Flora Flora and fauna of Tasmania
alpine heathland @ high shelf camp near mount anne, in southwest national park. 60% of tasmanian alpine flora endemic state.
the ancient communities in tasmania have ancestry extend time when earth s continents joined single landmass known pangea existed beyond 200 million years ago. pangea split east west laurasia, comprising north america , eurasia, , gondwana, 2 remaining connected @ gibraltar tethys sea separating them. presence of closely related organisms in both northern , southern hemispheres cannot accounted migration.
the tarkine, located in island s far north west, largest temperate rainforest area in australia covering approximately 3,800 square kilometres (1,500 sq mi). temperate rainforest has high diversity of non-vascular plants: mosses, liverworts , lichens representing australia s largest remaining single tract of gondwanan rainforest , largest wildland dominated rainforest in australia. contains approximately 1,800 km of rainforest, around 400 km of eucalypt forest , mosaic of other vegetation communities, including dry sclerophyll forest, woodland, buttongrass moorland, sandy littoral communities, wetlands, grassland , sphagnum communities.
the antarctic flora distinct community of vascular plants evolved millions of years ago on supercontinent of gondwana, , found on several separate areas of southern hemisphere, including southern south america, southernmost africa, new zealand, australia , new caledonia. based on similarities in flora, botanist ronald identified separate antarctic floristic kingdom included southern south america, new zealand, , southern island groups. identified australia own floristic kingdom, , included new guinea , new caledonia in paleotropical floristic kingdom, because of influx of tropical eurasian flora had supplanted antarctic flora.
millions of years ago, antarctica warmer , wetter, , supported antarctic flora, including forests of podocarps , southern beech. antarctica part of ancient supercontinent of gondwanaland, gradually broke continental drift starting 110 million years ago. separation of south america antarctica 30-35 million years ago allowed antarctic circumpolar current form, isolated antarctica climatically , caused become colder. antarctic flora subsequently died out in antarctica, still important component of flora of southern neotropic (south america) , australasia, former parts of gondwana.
some genera originated in antarctic flora still recognised major component of new caledonia, tasmania, mainland australia, madagascar, india, new zealand, , southern south america.
there 3 species of nothofagus in australia. stands of myrtle beech (nothofagus cunninghamii) exist in tarkine forest. there stands of species in great otway national park, central highlands, strzelecki ranges , wilsons promontory national park, of victoria.
deciduous beech (nothofagus gunnii) occurs in mountainous parts of tasmania. antarctic beech (nothofagus moorei) found in eastern nsw cool temperate rainforests , cloud forests, not occur in victoria or tasmania.
australia rafted north , became drier; humid antarctic flora retreated mainland east coast , tasmania, while of rest of australian vegetation became dominated acacia, eucalyptus, casuarina , xeric shrubs , grasses. humans arrived in australia 50-60,000 years ago, , used fire reshape vegetation of continent.
the woody plants of antarctic floristic kingdom include conifers in families podocarpaceae, araucariaceae , subfamily callitroideae of cupressaceae, , angiosperms such families proteaceae, griseliniaceae, cunoniaceae, atherospermataceae, , winteraceae, , genera southern beech (nothofagus) , fuchsia (fuchsia). many other families of flowering plants , ferns, including tree fern dicksonia, characteristic of antarctic flora. in past tasmania omitted since plant species more closely related found in australian floristic kingdom. noted, had joseph dalton hooker earlier, many plant species of antarctica, temperate south america , new zealand closely related, despite disjunction vast southern ocean. tasmania , new caledonia share related species extinct in australia mainland.
investigations of upper cretaceous , tertiary sediments of antarctica yield rich assemblage of well-preserved fossil dicotyledonous angiosperm wood provides evidence existence, since late cretaceous, of temperate forests similar in composition found in present-day southern south america, new zealand, australia , tasmania. suggested paleobotanical habitat similar extant cool temperate valdivian rainforests.
tasmania has extremely diverse vegetation, heavily grazed grassland of dry midlands tall evergreen eucalypt forest, alpine heathlands , large areas of cool temperate rainforests , moorlands in rest of state. many flora species unique tasmania, , related species in south america , new zealand through ancestors grew on super continent of gondwana in paleotropical kingdom, 50 million years ago.
wet eucalypt forests grow in south, west , north west, tasman peninsula, , higher altitude areas of north east. dry eucalypt forests grow there little rainfall , droughts common. areas such east coast, midlands , north east, i.e. bass strait islands.
tasmania home of oldest trees of world. example, individual huon pines recorded more 2,000 years old. clonal stand of male huon pines @ mount read maintained vegetative reproduction estimated more 10,000 years.
the tallest trees in southern hemisphere, , tallest flowering plants anywhere (99 metres (325 ft) tall or more), eucalyptus regnans, eucalyptus globulus , eucalyptus viminalis in tasmania (mostly in styx valley). tasmania hosts endemic plant genera plant genera of restricted distribution; example of such genus archeria.
for millions of years in past, these types of vegetation present in island, covered of tropics of earth. species of tasmania relicts of type of vegetation disappeared, covered of mainland of australia, south america, antarctica, south africa, north america , other lands when climate more humid , warm. although humid forests of warmer climates retreated during glaciations, re-colonised large areas every time climate favourable again. of humid forests thought have retreated , advanced during successive geological eras, , species adapted warm , wet gradually retreated , advanced, replaced more cold-tolerant or drought-tolerant sclerophyll plant communities. many of existing species became extinct because not cross barriers posed new oceans, mountains , deserts, others found refuge relict species in coastal areas , islands.
when large landmass of australian continent developed drier , harsher climate, type of forest reduced boundaries areas. although remnants of archaic rich flora still persisted in coastal mountains , sheltered sites, biodiversity reduced. in times of high sea level such present era, tasmania island, has climate moderated southern , pacific oceans , maintained relatively humid , high rainfall, has allowed these communities persist present day.
the ecological requirements of many of species, of laurel forest , of counterpart laurifolia in world, vigorous species great ability populate preferred habitats. geographical isolation , special edaphic conditions helped preserve too.
many members of late cretaceous - tertiary gondwanan flora survived in tasmania , new caledonia s equable climate.
plants have limited seed dispersal mobility away parents, consequently relying upon variety of dispersal vectors transport propagules, including both abiotic , biotic vectors. seeds can dispersed away parent plant individually or collectively.
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