Nature conservation

Biodiversity Reform

Australian Alps - biodiversity

Plant communities

Both altitude and rainfall influence the vegetation communities of the Australian Alps Bioregion. There are four main physiographic elements to the bioregion, these being alpine, sub-alpine, montane and tableland areas (NSW NPWS 1988).

Alpine (areas above 1,850 m)

Tall alpine herbfield and heathland communities dominate the high alpine areas of the bioregion (Costin et al. 1979). Other communities such as sod tussock grassland, short alpine herbfield, feldmark (unique species or communities of prostrate plants that occur in remote alpine regions), bog and fen can occur where the effects of temperature, aspect, drainage and exposure impede the growth of tall herbfields (NSW NPWS 1988).

The highly organic soils of the alpine areas support about 200 plant species (Mitchell 2002). Brachycombe nivalis-Danthonia alpicola and Poa sp.-Celmisis sp. associations dominate the tall alpine herbfield communities (NSW NPWS 1988). Species such as the silver snow daisy (Celmisia sp.), ribbony grass (Chionochloa frigida), mountain celery (Aciphylla glacialis) and white purslane (Neopaxia australasica) also occur here (Mitchell 2002).

Tall herbfields on the flat or gentle sloping valley floors support sod tussock grasslands and several other inter-tussock herbs, especially Asteraceae species, including some that are rare and endemic (NSW NPWS 1988). Prickly snow grass (Poa costiniana) and alpine wallaby grass (Danthonia nudiflora) occur in tussock grasslands (Mitchell 2002).

Plantago sp. (Neopaxia australasica) associations dominate the short alpine herbfield communities that grow in areas below snowdrifts where cold snow water hampers the growth of the taller herbfield species (NSW NPWS 1988). Several other significant species comprise the community, including Caltha introloba, which has the unique characteristic of commencing flowering beneath the snow, and other low-growing species such as Dichosciadium ranunculaceum, Brachycome stolonifera, Diplaspis hydrocotyle and Parantennaria uniceps (NSW NPWS 1988).

Valleys and raised bogs support sphagnum, sedge (Carex gaudichaudiana) and heath (Epacris glacialis). The unique feldmark communities of the alpine region support ground-hugging alpine species such as coral heath (Epacris microphylla), eye-bright (Euphrasia collina), silver ewartia (Ewartia nubigena) and felted buttercup (Ranunculus muelleri), which are found on extremely stony and exposed snow patch sites (Mitchell 2002).

A high proportion of alpine species are endemic and all have restricted ranges (Mitchell 2002).

Subalpine (areas between 1,400 and 1,850 m)

Eucalyptus pauciflora-E. pauciflora ssp. niphophila (snow gum) woodland dominates the sub-alpine areas of the bioregion, interspersed with extensive open grasslands and heath (Mitchell 2002). About 80 per cent of these woodlands have regenerated following severe bushfires over the last 50 years. A dense understorey of shrubs lies beneath the tree canopy, including Oxylobium ellipticum-Podocarpus lawrencii associations, with Bossiaea foliosa species (NSW NPWS 1988). These species form both the tall, shrubby understorey and, on exposed sites, dense heaths. A short heath of Kunzea muelleri-Epacris spp. grows in place of the tall heath on sites with poor drainage (NSW NPWS 1988).

Cold air drainage into the valleys, known as frost hollows, prevents trees growing in the sod tussock grasslands on the valley floors where Poa sp.-Danthonia nudiflora associations dominate (NSW NPWS 1988). Bogs and fens develop here in the valleys where the water tables rise up to or above the ground. Fen communities are dominated by Carex species and are limited by permanent watercourses or are part of bog communities, which are usually defined by Sphagnum species.

Montane (areas between 1,100 and 1,400 m)

The montane areas of the bioregion are dominated by forests and woodlands of stringybarks and gums which grow in sequence from swamp gums (Eucalyptus ovata), peppermint forests (narrow-leaved peppermint E. radiata) and blue gums (E. globulus ssp. bicostata) on the lower slopes, to mountain gum (E. dalrympleana), candlebark (E. rubida), ribbon gum (E. viminalis) and alpine ash (E. delegatensis) which eventually give way with altitude to pure stands of snow gum which grow directly below the treeline (Costin et al. 1979).

These montane forests and woodlands are mainly associated with snow gums, including E. pauciflora, E. dalrympleana, E. rubida, E. viminalis, and E. stellulata. E. delegatensis dominates the wetter areas with southerly and southeasterly aspects (NSW NPWS 1988). This wet sclerophyll forest has an understorey of species, including Bossiaea foliosa, that are similar to those in sub-alpine areas. E. globulus ssp. bicostata, E. glaucescens and E. fastigata occur in more sheltered areas as dominant trees or are co-dominant with other species or associations.

Isolated occurrences have been recorded for E. kybeanensis, E. chapmaniana, Acacia dallachiana and Atherosperma moschatum (NSW NPWS 1988). The more westerly aspects comprise narrow-leaved peppermint (E. radiata)-ribbon gum (E. viminalis)-candlebark (E. rubida) associations as dominants. Sheltered areas with easterly aspects are dominated by brown barrel (E. fastigata)-alpine ash (E. delegatensis) associations (NSW NPWS 1988) and black sallee (E. stellulata) lines the streams on the high plains (Mitchell 2002).

High plains grasslands are dominated by snow grass (Poa sp.) with patches of heath that include leafy bossiaea (Bossiaea foliosa), yellow kunzea (Kunzea muelleri), royal grevillea (Grevillea victoriae), alpine pepper (Tasmannia xerophila), small-fruit hakea (Hakea microcarpa) and mountain shaggy pea (Oxylobium alpestre). Sphagnum bogs (Sphagnum cristatum) with candle heath (Richea continentis) and swamp heath (Epacris paludosa) occur at the head of most creeks (Mitchell 2002).

Tableland (areas below 1,100 m)

Savannah woodlands are common in the tableland areas of the Australian Alps Bioregion and are dominated by E. melliodora-E. blakelyi and E. viminalis-E. rubida associations (NSW NPWS 1988). Mixed eucalypt forest is found at the lowest elevations (Mitchell 2002). On dry aspects or well-drained granites, the forests are typified by red stringybark (E. macrorhyncha), white gum (E. rossii), broad-leaved peppermint (E. dives), candlebark (E. rubida), and brittle gum (E. mannifera) with a diverse understorey of shrubs and grasses (Mitchell 2002).

On sedimentary rocks or in moist aspects and higher rainfall areas, more common tree species include alpine ash (E. delegatensis), mountain gum (E. dalrympleana), narrow-leaved peppermint (E. radiata), manna gum (E. viminalis) and brown barrel (E. fastigata) (Mitchell 2002). The peppermints (broad-leaved E. dives and narrow-leaved E. radiata) are dominant on exposed sites, while E. dalrympleana, E. pauciflora and E. viminalis occur at higher altitudes in moister areas (NSW NPWS 1988). Moist gullies support soft tree ferns (Dicksonia antartica), blackwood (Acacia melanoxylon), southern sassafras (Atherosperma moschatum) and hazel pomaderris (Pomaderris aspera).

Significant flora

Within the alpine areas of the bioregion there are about 30 exclusively alpine species and 21 locally endemic species (NSW NPWS 1988). Furthermore, 61 species are singularly representative of their genus and 20 are singular representatives of their family that grows above the treeline.

Feldmarks cover less than one per cent of alpine areas (NSW NPWS 1988). Cold feldmarks are found in sheltered areas of high mountain saddles, while wind-swept feldmarks occur in more exposed locations at higher altitudes on the windward side of saddles. Feldmark communities support Coprosma pumila-Colobanthus sp. and Epacris microphylla-Chionohebe densifolia associations.

Significant fauna

The record of species such as the tiger quoll (Dasyurus maculatus) and koala (Phascolarctos cinereus) in Kosciuszko National Park is significant, because these species are not recorded frequently in NSW and their ranges in the park appear to be diminishing (NSW NPWS 1988). The broad-toothed rat (Mastacomys fuscus) was once widespread throughout southeastern Australia and is now restricted to certain areas of the Australian Alps Bioregion within Kosciuszko National Park (NSW NPWS 1988).

The eastern or Tasmanian bettong (Bettongia gaimardi) has been recorded in the Australian Alps Bioregion since European settlement although it has not been seen for many years and is now considered to be extinct on the Australian mainland. Like the bettong, the eastern quoll (Dasyurus viverrinus) has been recorded in the bioregion and unconfirmed reports were received occasionally until 1970, the date of the last report (NSW NPWS 1988).

Of the 202 bird species recorded in Kosciuszko National Park, two are locally extinct. The orange-bellied parrot (Neophema chrysogaster), which is now extinct in the bioregion, was known from a single specimen collected in Thredbo in 1917. The Australian bustard (Ardeotis australis) is also locally extinct, having been recorded in the park in 1896, and it is now known only from the far northwest of NSW (NSW NPWS 1988)

Other species have not been recorded in Kosciuszko National Park for many years. These include the masked owl (Tyto novaehollandiae, last recorded in 1896), the banded plover (Vanellus tricolour, in 1946) and the southern whiteface (Aphelocephala leucopsis, also in 1946) although they may still be present in small numbers (NSW NPWS 1988). Some species regarded as uncommon or scarce in NSW have been seen in the Park. These include the pink robin (Petroica rodinogaster), the black-eared cuckoo (Chrysocossyx osculans) and the blue-winged parrot (Neophema chrysostoma).

The variety of altitudes in the bioregion gives rise to altitudinal migration throughout the year. Birds such as the pipit (Anthus novaeseelandiae), nankeen kestrel (Falco cenchroides) and the Australian magpie (Gymnorhina tibicen) occupy the treeless alpine areas during summer, retreating to lower elevations in autumn. Some species, however, are not discouraged by the harsh winter climate of the higher altitudes; the gang-gang cockatoo (Callocephalon fimbriatum) inhabits the sub-alpine snow gums even in winter (NSW NPWS 1988).

As no Australian bird species are truly alpine, and none is endemic to the bioregion, the Australian Alps Bioregion has a low bird species diversity, the frequently sighted species generally living in the woodlands adjacent to the alpine grass and herbfields. Declines in species such as the gang-gang cockatoo and the flame robin, which occupy higher altitudes, may reflect the warmer weather of the last few decades although this cannot be confirmed without further studies. However this loss of upland species and a contraction of grassland is a likely future scenario if the trend towards higher temperatures continues.

Reptiles and frogs in the Australian Alps Bioregion display a surprising degree of diversity considering its harsh climate. There are reported to be 31 species of reptiles in Kosciuszko National Park. One of these, the alpine water skink (Sphenomorhus koscuiskoi), is restricted to habitats higher than 1,000 m in the southern tablelands and so its range is almost entirely restricted to the Park. There are 7 snakes known to occur in the Park although some species are rarely seen.

Of the lizards known to occur in the Park, some have not been recorded for many years (NSW NPWS 1988). There are reported to be 11 species of frogs in the Park, including the unusual corroboree frog (Pseudophryne corroboree), which can be identified by its distinctive black and yellow markings and is found in the sphagnum bogs of the alpine areas. The species is known to have 2 forms, a northern form, which occurs mainly in the ACT, and a southern form, which may be endemic to Kosciuszko National Park.

The rivers in the east of Kosciuszko National Park support species of migratory eels and two freshwater fish species from the galaxiid family, while species of perch, gudgeon, Murray cod and possibly galaxiids occur in the western rivers. Brown, rainbow and brook trout, as well as Atlantic salmon and redfin, have been introduced to the rivers in the bioregion (NSW NPWS 1988).

Significant wetlands

All of the wetlands of the bioregion are considered to be in near pristine condition despite problems with feral animals and impacts from tourism activities. No decline in status is evident, largely because they have been protected within Kosciuszko National Park.

Blue Lake is the only dimictic lake in mainland Australia, meaning its thermal layers are mixed completely twice each year. Such glacial lakes are significant because they are low in nutrients and are completely iced over for half the year, providing key habitat for species of invertebrate fauna not found elsewhere (ANCA 1996).

Kosciuszko alpine fens, bogs and lakes are the only alpine wetlands in NSW. Alpine plant succession in the area has been studied since the exclusion of cattle grazing in 1958 (ANCA 1996). The sphagnum bogs of these wetlands are probably suitable breeding habitat for the southern corroboree frog.

Rennex Gap lies at the inside edge of the sub-alpine snow gum woodland of Mt Kosciuszko and is considered to be a good example of upland peatland. The area provides fire and vegetation histories close to the Pleistocene ice cap (ANCA 1996). Snowgum Flat, like Rennex Gap, is also a good example of upland peatland and is representative of low altitude sub-alpine bogs characteristic of the southern end of Kosciuszko National Park (ANCA 1996).

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Page last updated: 18 April 2016