New Zealand

C

Rivers and Lakes

Lake Taupo is the largest lake in New Zealand. It covers an area of 606 sq km (234 sq mi) in the central volcanic plateau of the North Island. The lake occupies the crater of an extinct volcano and reaches a depth of 162 m (531 ft). Its outlet is the north-flowing Waikato River, the country’s longest river. The Waikato flows to the northwest for a distance of 425 km (264 mi) and empties into the Tasman Sea. It has been dammed in several places for hydroelectricity generation, and its drainage basin is one of the country’s most fertile agricultural areas.

The largest lake of the South Island is Te Anau, covering an area of 344 sq km (133 sq mi). Te Anau and many other South Island lakes are glacially carved troughs on the eastern flank of the Southern Alps. Several of these lakes are part of the upper Waitaki River hydroelectric system. Water from Lake Manapouri, south of Te Anau, is also harnessed for hydroelectricity.

Most of the rivers of the South Island originate in the pristine glacial lakes of the Southern Alps and flow generally southeastward to empty into the Pacific Ocean. The Clutha River, the largest river of the island at a length of 336 km (209 mi), originates at Lake Wanaka and is fed by several tributaries as it flows southward across Otago Province. The Clutha River discharges the largest volume of water of any river in New Zealand and has been dammed in a number of places for hydroelectricity generation. North of the Clutha, the Waitaki River crosses the Canterbury Plains in central South Island. Its huge catchment area is one of the most valuable hydroelectric power resources in the country. It and other rivers to the north formed the Canterbury Plains by redistributing vast quantities of gravel from the Southern Alps. They occupy wide gravel beds and are navigable only by jetboat, a flat-bottomed boat that skims the surface of shallow waters. The rivers provide a source of irrigation water for the crops and grasslands of the agricultural region.

D

Plant and Animal Life

The long geographical isolation of New Zealand had a profound effect on its plant and animal life. When New Zealand broke away from the last part of Gondwanaland around 82 million years ago, it carried with it plants and animals from the Age of Dinosaurs—most famously primitive tree ferns and the tuatara, a lizardlike reptile that emerged more than 200 million years ago. However, the fossil record on the islands is relatively sparse and is particularly fragmentary for land animals. Only a few bones show that dinosaurs and flying reptiles once lived on New Zealand. Better known are remains of giant extinct marine reptiles from the Mesozoic Era such as mosasaurs and plesiosaurs. Fossils of early whales that lived during the following Cenozoic Era have also been recovered.

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Scientists once thought that snakes and nonflying mammals had not reached New Zealand before it broke away from the rest of Gondwanaland. However, recently discovered fossils show that snakes, crocodiles, and primitive nonflying mammals survived on New Zealand as late as 16 million years ago during the Miocene Epoch. Later climate change apparently killed off these three groups, leaving birds as the dominant land animals and bats as the only indigenous nonmarine mammals. The tuatara survives nowhere else in the world but on a few islands off the coast of New Zealand.

The plant life of New Zealand includes about 1,500 indigenous species found nowhere else in the world, including the golden kowhai and the scarlet pohutukawa. Also notable among the native plants are tree ferns and primitive araucarian pines, both holdovers from the Age of Dinosaurs. The number of introduced plant species now rivals the number of indigenous species, however. Some introduced species, such as the furze (gorse), a thorny evergreen shrub, have acclimated so well in New Zealand that they have become a menace, spreading quickly and displacing indigenous vegetation. Most of the indigenous trees and shrubs of New Zealand are evergreen, including the kauri, rimu, kahikatea, and totara. Original mixed-evergreen forests remain in only the remotest areas of the North Island and in the Southern Alps. Beech trees predominate on the western slopes of the Southern Alps. Radiata pine, a fast-growing timber tree imported from California, is found in large reforestation plantations on the central volcanic plateau of the North Island. Sown grasses predominate in many lowland plains and on the eastern flanks of the Southern Alps up to an elevation of about 1,500 m (5,000 ft).

Isolation from other landmasses allowed birds, bats, and small reptiles to flourish in the absence of predatory mammals. Without such ground predators, many bird species in New Zealand became flightless or semi-flightless, often nesting on the ground. Most famous of the flightless birds were the giant ostrichlike moas, which grew as tall as 4 m (13 ft) and weighed up to 250 kg (550 lb). The largest flying bird and top predator was the extinct giant Haast’s eagle, which had a 3-m (10-ft) wingspan and 7.5-cm (3-in) claws. It likely preyed on moas. Many of these birds, including the moas and giant eagles, became extinct after people colonized the islands. Some species such as the moa were hunted to extinction, while others suffered from the destruction of habitat and the introduction of foreign predators, such as rats and stoats. Some flightless birds have survived, however, including the kiwi, a nocturnal bird that is the national emblem; the kakapo, the world’s largest parrot; and the weka and the takahe, both large species of rail. However, many of the remaining indigenous species are in danger of becoming extinct. Some are officially protected as endangered species, and the government has designated nature reserves for the preservation of natural habitat.

Native songbirds such as the bellbird and tui also contribute to the country’s large population of wild birds. The sparrow, blackbird, thrush, skylark, magpie, and myna are well-acclimatized imported species. New Zealand also abounds in a great variety of seabirds, such as the albatross, and numerous migratory birds. Six species of penguins inhabit the islands and rugged coastlines around New Zealand, including the yellow-eyed penguin, found only in New Zealand, and the blue penguin, the smallest penguin in the world.

Many marine mammals populate the waters around New Zealand. Among the species of dolphins, whales, and seals are Hector’s dolphin and the New Zealand sea lion, which are found nowhere else. The humpback whale and the southern right whale were once numerous in New Zealand’s offshore waters, but these species never recovered from the intensive commercial whaling that took place in the 19th century.

The only surviving indigenous land mammals in New Zealand are bats. All other wild land mammals now in New Zealand arrived with humans. The Maori brought rats and dogs with them when they reached the islands. The rats were originally used as food but escaped into the wild. The Maori dog became extinct after Europeans arrived. The rest of the modern wild animals are descended from imported species brought by Europeans in the 18th and 19th centuries: deer, rabbits, goats, pigs, weasels, ferrets, and opossums. The populations of some introduced mammals, such as rabbits and the Australian opossum, have reached plague proportions. Feral cats are a threat to native birds.

In addition to the tuatara, the other reptiles native to New Zealand are small lizards (geckos and skinks), and turtles and tortoises. No snakes now inhabit the islands and special care is taken to prevent snakes from being accidentally introduced in cargo from Australia and other regions. A few native species of frogs also survive.

Unique to the islands are the cricketlike wetas, giant insects that play an ecological role similar to that of small rodents elsewhere. Venomous insects are rare but the introduced German yellow jacket and English wasp have become serious pests. The bumblebee was brought to New Zealand to pollinate imported clover.

The rivers and lakes of New Zealand have a variety of fish, including whitebait, eel, and freshwater crustaceans, particularly crayfish. Trout and salmon are imported species. The surrounding ocean waters are the habitat of many species, including the snapper, flounder, blue cod, hapuku, tarakihi, swordfish, and shark, as well as edible shellfish such as the oyster, mussel, paua (abalone), and toheroa. The giant squid appears to be fairly abundant in the deep waters—more than 100 specimens have been caught off the coast of South Island in recent decades.

E

Natural Resources

Land is one of the country’s most valuable resources. Much of the soil is not naturally fertile, however, and has to be supplemented with fertilizers for crop cultivation. More than half of the land area is either cropland or pastureland. Most of the arable land is found on the east coasts of both islands, in particular the Canterbury Plains. Pastures for livestock grazing dominate in north-central and western North Island and southern South Island.

About 31 percent of the land area is forested. The country has 6.4 million hectares (15.8 million acres) of old-growth forest, much of which is designated for preservation. In addition, some forests are plantations of imported species such as the radiata pine. The western Southern Alps of the South Island constitute the largest forested area of the country and include extensive areas of native forest. The North Island has native forest mainly in more remote areas, notably around Mount Taranaki and in isolated pockets of Northland.

In 2008 the government of New Zealand signed over huge tracts of forest land to the Maori to settle grievances stemming from past violations of treaties with the Maori. The settlement involved 176,000 hectares (435,000 acres) of forest in the central part of North Island. The area mostly consists of commercial pine tree plantations. Seven Maori tribes collectively own and manage the land under the terms of the agreement.

New Zealand rivers and lakes are an important natural resource as the source of hydroelectricity. Mineral resources are limited, with some reserves of coal, gold, iron ore, and limestone. Significant stocks of natural gas and less plentiful reserves of oil are located both offshore and in the western region of the North Island.

F

Climate

New Zealand’s location in the Southern Hemisphere, or south of the equator, means that its seasons are opposite to those in the Northern Hemisphere. The warmest months of summer are January and February and the coldest months of winter are June and July. New Zealand is located in the Southern Temperate Zone, south of the tropics. It has a mild climate with four seasons. Inland areas have cooler winters and warmer summers than coastal areas, where the moderating influence of the ocean creates a more temperate climate.

Temperatures tend to be warmer in the north than in the south; the warmest area is in the extreme northern end of the North Island, and the coldest area is on the southwestern slopes of the Southern Alps. In most of the country, however, there are only minimal climatic differences between north and south. Average low winter temperatures range from 2°C (35°F) in Christchurch, on the South Island’s central east coast, to 8°C (46°F) in Auckland, in the northwest of the North Island. Average high summer temperatures are 23°C (73°F) in Auckland and 21°C (70°F) in Christchurch.

New Zealand is located in the “Roaring Forties” wind belt, an area between latitudes 40° and 50° south where westerly winds sweep across the southern oceans. The prevailing westerly winds bring moisture from the ocean, resulting in heavy rainfall on the western coasts, especially on the South Island. The main divide of the Southern Alps receives the most precipitation in the country. The mountains form a natural barrier to weather patterns from the west; in the eastern rain shadow of the mountains, the westerly winds become warm, dry, and gusty. The east coasts are therefore much drier than the west coasts, and eastern areas of the South Island have some of New Zealand’s sunniest, driest weather. Average annual rainfall in Christchurch is about 638 mm (25 in), compared to 2,906 mm (114 in) in Hokitika, on the west coast. Auckland receives 1,247 mm (49 in) of rain annually.

Although the westerly winds prevail, the eastern part of the country is open to frequent southerlies, wind currents drawing cold air up from the Antarctic. Usually they bring rain, a sharp fall in temperature, and in winter, snow in the mountains. The northernmost extension of the North Island is subject to the tail end of tropical weather systems from the Pacific, and temperatures there are warm year-round, in most places never reaching the freezing point.

G

Environmental Issues

New Zealand has a reputation as “clean and green” because of its relatively small population and unspoiled alpine scenery. However, the country faces real environmental issues. Industrial and agricultural discharges into waterways, notably the Waikato River, have led to water pollution in some areas. Air pollution from motor-vehicle and industrial emissions is a concern in the large cities, such as Auckland. In addition, widespread clearing of the original mixed-evergreen forests—both for timber and to create more agricultural land—has led to loss of wildlife habitat. The practice also led to severe soil erosion, a problem the government has attempted to solve through reforestation programs. However, targeted reforestation areas have been replanted with fast-growing nonindigenous species.

New Zealanders have pioneered conservation efforts, clearing offshore islands of rats and other predators to help native birds survive. New Zealanders also have a tradition of environmental activism. In the 1980s grass-roots opposition to the construction of new hydroelectric power stations led the government to suspend plans for future projects. New Zealand relies heavily on hydroelectric power, which is generally regarded as clean energy. Many New Zealanders opposed the construction of new dams, however, because they alter the natural flow of rivers and are environmentally disruptive. Controversy over the building of new dams was an important factor in the creation of a new tier of regional government in 1989 to help implement resource-management provisions designed to foster long-term sustainability. The antinuclear lobby is also a potent force in New Zealand. There are no nuclear reactors in the country, and nuclear-armed or nuclear-powered vessels are not allowed in the ports.

The government-managed national parks program was significantly reorganized and expanded in 1987. Nearly one-quarter of the country’s land area is protected in government-designated national parks and reserves, including some of the country’s wetlands, mangrove swamps, coastal areas, and native forest. New Zealand works with the World Heritage Fund to preserve the World Heritage Site of Te Wahipounamu. This internationally designated preservation area includes several locations in the Southern Alps, including some areas of indigenous forests and two alpine national parks, as well as the coastal fjords. In addition, some areas have been designated for the protection of wildlife, including the Royal Albatross Sanctuary on the southern coast of the South Island, the world’s largest mainland breeding ground for the royal albatross.

New Zealand is actively engaged in helping to preserve the fragile marine habitats and ecosystems of the South Pacific Ocean. The country has ratified a number of international environmental agreements on topics such as biodiversity, marine dumping, and whaling.