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Australian Alps montane grasslands

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Kosciuszko NP, New South Wales, Australia. Photograph by Peter Sundstrom

The Australia Alps montane grasslands is a high elevation prairie within the Australian Alps mountain range, manifesting as a disjunctive set of geographic units.  Ancient rocks were gradually uplifted over a timespan of around 50 million years to form the Australian Alps, the southeastern section of the Great Dividing Range. Extending over 500 kilometers (km), largely through state-owned land, the Alps are an ecoregion like no other in low-lying, arid, drought-prone Australia. The higher elevations of the Australian Alps receive regular precipitation, supporting a thriving mix of grasslands, heath, and bogs above the treeline, as well as montane and subalpine communities at lower elevations. A number of alpine specialists and endemic animals are found in this ecoregion, and the Alps are of great significance for humans as well. They serve as a water catchmentCatchment is the entire area of a hydrological drainage basin. area for half of Australia's human population and provide recreational activities in the numerous national parks.

Location and general description

The Australian Alps comprise the southeastern portion of the Great Dividing Range, or Eastern Highlands, a vast chain of high elevation areas that extend along the east coast of Australia from Tasmania to Cape York. The only area on mainland Australia to be glaciated, the Australian Alps extend for 500 kilometres over portions of two states and the Australian Capital Territory, from the Brindabella Ranges near Canberra nearly all the way to Melbourne. The uplift of the Alps began 50 to 60 million years ago, in a slow, gradual process. Kosciuszko, reaching 2228 meters (m), with a mean winter temperature of 1° to 2°C. On average, there are only ten frost-free days per year on Mount Kosciuszko. The maximum amount of rainfall for the Australian Alps is recorded here, approximately 3800 millimeters (mm) per annum. Precipitation decreases at lower elevations and in the east, where rain events are concentrated in the summer. Snow falls occasionally at lower elevations in the Alps, but does not remain on the surface for any appreciable length of time until altitudes increase. From 1400 m to 1800 m in elevation, snow may remain for one to four months, but above elevation 1800 m, snow-cover persists for over four months.

Biodiversity

While the Australian Alps do not reach high elevations by world standards, they are of special importance on a continental scale because they differ so dramatically from the rest of flat, arid, and drought-plagued Australia. The ancient, weathered Australian Alps are distinct from neighboring mountains: both the New Zealand Alps and the Tasmanian mountains have sharp, spiky peaks as a result of extensive glaciation and the alpine herbfield element is weakly developed in Tasmanian Mountains because snow cover there is short-lived. The Australian Alps are also unusual because they have well-formed soils all the way up to the highest summits, as a result of their extreme geological age.

Floristic features

The flora of the Australian Alps is unique as well. No fewer than thirty-six species of eucalyptus trees are found here, in a variety of climatic and edaphic conditions, including the Mountain Ash (Eucalyptus Regnans). Found only at lower elevations, this tree is distinguished as the tallest flowering plant on Earth.

Tall forests eventually yield dominance to snow gum communities that exhibit an understory of heathy shrubs. Snow gums include White Sallee (E. pauciflora) and Black Sallee (E. stellulata). Even hardy snow gums drop out past the treeline, which is from 1600 m to 1800 m depending on local conditions. Alpine vegetation is a mix of plants of lesser stature (no more than a metre in height) growing in heathland, grassland, herbfield and bog communities. Tall herbfields grow on well-developed humus soils, dominated by species of Compositae, Cyperaceae, Gramineae, Juncaceae, Ranunculaceae, and Umbelliferae. Coprosma spp. and Colobanthus spp. grow in fjeldmark communities. Shrub communities include Proteaceae, Myrtaceae, Rutaceae, Compositae, Leguminosae, and Podocarpaceae. The Mountain Plum-pine (Podocarpus lawrencei) is the only alpine conifer in mainland Australia.

Four main floristic zones are recognized for the Australian Alps: tableland, which extends up to 1100 m in elevation; montane (between 1100 m and 1400 m); subalpine (between 1400 and 1850 m); and alpine (normally above 1850 m). Vegetation in the tableland region was the first to be cleared, so that remnants are found along rivers, in low, grassy woodlands. Woodland species include Yellow Box (Eucalyptus melliodora) along with Acacia spp. such as Silver Wattle (A. dealbata) and Black Wattle (A. mearnsii). As elevation increases, the forest becomes wetter and denser. Species in these more mesichabitat characterized by moderate soil moisture zones include Bluegum Eucalyptus (Eucalpytus globulus), Narrow-leaved Peppermint (E. radiata), Broadleaf Peppermint Gum (E. dives), and Manna Gum (E. viminalis). At higher elevations, Mountain Ash (E. regnans) and Stringybark (E. delegatensis) grow in pure-species stands. The understory here is sparser than other montane forests because little light penetrates to the forest floor.

In total, more than 1400 higher plant species occur in the Australian Alps, and 66 of these species are endemic, with 26 species strictly endemic to alpine and subalpine regions. Although poorly known, the non-vascular flora also contributes a large number of species, with 20 percent of the total lichens known from Australia recorded from the Australian Alps. The flora of the Australian Alps show Gondwanan heritage in addition to many species derived from lowland elements. Eucalpytus and Acacia are two typically lowland Australian genera that have successfully invaded the montane and subalpine regions. The proportion of Gondwanan species increases with elevation. Regional endemism is high, with at least 10 percent of alpine plants around Mt. Kosciuszko endemic to that area. However, there are no genera endemic to the Australian mainland alpine regions, and endemism here is lower than in the Tasmanian Highlands.

Australian alpine plants display a number of adaptations to the cold climate, lengthy snow cover, and winter drought. Some species form floral buds during autumn and flower as soon as snow melts. Caltha introloba is an extreme example, flowering under the snow. A variety of other adaptations are similar to those found around the world in alpine climates: plants tend to be smaller and low to the ground, they grow quickly to take advantage of the short spring and summer seasons, and few plants produce seeds, instead growing from rhizomes, bulbs, or root nodes on other plants.

Faunal features

The Australian Alps boast a specialized fauna as well, with only a few species restricted to alpine areas above the snow line. There are a total of 342 vertebrate species that have beeen recorded in the ecoregion.

Mammals

The endangered Mountain Pygmy Possum (Burramys parvus) is a strict endemic found only at high elevations. The mountain Pygmy Possum is the sole marsupial to undertake long periods of hibernation, similar to placental mammals of the Northern Hemisphere. Other than the mountain pygmy possum, only four other small mammals are known to inhabit the alpine and subalpine areas of the Alps: the Broad-toothed Rat (Pseudomys fuscus), the Australian endemic Bush Rat (Rattus fuscipes), the Dusky Antechinus (Antechinus swainsonii), and the Agile Antechinus (A. agilis).  Other species considered near-endemic to this ecoregion include four skinks: Heatwole's Five-fingered Skink (Eulamprus heatwolei), Maccoy's Elf Skink (Nannoscincus maccoyi), Rawlingson's Window-eyed Skink (Pseudemoia rawlinsoni), and Spencer's Window-eyed Skink (P. spenceri).

Large mammals are more plentiful at lower elevations. Species seen here include Red-necked Wallaby (Macropus rufogriseus), Swamp Wallaby (Wallabia bicolor), common Coarse-haired Wombat (Vombatus ursinus), the rare Tiger Quoll (Dasyurus maculatus VU), and Australia's two monotremes, the Short-beaked Echidna (Tachyglossus aculeatus) and the Duck-billed Platypus (Ornithorhynchus anatinus), which occurs at elevations up to 1300 m.

Amphibians

caption Spotted Grass Frog, Australian endemic. Source: Nathan Ruser Nineteen anuranAn amphibian that has limbs but no tail (includes all frogs and toads) species are found in the ecoregion, many of which are endemic or near-endemic; notably, the Critically Endangered Corroboree Toadlet (Pseudophryne corroboree) is a strict endemic found only in high elevation areas of the ecoregion. The endemic and Critically Endangered Baw Baw Frog (Philoria frosti) is also an alpine specialist and is restricted to the Baw Baw Plateau in Victoria. Also found in the Australian Alps montane grasslands are: the Blue Mountains Treefrog (Litoria citropa), occurring along the coastal versanta region of land sloping in one general direction of the Alps and endemic to southeastern Australia; Blue-thighed Treefrog (Litoria raniformis), a taxon endemic to southeast Australia (especially the Murray River valley) and Tasmania; the Red Cryptic Treefrog (Litoria paraewingi), Spencer's treefrog (L. spenceri); the Near Threatened Bibron's Toadlet (Pseudophryne bibronii), a southeast Australia endemic; and Southern Toadlet (Pseudophryne dendyi). Other anurans occurring in the Australian Alps montane grasslands are: the Brown Treefrog (Litoria ewingii), most commonly found in flooded grasslands or other lentic Surface waters which are essentially still, such as lakes, ponds or puddlessurface waters; Verreaux's Treefrog (Litoria verreauxii); the Vulnerable Eastern Owl Frog (Heleioporus australiacus), endemic to southeastern Australia; the Vulnerable Green and golden Bell Frog (Litoria aurea), a southeastern Australia endemic that prefers freshwater emergent vegetation as habitat; Lesueur's Treefrog (Litoria lesueurii), a southeastern Australia endemic; Smooth Toadlet (Uperoleia laevigata), endemic to eastern Australia; Peron's Treefrog (Litoria peronii), a southeastern Australia endemic; Southern Toadlet (Pseudophryne semimarmorata), found only in Victoria, Tasmania and the Bass Strait Islands; Spotted Grass Frog (Limnodynastes tasmaniensis), found only in eastern Australia; Victoria Ground Froglet (Geocrinia victoriana), endemic to southeastern Victoria and the southeastern tip of New South Wales; and the Australian Green Treefrog (Litoria caerulea), found in both Australia and New Guinea.

Reptiles

Within the Australian Alps montane grasslands, there are a number of native reptiles, including: Australian Copperhead (Austrelaps superbus); Bearded Dragon (Pogona barbata), a near endemic, found only in eastern and southeastern Australia; black Rock Skink (Egernia saxatilis), a near endemic found only in southeast Australia; Blotched Blue-tongued Lizard (Tiliqua nigrolutea), an Australian endemic often found under surface litter;

Avifauna

A bird species which considered near-endemic to this ecoregion is the Rock Warbler (Origma solitaria). Some avifauna observedn at lower elevations in the Alps include the Superb Lyrebird (Menura novaehollandiae) and the Gang-gang Cockatoo (Callocephalon fimbriatum).  Approximately 60 avian species have been recorded in the ecoregion's alpine and subalpine zones, but none are restricted to these elevations. Birds that frequent high elevations include New Zealand Pipit (Anthus novaeseelandiae), Flame Robin (Petroica phoenicea), Little Raven (Corvus mellori), and Wedge-tailed Eagle (Aquila audax).

Invertebrates

The invertebrate fauna includes several alpine grasshoppers with unusual adaptations to the cold climate including the Southern Pyrgomorph (Monistria concinna) and Chameleon Grasshopper (Kosciuscola tristis). The Australian Alps are also known for the annual migration of Bogong Moths (Agrotis infusa) which aestivate in these alps each summer. These annual migrations provided a valuable food source for Maori Aborigines.

Current Status

Although a small area of the Australian continent (less than .3 percent), the Australian Alps receive 20 to 25 percent of the continent's total precipitation and provide water for half of Australia's population, as well as water for agricultural production and hydroelectricity generation. Due to its immense value as a water catchment area, the Australian Alps were first protected in the late 1800s and early 1900s when livestock grazing was restricted and then later, banned altogether. The majority of the Australian Alps montane grasslands ecoregion is state land today.

The Australian Alps are well conserved in a chain of alpine and sub-alpine protected areas covering 16,000 square kilometers (km2) across State and Territory borders. National parks include the Australian Capital Territory's (ACT's) Namadgi National Park, New South Wales's Kosciuszko, and Brindabella National Parks and Bimberi and Scabby Range Nature Reserves, and Victoria's Alpine and Snowy River National Parks and Avon Wilderness. Since 1986, these parks have been managed collectively, at the ecoregion level, as the result of a memorandum of understanding signed by the States and the ACT. This agreement is the only one of its kind in Australia. All ecosystems of the Australian Alps are well-represented in this system of protected areas.

Types and Severity of Threats

Although the majority of this ecoregion is protected in reserves and national parks, human use in protected areas may be destructive. The ever-increasing number of tourists results in trampling of delicate alpine flora, expansion of recreation infrastructure, particularly for skiing, and associated problems with waste disposal and pollution. A long history of domestic livestock grazing has left its mark on the Australian Alps, with damage from the early 1900s still apparent today. Grazing continues outside national parks and within some protected areas in Victoria as well, although not at the most fragile alpine and subalpine areas. Alpine plant endemics may be very localized and therefore especially vulnerable to extinction. Environmentally harmful agricultural practices and extensive commercial forestry continue outside protected areas and feral animals are a problem throughout the ecoregion. Finally, this cold, high-altitude ecosystem is threatened by climatic warming.

Justification of Ecoregion Delineation

The Australian Alps montane grasslands ecoregion includes the center of the 'Australian Alps' Centre of Plant Diversity and has complete correspondence with the 'Australian Alps' Interim Biogeographic Region of Australia (IBRA).

Further Reading

  • R.B. Good. 1995. Australian Alps. Pages 458 - 461 in S. D. Davis, V. H. Heywood and A. C. Hamilton. editors. Centres of Plant Diversity. Volume 2. Asia, Australasia, and the Pacific. WWF/IUCN, IUCN Publications Unit, Cambridge, UK. ISBN: 2831701988
  • C. Hilton-Taylor. 2000. 1998. The IUCN 2000 Red List of Threatened Species. IUCN, Gland, Switzerland and Cambridge, United Kingdom. ISBN: 2831705657
  • D. Mark. 1996. Australian Alps are ten years old. Australian Alps national parks. Viewed on August 29, 2001.
  • D. Slattery. 1998. The Australian Alps: Kosciuszko, Alpine, and Namadgi National Parks. University of New South Wales Press, Syndey, Australia. ISBN: 0868403199
  • R. Strahan. 1998. The mammals of Australia. Australian Museum/Reed New Holland. Syndey, Australia. ISBN: 1560986735
  • R. Thackway. and I. D. Cresswell. editors. 1995. An Interim Biogeographic Regionalisation for Australia: a framework for establishing the national system of reserves, Version 4.0. Australian Nature Conservation Agency, Canberra.
  • Williams, R. J. and A. B. Costin. 1994. Alpine and subalpine vegetation. Pages 467–500 in R. H. Groves, editor. Australian Vegetation. 2nd edition. Cambridge University Press, Cambridge, United Kingdom. ISBN: 0521424763

Disclaimer: This article contains some information that was originally published by the World Wildlife Fund. Topic editors and authors for the Encyclopedia of Earth have edited its content and added new information. The use of information from the World Wildlife Fund should not be construed as support for or endorsement by that organization for the new information added by EoE personnel.

 

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Citation

Hogan, C., & Fund, W. (2014). Australian Alps montane grasslands. Retrieved from http://www.eoearth.org/view/article/51cbed057896bb431f68f0e4

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