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Southeastern Australia

Ancient rocks were slowly lifted over 50 million years to form the Australian Alps, the southeastern section of the Great Dividing Range. Extending over 500 km, largely through state-owned land, the Alps are an ecoregion like no other in low-lying, arid, drought-prone Australia. High mountains receive regular rainfall each year, 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 here, and the Alps are of vast significance for people as well. They serve as a water catchment area for half of Australia’s population and provide popular recreational activities in the numerous national parks.

  • Scientific Code
    (AA1001)
  • Ecoregion Category
    Australasia
  • Size
    4,600 square miles
  • Status
    Relatively Stable/Intact
  • Habitats

Description
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 km over 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. Substrate rocks vary in age from 500 to 20 million years old. Extensive weathering resulted in mountains with superficially similar shapes and heights, marked by undulating plateaus, long ridges, and narrow valleys.

Australia’s highest point is Mt. Kosciuszko, reaching 2,228 m, with a mean winter temperature of 1? to 2?C. On average, there are only 10 frost-free days per year on Mt. Kosciuszko. The maximum amount of rainfall for the Australian Alps is recorded here, approximately 3,800 mm per annum. Rainfall decreases at lower elevations and in the east where rain is concentrated in the summer. Snow falls occasionally at lower elevations in the Alps, but does not remain on the ground for any appreciable length of time until altitudes increase. From 1,400 m to 1,800 m in elevation, snow may remain for 1 to 4 months, but above 1,800 m snow lies on the ground for over 4 months (Slattery 1998).

Four main floristic zones are recognized for the Australian Alps: tableland, which goes up to 1,100 m in elevation; montane (between 1,100 m and 1,400 m); subalpine (between 1,400 m and 1,850 m); and alpine (normally above 1,850 m) (Good 1995). 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 yellow wattle (A. dealbata) and black wattle (A. mearnsii). As elevation increases, the forest becomes wetter and denser. Species here include blue gums (Eucalpytus globulus), peppermints (E. radiata, E. dives), and manna gums (E. viminalis). At higher elevations, mountain ash (E. regnans) and alpine ash (E. delegatensis) grow in pure stands. The understory here is sparser than other montane forests because little light penetrates to the forest floor.

Tall forests eventually give way to snow gums with an understory of heathy shrubs. Snow gums include white sallee (E. pauciflora) and black sallee (E. stellulatea). Even snow gums drop out past the treeline, which is from 1,600 m to 1,800 m depending on local conditions. Alpine vegetation is a mix of short plants no more than a meter in height growing in heathland, grassland, herbfield, and bog communities (Slattery 1998). 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 (Good 1995).

Biodiversity Features
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, dry, 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 age. The flora of the Australia 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, it is the tallest flowering plant in the world (Slattery 1998).

In total, more than 1,400 higher plant species are found in the Australian Alps and 66 species are endemic (Slattery 1998), with 26 species strictly endemic to alpine and subalpine regions (Good 1995). 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 (Good 1995). 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 (Willams and Costin 1994).

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 (Willams and Costin 1994). 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 (Slattery 1998).

The Australian Alps boast a specialized fauna as well, with only a few species restricted to alpine areas above the snow line. The endangered mountain pygmy possum (Burramys parvus) (Hilton-Taylor 2000) and the corroboree frog (Pseudophryne corroboree) are both strict endemics found only in high elevation areas. The mountain pygmy possum is the only marsupial to undergo long periods of hibernation, similar to placental mammals of the Northern Hemisphere (Strahan 1998). The endemic Baw Baw frog (Philoria frosti) is also an alpine specialist and is restricted to the Baw Baw Plateau in Victoria. Other species considered near-endemic to this ecoregion include the rock warbler (Origma solitaria), red cryptic treefrog (Litoria paraewingi), Spencer’s treefrog (L. spenceri), dendy toadlet (Pseudophryne dendyi), and four skinks, Heatwole’s five-fingered skink (Eulampus heatwolei), Maccoy’s elf skink (Nannoscincus maccoyi), Rawlingson’s (Pseudomoia rawlinsoni) and Spencer’s (P. spenceri) window-eyed skinks.

Large mammals are more plentiful at lower elevations. Species seen here include red-necked wallaby (Macropus rufogriseus), swamp wallaby (Wallabia bicolor), common wombat (Vombatus ursinus), the rare spotted-tail quoll (Dasyurus maculatus VU) (Hilton-Taylor 2000), and Australia’s two monotremes, the echidna (Tachyglossus aculeatus) and the platypus (Ornithorhynchus anatinus), which occurs up to 1,300 m. Birds seen at lower elevations in the Alps include the superb lyrebird (Menura novaehollandiae) and the gang gang cockatoo (Callocephalon fimbriatum). 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 (Mastacomys fuscus), the bush rat (Rattus fuscipes), the dusky antechinus (Antechinus swainsonii), and the agile antechinus (A. agilis). Approximately 60 bird species have been recorded in the alpine and subalpine zones, but none are restricted to these elevations. Birds that frequent high elevations include Richard’s pipit (Anthus novaeseelandiae), flame robin (Petroica phoenicea), little raven (Corvus mellori), and wedge-tailed eagle (Aquila audax). The invertebrate fauna includes several alpine grasshoppers with unusual adaptations to the cold climate including the mountain spotted grasshopper (Monistria concinna) and alpine thermocolor grasshopper (Kosciuscola tristis). The Australian Alps are also known for the annual migration of Bogong moths (Agrotis infusa) which aestivate in the mountains each summer. These annual migrations provided a valuable food source for Aborigines (Slattery 1998).

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 (Good 1995). 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 km2 across State and Territory borders. National parks include the 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 (Mark 1996). All ecosystems of the Australian Alps are well-represented in this system of protected areas (Good 1995, Thackway and Cresswell 1995).

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 (Good 1995). 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 global climatic warming (Slattery 1998).

Justification of Ecoregion Delineation
The Australian Alps Montane Grasslands ecoregion includes the center of the ‘Australian Alps’ Centre of Plant Diversity (Good 1995) and has complete correspondence with the ‘Australian Alps’ IBRA (Thackway and Cresswell 1995).

References
Good, R. B. 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.

Hilton-Taylor, C. 2000. 1998. The IUCN 2000 Red List of Threatened Species. IUCN, Gland, Switzerland and Cambridge, United Kingdom.

Mark, D. 1996. Australian Alps are ten years old. http://www.australianalps.environment.gov.au/aalc/mou10yrs.html. viewed on August 29, 2001.

Slattery, D. 1998. The Australian Alps: Kosciuszko, Alpine, and Namadgi National Parks. University of New South Wales Press, Syndey, Australia.

Strahan, R. 1998. The mammals of Australia. Australian Museum/Reed New Holland. Syndey, Australia.

Thackway, R. 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.

Prepared by: Miranda Mockrin
Reviewed by: Roger Kitching

 

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