West Coast has most whitebait as it has the least modified rivers and estuaries. They are threatened by habitat loss, overfishing, and predation by introduced trout. The crucial connection of estuaries and wetlands to whitebait breeding areas is only now generally appreciated, and the days when early travellers reported their dogs lapping out the whitebait have gone. Destruction of the habitat by drainage and irrigation have ironically seen whitebait become a treasured resource, where the high excitement of the first whitebait catches of the season are matched by the high prices in town. To think once it was dumped as fertiliser!

Birds

Rifleman
(titipounamu = ‘iti’ small, ‘pounamu’ greenstone) ‘little piece of greenstone’ might be one translation. It is one of two New Zealand wrens. The name rifleman also refers to its colour – military uniform. They are insect eaters, foraging on tree trunks and picking insects from the surface or from cracks. The male is the smallest bird in New Zealand, at only 6 grams. He feeds the female while courting and helps with incubation of the egg, which is laid in a nest in a hole or crevive in a tree. The female lays an egg mass (3-5 eggs) which weighs 84% of her body weight. The high pitched ‘zip zip’ of riflemen is above the hearing range of older people.

Rock Wrens
Rock wren, NZ’s only completely alpine bird which lives above the bushline all year round and lives under the snow in the winter (may see one at Mt. Cook). An alpine bird seen in the South Island mountains, identified by its big feet for hopping around on rocks, and bobbing movement. Is a weak flier, feeding on insects and fruit, and hiding in rock crevices to survive winter at high altitude. Stephens Island wren (Cook Strait) is an extinct relative. It was flightless and was observed by the lighthouse keeper whose cat kept bringing in small corpses. The keeper sent a few samples to scientists, but by the time the scientists realised the bird was unique they had all been killed by the efficient cat! The Stephens Island wren scurried through undergrowth and occupied the niche normally filled by mice, and this mammal-bird switch is common throughout NZ where bats are the only two native mammals. For instance the moa occupied the browsing niche normally taken by larger herbivores like deer.

Blue Ducks
One of four species of torrent duck in the world, they live in fast flowing mountain and bush rivers, and have b webbed feet which allow them to maneuver in powerful river currents. They feed on insect larvae scraped from the surface of stones


Marine Mammals

Fur seal
New Zealand fur seal is only found in New Zealand waters and off the south coast of Australia. The seals arrive for giving birth in November and December, and by March the numbers of pups are at their peak. Groups of them get together to play games that look for all the world like ‘king of the castle’ and ‘tag’. Female seals are sexually mature at 3-4 years, males at 6-7, though the latter rarely become active till 9 or 10 years old when they are strong enough to compete against other bulls. Females invest more energy in male pups as it is more important for them to be big and strong to win a harem. Females give birth then mate with males a few weeks later and colonies are at sites where there are lots of rock pools and the pups are safe from sharks. Females and pups stay close to the breeding place most of the year whilst solo males move away, frequently hauling ashore all around New Zealand’s coastline. Seals can travel for hundred of kilometres but their migration habits are still not widely understood. Seals dive to 20m and the principal diet of fur seals are squid, octopus, lantern fish and barracuda, with most feeding done at night. Seals often get caught in hoki nets and then get shot by fisherman.

Hector's dolphin
One of the smallest and rarest marine dolphins in the world, they are found only in NZs inshore waters (mostly around South Island, particularly Te Wae Wae Bay, West Coast and Banks Peninsula), and there are only 3000-4000 of them. They are about four and a half feet long (1.4 m) and have attractive black and white patterning, and are easily distinguised from other dolphins by the rounded dorsal fin. They feed close to shore, catching fish, squid and crabs. They live to about 20 years old, females maturing at age 7-9 and having one calf every 2-3 years. The species is declining due to being caught in fishing nets nets (224 in 4 years around Banks Peninsula) which is too much for the low reproductive rate to compensate for. A marine mammal sanctuary has now been put in place around the Banks peninsula forbidding set netting during the summer months when the dolphins are inshore breeding. The Porpoise Bay population is unusual in that it is the only place these dolphins live permanently so close to shore. There are about 20 of them and they breed and feed here, and are often seen surfing. We want to look after this population which means: do not feed or touch them, do not approach them or try to swim with them. If they choose to swim with us that is okay. It is illegal to disturb or harrass native wildlife.

Hookers Sea Lion
The name sea lion is a tribute to the light ‘mane’ on the bull sea lions. The bulls, which can weigh up to 450 kilograms, can when disturbed get up on their front flippers and ‘strut their stuff’ with loud aggressive snorts, their pink mouths contrasting with their shiny black-brown bodies. Female sea-lions weigh only 180 kilograms, are paler in colour and less aggressive. The main colonies for the sea-lions are in the sub-antarctic Auckland islands (@ 15,000 in the main breeding areas), but they are slowly returning in greater numbers to the Catlins coast and Otago Peninsula. There is some early evidence that they may be starting to breed back on the mainland again, after being slaughtered by Maori and European sealers. Pups are born in December, and the females mate again soon after, delaying implantation so that the pups are born at the warmest time of year. They come ashore on sandy beaches, sometimes going right up into sand dunes. They feed on squid, fish, krill, octopus and crabs, and sometimes sea birds, penguins and seal pups. Sealion pups may be eaten by sharks, orcas, leopard seals, and they sometimes drown. Squid-trawling nets pose a threat to sea lions so a kill quota has been introduced: the squid fishery closes for the season as soon as 63 sealions (or 32 females) are killed. They can dive to 400 m depth but the average dive is 200m for 12 min. True seals (sea lions are eared-seals) stay down much longer - eg elephant or Crab-eater. Humans exchange 10% of lung air with each breath - sealions 40%. Blood volume is relatively greater than us, 15% of body mass compare with only 7.5% for humans, therefore storing more oxygen in haemoglobin and have more myoglobin. Heart rate normally (resting) 60-90 beats per minute, but while diving slows down to 10 beats per minute - blood shut off from extremities and directed to vital organs. Males can be aggressive in the breeding season (Dec-Feb) and should not be approached closer than 30 m, nor should their escape route to the sea be blocked.

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