Biodiversity of New Zealand - AbsoluteAstronomy.com

Biodiversity

Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...

of New Zealand, a large Pacific archipelago

Archipelago

An archipelago , sometimes called an island group, is a chain or cluster of islands. The word archipelago is derived from the Greek ἄρχι- – arkhi- and πέλαγος – pélagos through the Italian arcipelago...

, is one of the most unusual on Earth, due to its long isolation from other continent

Continent

A continent is one of several very large landmasses on Earth. They are generally identified by convention rather than any strict criteria, with seven regions commonly regarded as continents—they are : Asia, Africa, North America, South America, Antarctica, Europe, and Australia.Plate tectonics is...

al landmasses. Its affinities are derived from Gondwana

Gondwana

In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...

, from which it separated

Plate tectonics

Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...

82 million years (Ma) ago, New Caledonia

Biodiversity of New Caledonia

The Biodiversity of New Caledonia is considered to be one of the most important in the world. New Caledonia, a large south Pacific island group about 1,200 km east of Australia, supports high levels of endemism, with many unique plants, insects, reptiles and birds...

and Lord Howe Island

Lord Howe Island

Lord Howe Island is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, directly east of mainland Port Macquarie, and about from Norfolk Island. The island is about 11 km long and between 2.8 km and 0.6 km wide with an area of...

, both of which are part of the same continental plate as New Zealand, and Australia. More recently a component has been introduced by humans. New Zealand's pre-human biodiversity exhibited high levels of endemism, both in its flora

Flora

Flora is the plant life occurring in a particular region or time, generally the naturally occurring or indigenous—native plant life. The corresponding term for animals is fauna.-Etymology:...

and fauna

Fauna

Fauna or faunæ is all of the animal life of any particular region or time. The corresponding term for plants is flora.Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess shale fauna"...

. Prior to 65 Ma ago, the fauna included dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s, pterosaur

Pterosaur

Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...

s and marine reptiles such as mosasaur

Mosasaur

Mosasaurs are large extinct marine lizards. The first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764...

s, elasmosaurs and plesiosaur

Plesiosaur

Plesiosauroidea is an extinct clade of carnivorous plesiosaur marine reptiles. Plesiosauroids, are known from the Jurassic and Cretaceous Periods...

s. The range of ancient fauna is not well known, but at least one species of non-flying terrestrial mammal

Mammal

Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

existed in New Zealand around 19 Ma ago. For at least several Ma before the arrival of the human and its commensal

Commensalism

In ecology, commensalism is a class of relationship between two organisms where one organism benefits but the other is neutral...

species, the islands had no terrestrial mammals except for bat

Bat

Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...

s and seal

Pinniped

Pinnipeds or fin-footed mammals are a widely distributed and diverse group of semiaquatic marine mammals comprising the families Odobenidae , Otariidae , and Phocidae .-Overview: Pinnipeds are typically sleek-bodied and barrel-shaped...

s, the main component of the terrestrial fauna being insects and birds. Its flora is dominated by Gondwanan plants, comprising historically of forests, most famously the giant kauri (Agathis australis
Agathis australis
Agathis australis, commonly known as the kauri, is a coniferous tree found north of 38°S in the northern districts of New Zealand's North Island. It is the largest but not tallest species of tree in New Zealand, standing up to 50 m tall in the emergent layer above the forest's main canopy. The...

). New Zealand has developed a national Biodiversity Action Plan

Biodiversity Action Plan

A Biodiversity Action Plan is an internationally recognized program addressing threatened species and habitats and is designed to protect and restore biological systems. The original impetus for these plans derives from the 1992 Convention on Biological Diversity...

to address conservation of considerable numbers of threatened flora and fauna within New Zealand.

Evolution

The break-up of the supercontinent

Supercontinent

In geology, a supercontinent is a landmass comprising more than one continental core, or craton. The assembly of cratons and accreted terranes that form Eurasia qualifies as a supercontinent today.-History:...

of Gondwana

Gondwana

left the resulting continents and microcontinents with shared biological affinities. Zealandia

Zealandia (continent)

Zealandia , also known as Tasmantis or the New Zealand continent, is a nearly submerged continental fragment that sank after breaking away from Australia 60–85 million years ago, having separated from Antarctica between 85 and 130 million years ago...

(the continental crust from which New Zealand and New Caledonia later developed) began to move away from Antarctic

Antarctic

The Antarctic is the region around the Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica and the ice shelves, waters and island territories in the Southern Ocean situated south of the Antarctic Convergence...

Gondwana 85 Ma ago, the break being complete by 65 Ma ago. It has been moving northwards since then, changing both in relief and climate

Climate

Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...

. About 23 million years ago New Zealand was mostly underwater. One estimate suggests just 18% of the present surface area remained above the water. However geological evidence does not rule out the possibility that it was entirely submerged, or at least restricted to small islands. Today about 93% of the Zealandian continent remains below the sea. Several elements of Gondwana biota are present in New Zealand today: predominantly plants, such as the podocarps

Podocarpaceae

Podocarpaceae is a large family of mainly Southern Hemisphere conifers, comprising about 156 species of evergreen trees and shrubs. It contains 19 genera if Phyllocladus is included and if Manoao and Sundacarpus are recognized....

and the southern beeches, but also a distinctive insect fauna, New Zealand's unusual frogs and the tuatara

Tuatara

The tuatara is a reptile endemic to New Zealand which, though it resembles most lizards, is actually part of a distinct lineage, order Sphenodontia. The two species of tuatara are the only surviving members of its order, which flourished around 200 million years ago. Their most recent common...

, as well as some of New Zealand's birds. It seems likely that some primitive mammals also were part of the original cargo. Whether or not any of these taxa are descendents of survivors of that ancient cargo remains unproven. Recent molecular evidence has shown that even the iconic Gondwanan plants the southern beeches (Nothofagus) arrived in New Zealand after separation of Zealandia from Gondwana.

The two sources of New Zealand's biodiversity following separation from Gondwana have been speciation

Speciation

Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...

and air- or sea-borne immigration. Most of these immigrants have arrived from Australia, and have provided the majority of New Zealand's birds and bat

Bat

s as well as some plant species (carried on the wind or inside the guts of birds). Some of these immigrants arrived long enough ago that their affinities to their Australian ancestors are uncertain; for example, the affinities of the unusual short-tailed bats (Mystacinidae

Mystacinidae

Mystacinidae is a family of unusual bats, the New Zealand short-tailed bats. There is one living genus, Mystacina, with two extant species, one of which is believed to have become extinct in the 1960s. They are medium-sized bats, about in length, with grey, velvety fur.Mystacinids are the most...

) were unknown until fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s from the Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

were found in Australia. Cyanoramphus
Cyanoramphus
Cyanoramphus is a genus of parakeets native to New Zealand and islands of the southern Pacific Ocean. The New Zealand forms are often referred to as kākāriki. They are small to medium sized parakeets with long tails and predominately green plumage. Most species are forest species, although several...

parakeets are thought to have originated in New Caledonia and have been successful at reaching many islands in the region. The link between the two island groups also includes affinities between skink

Skink

Skinks are lizards belonging to the family Scincidae. Together with several other lizard families, including Lacertidae , they comprise the superfamily or infraorder Scincomorpha...

and gecko

Gecko

Geckos are lizards belonging to the infraorder Gekkota, found in warm climates throughout the world. They range from 1.6 cm to 60 cm....

families.

Floral biodiversity

The history, climate and geology of New Zealand have created a great deal of diversity in New Zealand's vegetation types. The main two types of forest have been dominated by podocarps and southern beech. Podocarps (Podocarpaceae), an ancient evergreen

Evergreen

In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...

gymnosperm

Gymnosperm

The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...

family of trees, have changed little in the last 190 million years. Forests dominated by podocarps form a closed canopy with an understory of hardwood

Hardwood

Hardwood is wood from angiosperm trees . It may also be used for those trees themselves: these are usually broad-leaved; in temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen.Hardwood contrasts with softwood...

s and shrubs. The forests of southern beeches, from the genus Nothofagus, comprise a less diverse habitat, with the beeches of four species dominating the canopy and allowing a single understory. In the north of New Zealand the podocarp forests were dominated by the ancient giant kauri

Agathis australis

Agathis australis, commonly known as the kauri, is a coniferous tree found north of 38°S in the northern districts of New Zealand's North Island. It is the largest but not tallest species of tree in New Zealand, standing up to 50 m tall in the emergent layer above the forest's main canopy. The...

. These trees are amongst the largest in the world, holding the record for the greatest timber volume of any tree. The value of this was not lost on early European settlers, and most of these trees were felled.

The remaining vegetation types in New Zealand are grassland

Grassland

Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...

of grass and tussock, usually associated with the subalpine areas, and the low shrublands between grasslands and forests. These shrublands are dominated by daisies

Asteraceae

The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...

, which can become woody and 3 m high.

Faunal diversity

Until 2006 it was thought that no mammal

Mammal

Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s, other than bats and marine mammal

Marine mammal

Marine mammals, which include seals, whales, dolphins, and walruses, form a diverse group of 128 species that rely on the ocean for their existence. They do not represent a distinct biological grouping, but rather are unified by their reliance on the marine environment for feeding. The level of...

s, had reached New Zealand before humans did. The discovery of a femur

Femur

The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...

and mandible

Mandible

The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...

s of an extinct non-volant (non-flying) mammal in Otago

Otago

Otago is a region of New Zealand in the south of the South Island. The region covers an area of approximately making it the country's second largest region. The population of Otago is...

, dated at 16–19 million years old, has changed the view of New Zealand's evolutionary history, as it strongly suggests that mammals had been part of New Zealand's fauna since the break-up of Gondwana. The fossil has been called SB mammal. It is not known when, or why, land mammals went extinct in New Zealand but there were none present on New Zealand for several million years before the arrival of man.

The short-tailed bats (from the monotypic family Mystacinidae

Mystacinidae

), having arrived in the late Oligocene

Oligocene

The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

, have had plenty of time to evolve

Evolution

Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

, and had begun to fill the role of a small terrestrial mammal, flying out from roosts at night but frequently foraging on the ground. Some plants have evolved with the bats and are fertilised on the ground by the bats. The Long-tailed Bat (Chalinolobus tuberculatus), a more recent arrival, is relatively common.

Birds comprise the most important part of New Zealand's vertebrate

Vertebrate

Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...

fauna. It is uncertain if many birds in New Zealand are descended from Gondwanan stock, as DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

evidence suggests that even the ratite

Ratite

A ratite is any of a diverse group of large, flightless birds of Gondwanan origin, most of them now extinct. Unlike other flightless birds, the ratites have no keel on their sternum—hence the name from the Latin ratis...

s (the kiwi

Kiwi

Kiwi are flightless birds endemic to New Zealand, in the genus Apteryx and family Apterygidae.At around the size of a domestic chicken, kiwi are by far the smallest living ratites and lay the largest egg in relation to their body size of any species of bird in the world...

s and the moa

Moa

The moa were eleven species of flightless birds endemic to New Zealand. The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about in height with neck outstretched, and weighed about ....

s) arrived after the split from Antarctica. Recent studies suggest that New Zealand wren

New Zealand wren

The New Zealand wrens, Acanthisittidae, are a family of tiny passerines endemic to New Zealand. They were represented by six known species in four or five genera, although only two species survive in two genera today...

s are Gondwanan descendants. DNA studies seem to indicate that the wrens are the most ancient of all passerines, splitting from the ancestral passerine stock at the time New Zealand become an isolated land mass. In the absence of mammals, birds diversified into the niche

Ecological niche

In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...

s usually filled by mammals in other ecosystems.

The moas, of which there were 10 species, were large browsers, and were in turn the prey species of the giant Haast's Eagle

Haast's Eagle

Haast's Eagle was a species of massive eagles that once lived on the South Island of New Zealand. The species was the largest eagle known to have existed. Its prey consisted mainly of gigantic flightless birds that were unable to defend themselves from the striking force and speed of these eagles,...

or Harpagornis Eagle. Both the moas and the eagle became extinct shortly after the arrival of humans in New Zealand sometime around 1300 CE. It appears that human hunters exterminated the moa populations, which deprived the Harpagornis of its primary food source, leading to the extinction of that species as well. New Zealand's emblematic kiwis fill the role of small foragers of the leaf-litter, and the enigmatic adzebill

Adzebill

The adzebills, genus Aptornis, were two closely related bird species, the North Island Adzebill, Aptornis otidiformis, and the South Island Adzebill, Aptornis defossor, of the extinct family Aptornithidae. The family was endemic to New Zealand.They have been placed in the Gruiformes but this is not...

was a universal omnivore. The wattlebirds, Callaeidae

Callaeidae

The small bird family Callaeidae is endemic to New Zealand. It contains three monotypic genera; of the three species in the family, only two survive and both of them, the Kokako and the Saddleback, are endangered species, threatened primarily by the predations of introduced mammalian species such...

, are a family endemic to New Zealand, but many other New Zealand birds show clear affinities to Australia, including the New Zealand Pigeon

Kereru

The New Zealand Pigeon or kererū is a bird endemic to New Zealand. Māori call it Kererū in most of the country but kūkupa and kūkū in some parts of the North Island, particularly in Northland...

and the New Zealand Falcon, as well as various parrots, rail

Rallidae

The rails, or Rallidae, are a large cosmopolitan family of small to medium-sized birds. The family exhibits considerable diversity and the family also includes the crakes, coots, and gallinules...

s, wader

Wader

Waders, called shorebirds in North America , are members of the order Charadriiformes, excluding the more marine web-footed seabird groups. The latter are the skuas , gulls , terns , skimmers , and auks...

s, owl

Owl

Owls are a group of birds that belong to the order Strigiformes, constituting 200 bird of prey species. Most are solitary and nocturnal, with some exceptions . Owls hunt mostly small mammals, insects, and other birds, although a few species specialize in hunting fish...

s, and seabird

Seabird

Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...

s (albeit often with a New Zealand twist). Of the 245 species of birds from the greater New Zealand (the main islands along with the offshore islands, also including Norfolk Island

Norfolk Island

Norfolk Island is a small island in the Pacific Ocean located between Australia, New Zealand and New Caledonia. The island is part of the Commonwealth of Australia, but it enjoys a large degree of self-governance...

), 174 were endemic, roughly 71%. Of these, about 32% of the genera

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

were endemic.

No agama

Agamidae

Agamids, lizards of the family Agamidae, include more than 300 species in Africa, Asia, Australia, and a few in Southern Europe. Many species are commonly called dragons or dragon lizards. Phylogenetically they may be sister to the Iguanidae, and have a similar appearance. Agamids usually have...

s, iguana

Iguana

Iguana is a herbivorous genus of lizard native to tropical areas of Central America and the Caribbean. The genus was first described in 1768 by Austrian naturalist Josephus Nicolaus Laurenti in his book Specimen Medicum, Exhibens Synopsin Reptilium Emendatam cum Experimentis circa Venena...

s or land turtles are recorded from New Zealand. The fossil record shows one crocodile, possibly a mekosuchine crocodile, in the Miocene

Miocene

, but otherwise the only reptile

Reptile

Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...

s to reach New Zealand were skink

Skink

Skinks are lizards belonging to the family Scincidae. Together with several other lizard families, including Lacertidae , they comprise the superfamily or infraorder Scincomorpha...

s, gecko

Gecko

Geckos are lizards belonging to the infraorder Gekkota, found in warm climates throughout the world. They range from 1.6 cm to 60 cm....

s, and the tuatara

Tuatara

, a living fossil

Living fossil

Living fossil is an informal term for any living species which appears similar to a species otherwise only known from fossils and which has no close living relatives, or a group of organisms which have long fossil records...

. The tuatara, reaching 60 cm (23.6 inches), is New Zealand's largest reptile. Frogs, which because of their intolerance for saltwater

Seawater

Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...

are assumed to have descended from ancestors that broke off from Gondwana, are one of the few exceptions to the rule that amphibians are never found on oceanic islands (another being the frogs of Fiji). New Zealand's few wholly freshwater fishes are derived from diadromous

Fish migration

Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres...

species.
New Zealand's invertebrate community displays strong Gondwanan affinities, and has also diversified strongly, if unevenly. There are over a thousand species of snail

Snail

Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

, and many species of insect have become large and in many cases flightless, especially grasshopper

Grasshopper

The grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as the short-horned grasshopper...

s and beetle

Beetle

Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...

s. There are, however, fewer than 12 species of ant

Ant

Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...

. The most famous of New Zealand's insects, the weta

Weta

Weta is the name given to about 70 insect species endemic to New Zealand. There are many similar species around the world, though most are in the southern hemisphere. The name comes from the Māori word 'wētā' and is the same in the plural...

s, are ground-living relatives of the cricket

Cricket (insect)

Crickets, family Gryllidae , are insects somewhat related to grasshoppers, and more closely related to katydids or bush crickets . They have somewhat flattened bodies and long antennae. There are about 900 species of crickets...

s that often reach enormous proportions.

Endemism

New Zealand has a high number of endemic species:

80% of all vascular plants
70% of all native terrestrial and freshwater birds
All bats
All native amphibians
All reptiles
90% of freshwater fish

Of New Zealand's estimated 20,000 fungi species, only about 4,500 are known. New Zealand also has two sub-species of endemic cetacea

Cetacea

The order Cetacea includes the marine mammals commonly known as whales, dolphins, and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal", was more general. It comes from Ancient Greek , meaning "whale" or "any huge fish or sea...

ns, Hector's Dolphin

Hector's Dolphin

Hector's dolphin is the best-known of the four dolphins in the genus Cephalorhynchus and is found only in New Zealand. At about 1.4 m in length, it is one of the smallest cetaceans....

and its close relative Maui's Dolphin

Maui's dolphin

Maui's dolphin is the world's smallest known species of dolphin. They are a sub-species of the Hector's dolphin....

Human impact

The arrival of humans in New Zealand has presented a challenge for the native species, causing the extinction

Extinction

In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...

of several. This is predominantly because many species in New Zealand have evolved in the absence of mammalian predators for the last few million years (a situation known as ecological naivety), thus losing the responses needed to deal with such threats. Humans brought with them

Introduced species

An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...

to New Zealand (intentionally or otherwise) a host of attendant species, starting with the Polynesian Rat

Polynesian Rat

The Polynesian Rat, or Pacific Rat , known to the Māori as kiore, is the third most widespread species of rat in the world behind the Brown Rat and Black Rat. The Polynesian Rat originates in Southeast Asia but, like its cousins, has become well travelled – infiltrating Fiji and most Polynesian...

, and now including stoat

Stoat

The stoat , also known as the ermine or short-tailed weasel, is a species of Mustelid native to Eurasia and North America, distinguished from the least weasel by its larger size and longer tail with a prominent black tip...

s, weasel

Weasel

Weasels are mammals forming the genus Mustela of the Mustelidae family. They are small, active predators, long and slender with short legs....

s, Black Rat

Black Rat

The black rat is a common long-tailed rodent of the genus Rattus in the subfamily Murinae . The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world.-Taxonomy:The black rat was...

s, Norway Rats, Brushtailed Possum

Common Brushtail Possum

The Common Brushtail Possum is a nocturnal, semi-arboreal marsupial of the family Phalangeridae, it is native to Australia, and the largest of the possums.Like most possums, the Common Brushtail is nocturnal...

s, and feral cat

Feral cat

A feral cat is a descendant of a domesticated cat that has returned to the wild. It is distinguished from a stray cat, which is a pet cat that has been lost or abandoned, while feral cats are born in the wild; the offspring of a stray cat can be considered feral if born in the wild.In many parts of...

s and dogs, as well as herbivores such as deer

Deer

Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

, wallabies and tahr

Tahr

Tahrs are three species of large Asian ungulates related to the wild goat. Until recently the three species were believed to be closely related and were placed in a single genus, Hemitragus. Genetic studies have proved that the three tahrs are not as closely related as thought earlier...

(a wild goat species from the Himalayas), which detrimentally affect native vegetation.

The date of the first arrival of the Māori in New Zealand is given as around 1300 CE, but some recent evidence suggests that Polynesia

Polynesia

Polynesia is a subregion of Oceania, made up of over 1,000 islands scattered over the central and southern Pacific Ocean. The indigenous people who inhabit the islands of Polynesia are termed Polynesians and they share many similar traits including language, culture and beliefs...

n travellers arrived earlier, as Polynesian Rats seemed to have arrived in 500 CE. Their arrival set off a first wave of extinctions, eliminating smaller defenceless ground nesting birds such as the New Zealand Owlet-nightjar

New Zealand Owlet-nightjar

The New Zealand Owlet-nightjar, Aegotheles novazelandiae, was a large species of owlet-nightjar formerly endemic to the islands of New Zealand. Fossil remains indicate the species was once widespread across both North Island and South Island...

. A second wave of extinctions was triggered by the arrival of the Māori, who hunted many of the larger species, such as the moa, adzebill and several large ducks and geese, for food. The Harpagornis and Eyles's Harrier are thought to have gone extinct due to the loss of their food source. A third wave of extinction began with the arrival of European settlers, who brought with them numerous new mammal species, particularly the predatory domestic cat, and initiated more habitat modification. In all, over 50% of New Zealand's bird species are considered extinct, along with a species of bat and several frogs, a freshwater fish (the New Zealand greyling), skinks and geckos; this is second only to Hawaii in terms of proportion of species lost.

In some instances, the extinction of New Zealand's native fauna has brought about a natural colonisation from Australia. In the case of the Silvereye

Silvereye

The Silvereye or Wax-eye is a very small passerine bird native to Australia, New Zealand and the south-west Pacific islands of Lord Howe, New Caledonia, Loyalty Islands, Vanuatu, and Fiji...

, which colonised New Zealand in the 19th century, it had no relative in New Zealand's original fauna and is now restricted to newer man-made niche

Ecological niche

s. In the case of the Black Swan

Black Swan

The Black Swan is a large waterbird, a species of swan, which breeds mainly in the southeast and southwest regions of Australia. The species was hunted to extinction in New Zealand, but later reintroduced. Within Australia they are nomadic, with erratic migration patterns dependent upon climatic...

(which was originally thought to have been introduced by humans but is now suspected to have self-introduced), the invading species re-occupied part of its former range (the extinct New Zealand Swan

New Zealand Swan

The New Zealand Swan is an extinct swan from the Chatham Islands and the South Island of New Zealand. It was originally described as a separate species from the Black Swan based on the slightly larger size of the fossil bones found and the apparent absence of the Black Swan from New Zealand prior...

is now believed to be a subspecies of the Black Swan). The arrival of the Pukeko and the Swamp Harrier

Swamp Harrier

The Swamp Harrier also known as the Marsh Harrier, Australasian Harrier, Kāhu, Swamp-hawk or New Zealand Hawk is a large, slim bird of prey in the family Accipitridae.-Description:...

is more interesting, mirroring the arrival of the same two species in the past, before they evolved into the Takahe

Takahe

The Takahē or South Island Takahē, Porphyrio hochstetteri is a flightless bird indigenous to New Zealand and belonging to the rail family. It was thought to be extinct after the last four known specimens were taken in 1898...

and the Eyles's Harrier. Once these specialised birds declined and (in the case of the harrier) went extinct, their niches were available and colonisation could occur again.

Management

Today New Zealand's species are amongst the most threatened in the world. The New Zealand government, through the Department of Conservation

New Zealand Department of Conservation

The Department of Conservation , commonly known by its acronym, "DOC", is the state sector organisation which deals with the conservation of New Zealand’s natural and historic heritage...

, works aggressively to protect what remains of New Zealand's biological heritage. It has pioneered work on island restoration

Island restoration

The ecological restoration of islands, or island restoration, is the application of the principles of ecological restoration to islands and island groups. Islands, due to their isolation, are home to many of the world's endemic species, as well as important breeding grounds for seabirds and some...

where offshore islands are systematically cleared of introduced species such as goats, feral cats and rats. This then allows the re-introduction of native species that can hopefully flourish in the absence of non-native predators. The longest running project of this type is on Cuvier Island

Cuvier Island

Cuvier Island is a small island off the east coast of the North Island of New Zealand. It lies on the seaward end of the Colville Channel, north of the Mercury Islands and approximately south-east of Great Barrier Island...

, but other islands are also being used such as Tiritiri Matangi and Mangere Island

Mangere Island

Mangere Island is part of the Chatham Islands archipelago, located east of New Zealand's South Island and has an area of . The island lies off the west coast of Pitt Island, south-east of the main settlement in the Chathams, Waitangi, on Chatham Island....

.
Establishment of conservation areas is not restricted to islands however and several ecological island

Ecological island

An ecological island is not necessarily an island surrounded by water, but is an area of land, isolated by natural or artificial means from the surrounding land, where a natural micro-habitat exists amidst a larger differing ecosystem....

s have been established on the New Zealand mainland which are isolated by the use of pest-exclusion fence

Pest-exclusion fence

thumb|280px|Xcluder pest-exclusion fence around perimeter of [[Maungatautari Restoration Project|Maungatautari]]A pest-exclusion fence is built to exclude certain types of animal pests from an enclosure...

General references

Ericson P, Christidis L, Cooper, A, Irestedt M, Jackson J, Johansson US, Norman JA. (2002). "A Gondwanan origin of passerine birds supported by DNA sequences of the endemic New Zealand wrens". Proc Biol Sci. 269(1488):235-41.
Worthy, Trevor H., & Holdaway, Richard N. (2002). The Lost World of the Moa. Bloomington: Indiana University Press. ISBN 0-253-34034-9
Worthy TH, Tennyson AJ, Archer M, Musser AM, Hand SJ, Jones C, Douglas BJ, McNamara JA, Beck RM (2006). "Miocene mammal reveals a Mesozoic ghost lineage on insular New Zealand, southwest Pacific." Proceedings of the National Academy of Sciences 103; 19419-23
Segedin, B.P.; Pennycook, S.R. (2001). "A nomenclatural checklist of agarics, boletes, and related secotioid and gasteromycetous fungi recorded from New Zealand". New Zealand Journal of Botany, Vol. 39: 285–348, doi:0028-825X/01/3902-0285

External links

New Zealand Biodiversity – Government web site.
National Aquatic Biodiversity Information System
New Zealand Species- Significant collection of high resolution images. Free for non profit school use.
Biodiversity and Conservation at Landcare Research
New Zealand Plant Conservation Network website for information about the indigenous flora and species of introduced weed and animal pests

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Evolution

Floral biodiversity

Faunal diversity

Endemism

Human impact

Management

See also

General references

Further reading

External links