The biodiversity of Tasmania is of biological and paleoecological interest. A state of Australia, it is a large South Pacificarchipelago of one large main island and a range of smaller islands. The terrain includes a variety of reefs, atolls, small islands, and a variety of topographical and edaphic regions on the largest island, all of which promote the development of concentrated biodiversity. During long periods geographically and genetically isolated, it is known for its unique flora and fauna. The region's climate is oceanic.
The marine fauna of the period, separate from that of the southwest Pacific, was distinguished as the "Maori province". Gondwana began its fragmentation in the middle and upper Jurassic, and the arrival of benthicinvertebrate fauna is visible in fossil deposits. The Cretaceous marked the appearance of marine invertebrate fauna of southern origin. It was then that angiosperm flora such as Nothofagaceae and Proteaceae colonized New Zealand and New Caledonia, from South America, along the Antarctic margin of Gondwana: Antarctica, mainland Australia and Tasmania. At the beginning of the Tertiary the area moved to north to a warmer climate.
This led to long periods of evolution in near complete isolation. The isolation of the island was not absolute, given the rise and fall of sea level caused by the ebb and flow of ice ages. Land bridges or islands formed between Tasmania and its neighbour, mainland Australia. Thus new species came to Tasmania while Gondwanan species were able to penetrate the Pacific Islands region. Plants have limited seed dispersal mobility away from the parent plant and consequently rely upon a variety of dispersal vectors to transport their propagules, including both abiotic and biotic vectors. Seeds can be dispersed away from the parent plant individually or collectively, as well as dispersed in both space and time. Birds and bats swallow seeds, then regurgitate them or pass them in their faeces. This has been a major mechanism of seed dispersal across ocean barriers. Other seeds may stick to the feet or feathers of birds, particularly migratory or aquatic birds, and in this way travel long distances. Seeds of grasses, spores of algae, and the eggs of molluscs and other invertebrates commonly establish in remote areas after long journeys of such types.
The most ancient communities in Tasmania have an ancestry that extend back to a time when the Earth's continents were all joined as single landmass known as Pangaea which existed more than 200 million years ago. Pangaea split from east to west into Laurasia, comprising North America and Eurasia, and Gondwana, the two remaining connected at Gibraltar with the Tethys Sea separating them. The presence of closely related organisms in both the Northern and Southern Hemispheres cannot be accounted for by migration.
The Antarctic flora is a distinct community of vascular plants which evolved millions of years ago on the supercontinent of Gondwana, and is now found on several separate areas of the Southern Hemisphere, including southern South America, southernmost Africa, New Zealand, Australia and New Caledonia. Based on the similarities in their flora, botanist Ronald Good identified a separate Antarctic floristic kingdom that included southern South America, New Zealand, and some southern island groups. Good identified Australia as its own floristic kingdom, and included New Guinea and New Caledonia in the Paleotropical floristic kingdom, because of the influx of tropical Eurasian flora that had mostly supplanted the Antarctic flora.
Millions of years ago, Antarctica was warmer and much wetter, and supported the Antarctic flora, including forests of podocarps and southern beech. Antarctica was also part of the ancient supercontinent of Gondwanaland, which gradually broke up by continental drift starting 110 million years ago. The separation of South America from Antarctica 30to 35 million years ago allowed the Antarctic Circumpolar Current to form, which isolated Antarctica climatically and caused it to become much colder. The Antarctic flora subsequently died out there, but is still an important component of the flora of southern Neotropic (South America) and Australasia, which were also former parts of Gondwana.
Some genera that originated in Antarctic flora are still a recognised major component of New Caledonia, Tasmania, mainland Australia, Madagascar, India, New Zealand, and southern South America.
Deciduous beech (Nothofagus gunnii) occurs in mountainous parts of Tasmania. Antarctic beech (Nothofagus moorei) is found in eastern New South Wales' cool temperate rainforests and cloud forests, but does not occur in Victoria or Tasmania.
Australia rafted north and became drier; the humid Antarctic flora retreated to the mainland east coast and Tasmania, while much of the rest of Australian vegetation became dominated by Acacia, Eucalyptus, Casuarina and xeric shrubs and grasses. Humans arrived in Australia 50 to 60,000 years ago, and used fire to reshape the vegetation of the continent.
Investigations of Upper Cretaceous and Early Tertiary sediments of Antarctica yield a rich assemblage of well-preserved fossil dicotyledonous angiosperm wood which provides evidence for the existence, since the Late Cretaceous, of temperate forests similar in composition to those found in present-day southern South America, New Zealand, Australia and Tasmania. It is suggested a paleobotanical habitat similar to the extant cool temperate Valdivian rainforests.[2]
Tasmania has extremely diverse vegetation, from the heavily grazed grassland of the dry midlands to the tall evergreen eucalypt forest, alpine heathlands and large areas of cool temperate rainforests and moorlands in the rest of the state. Many flora species are unique to Tasmania, and some are related to species in South America and New Zealand through ancestors which grew on the super continent of Gondwana in the Paleotropical kingdom, 50 million years ago.
Wet eucalypt forests grow mostly in the south, west and north west, the Tasman Peninsula, and higher altitude areas of north east. Dry eucalypt forests grow where there is little rainfall and droughts are common. Areas such as the east coast, midlands and north east, i.e. the Bass Strait Islands.
Tasmania is home to some of the oldest trees of the world. For example, some individual Huon pines are more than 2,000 years old. A clonal stand of male Huon pines at Mount Read maintained itself by vegetative reproduction for what is estimated to be more than 10,000 years.[3]
For millions of years these types of vegetation covered much of Earth's tropics. The species in Tasmania are relicts of a type of vegetation which once covered much of Australia, South America, Antarctica, South Africa, North America[citation needed] and other lands when their climates were warmer and more humid. Although humid forests of warmer climates retreated during the glaciations, they re-colonised large areas every time the climate was favourable again. Most of the humid forests are thought to have retreated and advanced during successive geological eras, and their species adapted to warm and wet gradually retreated and advanced, replaced by more cold-tolerant or drought-tolerant sclerophyll plant communities. Many of the then existing species became extinct because they could not cross the barriers posed by new oceans, mountains and deserts, but others found refuge as relict species in coastal areas and islands.
When the large landmass of the Australian continent developed a drier and harsher climate, this type of forest was reduced to those boundaries areas. Although some remnants of archaic flora still persisted in coastal mountains and sheltered sites, their biodiversity was reduced. In times of high sea level such as the present era, Tasmania as an island, has a climate moderated by the Southern and Pacific Oceans and maintained relatively high rainfall and humidity, which has allowed these communities to persist to the present day.
The ecological requirements of many of the species, are those of the laurel forest and like most of their counterpart laurifolia in the world, they are vigorous species with a great ability to populate their preferred habitats. The geographical isolation and special edaphic conditions helped to preserve it too.
Many members of the late Cretaceous - early Tertiary Gondwanan flora survived in Tasmania and New Caledonia's equable climate.[7]
Fauna
The invertebrates provide abundant evidence of Gondwanan ancestry. Possibly the best known example is the "mountain shrimp", Anaspides tasmaniae (Anaspidesidae), which is very similar to Triassic (230-million-year-old) fossils. Currently, its closest relatives are found in New Zealand and South America. The Tasmanian cave spider is considered to be one of the most primitive spiders in the world, and is the only member of its family outside Chile.
The vertebrates with strong Gondwanan affinities include the major family of freshwater fish Galaxiidae, the two families of frogs within Tasmania (Myobatrachidae and Hylidae) and the parrots. Echidnas and platypus evolved from ancient ancestors which inhabited Gondwana too. Close relatives of marsupials thrive in South America and fossil platypus have also been discovered in South America.
The repeated lowering of sea levels during the ice ages of the Pleistocene facilitated the movement of many species more, including the five species of rodent and eight species of bat.
The island of Tasmania was home to the thylacine, a marsupial which resembled a wild dog. Known colloquially as the Tasmanian tiger for the distinctive striping across its back, it became extinct in mainland Australia about 4,000 years ago because of competition with the introduced dingo. Owing to persecution by farmers, government-funded bounty hunters and, in the final years, collectors for overseas museums, it appears to have been exterminated in Tasmania.
The thylacine was the largest known carnivorous marsupial of modern times. The thylacine was one of only two marsupials to have a pouch in both sexes (the other is the water opossum). The male thylacine had a pouch that acted as a protective sheath, protecting the male's external reproductive organs while running through thick brush. The last known animal died in captivity in 1936. Many alleged sightings have since been recorded, none of them confirmed. The mature thylacine ranged from 100 to 130cm (39 to 51in) long, plus a tail of around 50 to 65cm (20 to 26in).[8] The largest measured specimen was 290cm (9.5ft) from nose to tail. Adults stood about 60cm (24in) at the shoulder and weighed 20 to 30kg (40 to 70lb).[8] There was slight sexual dimorphism with the males being larger than females on average.[9]
The Tasmanian devil is a carnivorousmarsupial found on the island of Tasmania. It also occurred on mainland Australia thousands of years ago. The size of a small dog but stocky and muscular, the Tasmanian devil is characterised by black fur with white patches. It has a loud and disturbing screech-like growl, possesses a vicious temperament and is predominantly a scavenger. The Tasmanian devil survived European settlement and was considered widespread and common throughout Tasmania until recently. As with a lot of wildlife, fast vehicles on roads are a problem for Tasmanian devils, which are often killed while feeding on other road-killed animals such as wallabies. They eat everything including bone.
As of 2005, the Tasmanian devil population has been reduced by up to 80% in parts of Tasmania by the devil facial tumour disease, which is gradually spreading throughout the island. It is believed most of the effected devils starve when the tumours spread to their mouths, and that the tumours are spread by fighting over the carcasses they feed on—typically, fighting devils will bite one another's faces.
There is no known cure for the disease, and intensive research is underway to determine its cause. There is also a captive breeding program being undertaken by the Tasmanian government to establish a disease-free, genetically diverse population of Tasmanian devils outside Tasmania. This has been relatively successful so far.
Tasmania is home to 11 species of frog. Three of these are found only in Tasmania, the Tasmanian tree frog (Litoria burrowsae), the Tasmanian froglet (Crinia tasmaniensis) and the moss froglet (Bryobatrachus nimbus) described in 1994. Of the 11 species that inhabit Tasmania all are endemic to Australia. Tasmania is home to the largest breeding population of growling grass frogs (Litoria raniformis), a vulnerable species, which has declined over much of its range.
European red fox
On 20 June 2001, Tasmania formed a fox task force, now the Fox Eradication Branch, to eliminate the European red fox. Officials planned to spend up to A$50 million on an eradication campaign, which has since been reduced. No foxes have been captured, poisoned or photographed with certainty in the island state, although four carcasses have been recovered. Of these, one was claimed to be shot, and the other three presumed road-kills. The lack of an abundance of foxes, through low population densities, and fox-poisoning campaigns, has resulted in an abundance of denial of fox presence in Tasmania. Established foxes in Tasmania could devastate native mammals, livestock, ground-nesting birds and native rodents. Experts estimate there are fewer than 30 million foxes on mainland Australia, having been introduced by European settlers.[10]
Since settlement, about 28 native mammal species or subspecies have become extinct from the Australian mainland, the worst rate of continental extinction in the world. Red foxes are known to be a significant contributing factor to this. Mainland extinctions or near-extinctions include the eastern barred bandicoot, eastern quoll, and Tasmanian pademelon (Thylogale billardierii); all still common in Tasmania. A member of the upper house, the Legislative Council member for Windermere Ivan Dean has been publicly critical of the evidence used to obtain funding for a taxpayer funded Fox Eradication Branch of the Tasmanian D.P.I.P.W.E. Former Tasmanian Police Commander Dean led an investigation into the alleged importation and release of foxes into Tasmania. The investigation did not uncover any evidence of illegal importation. He then raised the Tasmanian fox issue in the Tasmanian Parliament on 17 April 2007.[11]
In addition to the four carcasses, over 40 independently tested fox-DNA-confirmed scats have been located across Tasmania. Through government review, foxes are now confirmed to be in Tasmania.[12] Certain prominent Tasmanians [who?] including Dr David Obendorf have been calling for a Federal Police investigation into allegations that evidence has been planted and this is all part of an elaborate hoax to receive funding from the Commonwealth.[13]
The thylacine, also commonly known as the Tasmanian tiger or Tasmanian wolf, is an extinct carnivorous marsupial that was native to the Australian mainland and the islands of Tasmania and New Guinea. The thylacine died out in New Guinea and mainland Australia around 3,600–3,200 years ago, prior to the arrival of Europeans, possibly because of the introduction of the dingo, whose earliest record dates to around the same time, but which never reached Tasmania. Prior to European settlement, around 5,000 remained in the wild on Tasmania. Beginning in the nineteenth century, they were perceived as a threat to the livestock of farmers and bounty hunting was introduced. The last known of its species died in 1936 at Hobart Zoo in Tasmania. The thylacine is widespread in popular culture and is a cultural icon in Australia.
Freycinet National Park is a national park on the east coast of Tasmania, Australia, 125 kilometres (78 mi) northeast of Hobart. It occupies a large part of the Freycinet Peninsula, named after French navigator Louis de Freycinet, and Schouten Island. Founded in 1916, it is Tasmania's oldest park, along with Mount Field National Park. Bordering the national park is the small settlement of Coles Bay, and the largest nearby town is Swansea. Freycinet contains part of the rugged Tasmanian coastline and includes the secluded Wineglass Bay. Features of the park include its red and pink granite formations and a series of jagged granite peaks in a line, called "The Hazards".
The Queensland tropical rain forests ecoregion covers a portion of the coast of Queensland in northeastern Australia and belongs to the Australasian realm. The forest contains the world's best living record of the major stages in the evolutionary history of the world's land plants, including most of the world's relict species of plants from the ancient supercontinent of Gondwana. The history of the evolution of marsupials and songbirds is also well represented.
Malesia is a biogeographical region straddling the Equator and the boundaries of the Indomalayan and Australasian realms, and also a phytogeographical floristic region in the Paleotropical Kingdom. The original definition by the World Geographical Scheme for Recording Plant Distributions included Papuasia, but this was split off in its 2001 version.
Nothofagus, also known as the southern beeches, is a genus of 43 species of trees and shrubs native to the Southern Hemisphere in southern South America and east and southeast Australia, New Zealand, New Guinea, and New Caledonia. The species are ecological dominants in many temperate forests in these regions. Some species are reportedly naturalised in Germany and Great Britain. The genus has a rich fossil record of leaves, cupules, and pollen, with fossils extending into the late Cretaceous period and occurring in Australia, New Zealand, Antarctica, and South America.
Antarctic flora are a distinct community of vascular plants which evolved millions of years ago on the supercontinent of Gondwana. Presently, species of Antarctica flora reside on several now separated areas of the Southern Hemisphere, including southern South America, southernmost Africa, New Zealand, Australia, and New Caledonia. Joseph Dalton Hooker was the first to notice similarities in the flora and speculated that Antarctica had served as either a source or a transitional point, and that land masses now separated might formerly have been adjacent.
The Tasmanian temperate rain forests are a temperate broadleaf and mixed forests ecoregion in western Tasmania. The ecoregion is part of the Australasian realm, which includes Tasmania and Australia, New Zealand, New Guinea, New Caledonia, and adjacent islands.
The Antarctic realm is one of eight terrestrial biogeographic realms. The ecosystem includes Antarctica and several island groups in the southern Atlantic and Indian oceans. The continent of Antarctica is so cold that it has supported only 2 vascular plants for millions of years, and its flora presently consists of around 250 lichens, 100 mosses, 25–30 liverworts, and around 700 terrestrial and aquatic algal species, which live on the areas of exposed rock and soil around the shore of the continent. Antarctica's two flowering plant species, the Antarctic hair grass and Antarctic pearlwort, are found on the northern and western parts of the Antarctic Peninsula. Antarctica is also home to a diversity of animal life, including penguins, seals, and whales.
Laurel forest, also called laurisilva or laurissilva, is a type of subtropical forest found in areas with high humidity and relatively stable, mild temperatures. The forest is characterized by broadleaf tree species with evergreen, glossy and elongated leaves, known as "laurophyll" or "lauroid". Plants from the laurel family (Lauraceae) may or may not be present, depending on the location.
The biodiversity of New Caledonia is of exceptional biological and paleoecological interest. It is frequently referred to as a biodiversity hotspot. The country is a large South Pacific archipelago with a total land area of more than 18,000 square kilometres (6,900 sq mi). The terrain includes a variety of reefs, atolls, small islands, and a variety of topographical and edaphic regions on the largest island, all of which promote the development of unusually concentrated biodiversity. The region's climate is oceanic and tropical.
Tasmania, the largest island of Australia, has a landmass of 68,401 km2 (26,410 sq mi) and is located directly in the pathway of the notorious "Roaring Forties" wind that encircles the globe. To its north, it is separated from mainland Australia by Bass Strait. Tasmania is the only Australian state that is not located on the Australian mainland. About 2,500 kilometres south of Tasmania island lies the George V Coast of Antarctica. Depending on which borders of the oceans are used, the island can be said to be either surrounded by the Southern Ocean, or to have the Pacific on its east and the Indian to its west. Still other definitions of the ocean boundaries would have Tasmania with the Great Australian Bight to the west, and the Tasman Sea to the east. The southernmost point on mainland Tasmania is approximately 43°38′37″S146°49′38″E at South East Cape, and the northernmost point on mainland Tasmania is approximately 40°38′26″S144°43′33″E in Woolnorth / Temdudheker near Cape Grim / Kennaook. Tasmania lies at similar latitudes to Te Waipounamu / South Island of New Zealand, and parts of Patagonia in South America, and relative to the Northern Hemisphere, it lies at similar latitudes to Hokkaido in Japan, Northeast China (Manchuria), the north Mediterranean in Europe, and the Canada-United States border.
The New Caledonia rain forests are a terrestrial ecoregion, located in New Caledonia in the South Pacific. It is a tropical moist broadleaf forest ecoregion, part of the Australasian realm.
Nothofagus moorei, commonly known as Antarctic beech, is an important Gondwana relict of the rainforests of the southern hemisphere. It occurs in wet, fire-free areas at high altitude in eastern Australia.
The Antarctic floristic kingdom, also the Holantarctic kingdom, is a floristic kingdom that includes most areas of the world south of 40°S latitude. It was first identified by botanist Ronald Good, and later by Armen Takhtajan. The Antarctic Floristic Kingdom is a classification in phytogeography, different from the Antarctic realm classification in biogeography, and from Antarctic flora genera/species classifications in botany.
The Paleotropical kingdom (Paleotropis) is a floristic kingdom composed of the tropical areas of Africa, Asia and Oceania, as proposed by Ronald Good and Armen Takhtajan. Part of its flora is inherited from the ancient supercontinent of Gondwana or exchanged later. These Gondwanan lineages are related to those in the Neotropical kingdom, composed of the tropical areas of Central and South America. Flora from the Paleotropical kingdom influenced the tropical flora of the Australian Kingdom. The kingdom is subdivided into five floristic subkingdoms according to Takhtajan and about 13 floristic regions. In this article the floristic subkingdoms and regions are given as delineated by Takhtajan.
The natural history of New Zealand began when the landmass Zealandia – today an almost entirely submerged mass of continental crust with New Zealand and a few other islands peaking above sea level – broke away from the supercontinent Gondwana in the Cretaceous period. Before this time, Zealandia shared its past with Australia and Antarctica. Since this separation, the New Zealand landscape has evolved in physical isolation, although much of its current biota has more recent connections with species on other landmasses. The exclusively natural history of the country ended in about 1300 AD, when humans first settled, and the country's environmental history began. The period from 1300 AD to today coincides with the extinction of many of New Zealand's unique species that had evolved there.
The flora of Australia comprises a vast assemblage of plant species estimated to over 21,000 vascular and 14,000 non-vascular plants, 250,000 species of fungi and over 3,000 lichens. The flora has strong affinities with the flora of Gondwana, and below the family level has a highly endemic angiosperm flora whose diversity was shaped by the effects of continental drift and climate change since the Cretaceous. Prominent features of the Australian flora are adaptations to aridity and fire which include scleromorphy and serotiny. These adaptations are common in species from the large and well-known families Proteaceae (Banksia), Myrtaceae, and Fabaceae.
Richea pandanifolia, the pandani or giant grass tree, is a distinctive endemic Tasmanian angiosperm. It is dicot of the family Ericaceae and is found in central, western and south west Tasmania. It is a favourite among hikers and nature lovers.
Tasmania can be broadly divided into two distinct regions, eastern and western, that exhibit major differences in climate, geology and vegetation. This divide, termed Tyler's Corridor, runs from just south of the northwestern corner, and continues south, cutting roughly down the center of the island. The vegetation changes occur principally due to variations in soil types, which are a result of the geological composition, and the vast difference in climate across the state. Generally, the west has a higher mean rainfall but poor acidic soil while the east has a lower mean rainfall but slightly more fertile soil. This results in a larger proportion of rainforest, moorland and wet sclerophyll vegetation dominating in the west and predominantly dry sclerophyll in the east.
The Tasmanian temperate forests is a temperate broadleaf and mixed forests ecoregion in Australia. The ecoregion occupies the eastern portion of the island of Tasmania, which lies south of the Australian mainland.
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