South Eastern Highlands - biodiversity
Both soils and vegetation vary across the bioregion in relation to altitude, temperature and rainfall. Temperature affects the vertical distribution of species and can be observed in inverted sequences in frost hollows.
Diverse vegetation communities occur across the bioregion, including those consisting of yellow box (Eucalyptus melliodora), red box (Eucalyptus polyanthemos) and Blakely's red gum (Eucalyptus blakelyi), with areas of white box (Eucalyptus albens) occupying lower areas.
Red stringybark (Eucalyptus macrorhyncha), broad-leaved peppermint (Eucalyptus dives) and white gum (Eucalyptus rossii) associations dominate hills in the west of the bioregion. Brown barrel (Eucalyptus fastigata) communities are more common in the east. River oak (Casuarina cunninghamiana) is seen along main streams.
Grey gum (Eucalyptus punctata) and Blaxland's stringybark (Eucalyptus blaxlandii) are found on lower areas, and brown barrel, mountain gum (Eucalyptus dalrympleana), narrow-leaved peppermint (Eucalyptus radiata) and ribbon gum (Eucalyptus viminalis) occur on higher areas. Small areas of Argyle apple (Eucalyptus cinerea) can be found near Goulburn. Patches of snow gum (Eucalyptus pauciflora) occur in the highest places in cold air pockets.
High diversity swamps occur on the Boyd Plateau with Carex appressa and tea tree (Leptospermum myrtifolium) and sphagnum bogs in the streams. Dwarf casuarina (Casuarina nana), tea tree (Leptospermum lanigerum) and Calytrix tetragona heath are present on the dry aspects of ranges at the head of the Shoalhaven River.
Granite-derived soils support apple box (Eucalyptus bridgesiana), yellow box, some white box and red stringybark associations, with ribbon gums on the lower slopes and brown barrel occurring in the eastern parts of the bioregion. Rocky outcrops support patches of black cypress pine (Callitris endlicheri), whereas cold plateaus support open woodlands of snow gum and black sallee (Eucalyptus stellulata), with grasslands on the Monaro. River oak is widespread along streams.
Soils derived from Tertiary basalts support vegetation communities dominated by yellow box and Blakely's red gum, with red stringybark, white gum and broad-leaved peppermint across most of the Canobolas plateau. Ribbon gum and candle-bark gum (Eucalyptus rubida) associations dominate the lower slopes, while snow gum and mountain gum occupy cold patches and the high altitudes of Canobolas. Extensive grasslands are common on the driest plains of the Monaro, the characteristic species being snow grass (Poa sieberiana), spear grasses (Stipa scabra and Stipa variabilis), kangaroo grass (Themeda australis) and wallaby grass (Danthonia sp.). Clumps of snow gum can also be found among rocky outcrops.
Areas of sandy soils in the mid-Shoalhaven support woodlands of broad-leaved peppermint, snappy gum (Eucalyptus racemosa), forest oak (Allocasuarina torulosa), Banksia marginata and Banksia integrifolia.
There are 88 species listed in the schedules of the TSC Act in the South Eastern Highlands Bioregion (NSW NPWS 2001). Of these, 36 are listed as endangered, 50 are listed as vulnerable, and 2 species, Stemmacantha australis and Galium australe, are considered extinct.
Eucalyptus recurva is one threatened species that is also endemic to the bioregion. It has been described as the rarest of all eucalypts and is known from only 3 stands in the South Eastern Highlands (NSW NPWS 1999a). The plumed midge orchid (Genoplesium plumosum) is also endemic to the bioregion, known from only 6 colonies east of Marulan (NSW NPWS 1999b). Grevillea wilkinsonii, located east of Tumut, is also endemic to the bioregion.
Eighty-eight fauna species from the South Eastern Highlands Bioregion are listed in the schedules of the TSC Act (NSW NPWS 2001). Of these, 25 are listed as endangered and 63 are listed as vulnerable.
A noticeable decline in the numbers of the endangered regent honeyeater (Xanthomyza phrygia) in the bioregion is illustrative of a general decline in woodland bird species such as robins, treecreepers and many small honeyeaters (Australian Terrestrial Biodiversity Assessment 2002). These declines have been attributed to fragmentation of the landscape, which in this bioregion tends to occur at the edges of largely intact remnants.
This contrasts with substantial increases in noisy miner (Manorina melanocephala), Australian magpie (Gymnorhina tibicen) and grey butcherbird (Cracticus torquatus). These trends are consistent with those that might be expected in a fragmented landscape with a gradual decay in diversity in remnant patches, a decay that may only become evident over decades.
Over 7 per cent of all observations were of introduced taxa, with the bioregion being particularly important for the Eurasian tree sparrow (Passer montanus), common blackbird (Terdus merula), song thrush (Terdus philomelos) and common myna (Acridotheres tristis). The last species was recorded much more frequently in the second Atlas period than in the first. Although there was no decline in reporting rate apparent among those taxa that specialise in rainforest, temperate forest or temperate woodland, generalists did decrease, perhaps suggesting there has been little change in the high quality areas, but that gradual environmental degradation is occurring across the broader landscape.
There were no bioregionally significant wetlands recorded in the NSW part of the South Eastern Highlands Bioregion (Australian Terrestrial Biodiversity Assessment 2002). A number of wetlands in the bioregion are regarded as nationally important and listed in the Directory of Important Wetlands in Australia (ANCA 1996).
These wetlands are exposed to a variety of threats including exotic weed invasion, feral animals, grazing pressure, sedimentation and changed water regimes. Four-wheel driving and camping can also threaten the biodiversity of wetlands in the bioregion.
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Page last updated: 18 April 2016