Simpson-Strzelecki Dunefields - biodiversity
The sand dunes of the western half of Sturt National Park in the bioregion support a perennial woodland community dominated by Acacia ligulata, mulga, needlewood (Hakea leucoptera), whitewood (Atalaya hemiglauca) and beefwood (Grevillea striata). The woodland understorey is a shrubland consisting of species of Cassia, Eremophila and Dodonaea. Mitchell Grass also occurs on the dunes while temporary canegrass (Glyceria ramigera) - lignum (Muehlenbeckia cunninghamia) swamp communities occur between them.
The sand dunes and sandplains support sandhill wattle (Acacia ligulata), turpentine (Eremophila sturtii), scattered mulga (Acacia anuera), rosewood (Heterodendrum oleifolium), whitewood (Atalaya hemiglauca), canegrass (Eragrostis australasica), the occasional white pine (Callitris glaucophylla) and various cassia and eremophila species.
Lignum (Muehlenbeckia cunninghamia), black box (Eucalyptus largiflorens) and river red gum (Eucalyptus camaldulensis) grow along the creeks and on the margins of freshwater claypans. Many of the same species are found in the more saline clays of the Cobham land system along with prickly wattle (Acacia victoriae) and chenopods.
Bladder saltbush (Atriplex vesicaria), black bluebush (Maireana pyramidata), Mitchell grass (Astrebla sp.) and scattered mulga (Acacia anuera) are found on the tablelands and stony downs. Bimble box (Eucalyptus populnea), western bloodwood (Eucalyptus terminalis) and ironwood (Acacia excelsa) are present with denser mulga on the sands of the Bulloo Dunefield.
Seven species found in the bioregion are listed in the TSC Act 1995. Of these, five are listed as endangered and two are listed as vulnerable. A further three species, Glinus orygioides, Osteocarpum pentapterum and Senecio georgianus, which previously occurred in Sturt National Park, are now considered extinct in NSW (NSW NPWS 2001).
Forty-one fauna species found in the bioregion are listed in the schedules of the TSC Act. Of these, 12 are listed as endangered and 27 are listed as vulnerable. Two species, the pig-footed bandicoot (Chaeropus ecaudatus) and the burrowing bettong (Bettongia lesueur), are presumed extinct in the bioregion.
Although sand dunes are not generally home to a high diversity or number of birds, the bioregion supports a few distinct species. These include Eyrean grasswrens (Amytornis goyderi) which occur in cane grass on dunes (Australian Terrestrial Biodiversity Assessment 2002), as well as species characteristic of chenopod shrublands, many of which are threatened in other bioregions (Morton et al. 1995). In contrast to others, this bioregion shows little evidence of environmental change and supports few exotic bird species (Australian Terrestrial Biodiversity Assessment 2002).
Some waterbirds, such as the vulnerable painted snipe (Rostratula benghalensis), have been recorded here (Australian Terrestrial Biodiversity Assessment 2002), indicating a higher than average rainfall in this arid bioregion. During wet periods, many itinerant waterbirds breed on the ephemeral inter-dune swamps, although declines have been recorded in numbers of freshwater species and migratory waders (Australian Terrestrial Biodiversity Assessment 2002).
Feral animals threaten the biodiversity of the bioregion, with rabbits being particularly problematic.
Sturt National Park wetlands are a good example of canegrass claypans in dunefields and occur at the western end of Sturt National Park with mainly sparse vegetation dominated by canegrass (Eragrostis australasica), lignum (Muehlenbeckia spp.) and chenopods (Chenopodium spp.). Fort Grey basin and overflow swamps occur in this area and support large numbers of waterbirds (ANCA 1996). The wetlands are considered to be in good condition and are improving despite the presence of feral animals and weeds (Australian Terrestrial Biodiversity Assessment 2002).
The Salt Lake is a terminal salina, which is occasionally inundated for long periods. The water is saline, becoming more concentrated as evaporation occurs, and provides a representative example of a hypersaline lake. When full, more than 70,000 waterbirds have been recorded on the lake (Kingsford et al. 1994; cited in ANCA 1996) although the lake is usually dry and supports little vegetation. Submerged algae and sea tassel (Ruppia sp.) can be found when it is flooded (ANCA 1996).
Paldramata Lake is another significant wetland in the bioregion. In December 1989, the lake supported 4,200 waterbirds and in March 1993 over 2,000 waterbirds were recorded (Australian Terrestrial Biodiversity Assessment 2002). The most abundant species included Eurasian coot (Fulica atra), pink-eared duck (Malacorhynchus membranaceus) and hardhead (Aythya australis). Waterbirds recorded at the lake include the vulnerable freckled duck (Stictonetta naevosa) (Kingsford et al. 1994).
The lakes in the bioregion are considered to be in good condition (Australian Terrestrial Biodiversity Assessment 2002). Threats are present, however, and include impacts from grazing pressure, feral animals and exotic weeds.
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Page last updated: 27 February 2011