Australian Natural Resources Atlas

Natural Resource Topics

Biodiversity and Vegetation - Murray Darling Depression

Murray Darling Depression

Location Map

The Murray Darling Depression bioregion lies in the south western corner of NSW and extends into Victoria and South Australia. There are six subregions* in the bioregion; South Olary Plain (MDD1), Murray Mallee (MDD2), Murray Lakes and Coorong (MDD3), Lowan Mallee (MDD4), Wimmera (MDD5) and the Darling Depression (MDD6).

The Murray Basin is a shallow crustal depression filled with marine and terrestrial sediments to a maximum depth of 600 m over the last 50-60 million years, as shallow seas have moved back and forth across the plains. Sandy surface sediments have been extensively reworked into dunes and sandplains. The Darling River and other streams have cut through the sands and constructed numerous overflow lakes such as the Sayers Lake system, and abandoned Pleistocene channel and basins of the Willandra Lakes complex. Saline groundwaters have formed salt basins in many places where the sandplain or dune topography intersects the water table.

Soils and vegetation differ according to the landform. On the dunefields red, brown and yellow calcareous sands occur with more clayey materials in the swales. Typically the dunes support diverse mallee communities with mixed shrubs and porcupine grass (Triodia pungens). Belah (Casuarina pauper and C. cristata), rosewood (Alectryon oleifolius) and variable spear grass (Stipa variabilis) occupy the swales. On sandplains the soil tends to be heavier with brown gradational or texture contrast profiles and mallee is only found on sandy rises. Typical sandplain species include rosewood, white cypress pine (Callitris glaucophylla), narrow-leaved hopbush (Dodonea viscosa), punty bush (Cassia eremophila), belah, copperburrs (Sclerolaena sp.), black bluebush (Maireana pyramidata) and variable spear grass.

Lakes and depressions all have clay floors, and vegetation relates to the presence or absence of salt and gypsum. Infrequently flooded freshwater lakes carry cane grass (Eragrostis australasica), lignum (Muehlenbeckia cunninghamii), and nitre goosefoot (Chenopodium nitrariaceum) with clumps of black box (Eucalyptus la.giflorens) on the margins. More saline lakes have grey cracking clays and carry chenopods. Salt lakes floors carry little vegetation.

Vegetation on lunettes varies. Clean sands often have white cypress pine, brown clayey sands support mallee with porcupine grass, and mixed sand and clay lunettes carry rosewood, belah, western pittosporum (Pittosporum phylliraeoides), narrow-leaf hopbush and bluebush. The largest rocky hills, Maccullochs Range, has mulga (Acacia aneura) dominated vegetation very similar to much of the Cobar Peneplain. Smaller hills have more of a mixture of local sandplain species and distant rocky slope species.

(* Subregional boundaries in NSW are an interim product in draft format for use exclusively in the Audit terrestrial biodiversity assessment.)

What major vegetation groups occurred in prior to European settlement?

Map: Pre-European Major Vegetation Groups in


Source:

Major vegetation groups V1.0 (1km), National Land and Water Resources Audit 2001. Data used are assumed to be correct from suppliers.

© Commonwealth of Australia 2001

The summary maps provide information on Australia's native vegetation collated within the National Vegetation Information System (NVIS) at July 2001 and with additional mapped information. The NVIS will be updated as vegetation mapping becomes available.

The map is a compilation of data collected at different scales by different organisations. Major Vegetation Groups were compiled by Environment Australia based on data collated by the Bureau of Rural Sciences and provided by Environment ACT, Department of Urban Services; NSW National Parks and Wildlife Service; NSW Royal Botanic Gardens; NSW State Forests; NT Department of Infrastructure, Planning and Environment; Queensland Herbarium, Environmental Protection Agency; SA Department for Environment and Heritage; Tasmanian Department of Primary Industries, Water and Environment; Flora Section, Department of Natural Resources and Environment; Agriculture Western Australia; Western Australia Department of Conservation and Land Management and Geoscience Australia, National Mapping Division.

Map: Extent of the National Vegetation Information System data

Extent of the National Vegetation Information System data

What was the area of major vegetation groups in prior to European settlement?

Table 1: Area of vegetation groups in prior to European settlement
Major Vegetation Group Area (ha) % total extent
Eucalyptus open forest 49,688 .3
Eucalyptus low open forest 77,616 .4
Eucalyptus woodlands 1,067,676 5.4
Acacia forest and woodlands 2,924 0
Callitris forest and woodlands 391,064 2
Casuarina forest and woodlands 2,970,948 15
Melaleuca forest and woodlands 284 0
Other forests and woodlands 326,540 1.7
Eucalyptus open woodlands 317,636 1.6
Mallee woodlands and shrublands 9,875,496 50
Low closed forest and closed shrublands 6,284 0
Acacia shrublands 934,236 4.7
Other Shrublands 686,372 3.5
Heath 263,256 1.3
Tussock grasslands 841,928 4.3
Hummock grasslands 168 0
Other grasslands, herblands, sedgelands and rushlands 244,088 1.2
Chenopod shrub, samphire shrub and forblands 1,492,456 7.6
Mangroves, tidal mudflat, samphire and bare areas, claypan, sand, rock, salt lakes, lagoons, lakes 187,700 1

What major vegetation groups occur in (circa 1997)?

Map: Dynamic Map of major vegetation groups (circa 1997) 1km


legend

Source:

Major vegetation groups V1.0 (1km), National Land and Water Resources Audit 2001. Data used are assumed to be correct from suppliers.

© Commonwealth of Australia 2001

The summary maps provide information on Australia's native vegetation collated within the National Vegetation Information System (NVIS) at July 2001 and with additional mapped information. The NVIS will be updated as vegetation mapping becomes available.

The map is a compilation of data collected at different scales by different organisations. Major Vegetation Groups were compiled by Environment Australia based on data collated by the Bureau of Rural Sciences and provided by Environment ACT, Department of Urban Services; NSW National Parks and Wildlife Service; NSW Royal Botanic Gardens; NSW State Forests; NT Department of Infrastructure, Planning and Environment; Queensland Herbarium, Environmental Protection Agency; SA Department for Environment and Heritage; Tasmanian Department of Primary Industries, Water and Environment; Flora Section, Department of Natural Resources and Environment; Agriculture Western Australia; Western Australia Department of Conservation and Land Management and Geoscience Australia, National Mapping Division.

Map: Extent of the National Vegetation Information System data

Extent of the National Vegetation Information System data

What is the area of major vegetation groups in (circa 1997)?

Table 2: Area of present vegetation groups in (circa 1997)
Major Vegetation Group Area (ha) % total extent
Cleared / modified native vegetation 7,450,212 37.7
Eucalyptus open forest 42,452 .2
Eucalyptus low open forest 77,616 .4
Eucalyptus woodlands 185,268 .9
Acacia forest and woodlands 2,924 0
Callitris forest and woodlands 390,164 2
Casuarina forest and woodlands 2,855,320 14.5
Melaleuca forest and woodlands 48 0
Other forests and woodlands 164,348 .8
Eucalyptus open woodlands 33,020 .2
Mallee woodlands and shrublands 5,138,312 26
Low closed forest and closed shrublands 6,280 0
Acacia shrublands 842,152 4.3
Other Shrublands 495,852 2.5
Heath 263,040 1.3
Tussock grasslands 119,456 .6
Hummock grasslands 168 0
Other grasslands, herblands, sedgelands and rushlands 238,312 1.2
Chenopod shrub, samphire shrub and forblands 1,272,404 6.4
Mangroves, tidal mudflat, samphire and bare areas, claypan, sand, rock, salt lakes, lagoons, lakes 171,788 .9

What is the extent of native vegetation in (circa 1997)?

Map: Dynamic Map of extent of native vegetation 1km by bioregion


Area of native vegetation remaining (ha): 12,298,924 ha

Percent remaining native vegetation: 62.3%

Percent cleared/modified native vegetation: 37.7%

What sources of information were used?

View the sources of information used to compile an Australian-wide map of pre-European and present native vegetation from the National Vegetation Information System and additional mapped data and the guidelines for the interpretation of vegetation mapping products.

Knowledge, data and information gaps

The compilation of native vegetation information has highlighted a number of gaps in our knowledge, the data and information about Australia's native vegetation.

References

View the references used in the Australian Native Vegetation Assessment 2001.

Partnerships

Australian Native Vegetation Assessment 2001 was facilitated and coordinated by the National Land and Water Resources Audit and prepared in partnership with State, Territory and Commonwealth agencies:

Australian Capital Territory

Department of Urban Services
www.urbanservices.act.gov.au

New South Wales

Department of Land and Water Conservation
www.dlwc.nsw.gov.au

NSW National Parks and Wildlife Service
www.npws.nsw.gov.au

NSW Botanic Gardens
www.rbgsyd.gov.au

Northern Territory

Department of Natural Resources, Environment and the Arts
www.nt.gov.au/nreta

Queensland

Environment Protection Agency
www.epa.qld.gov.au

South Australia

Planning SA
www.planning.sa.gov.au

Tasmania

Department of Primary Industries, Water and Environment
www.dpiwe.tas.gov.au

Victoria

Department of Sustainability and Environment
www.dse.vic.gov.au

Western Australia

Department of Conservation and Land Management
www.calm.wa.gov.au

Agriculture WA
www.agric.wa.gov.au

Commonwealth

Agriculture, Fisheries and Forestry - Australia
www.daff.gov.au

Australian Greenhouse Office
www.greenhouse.gov.au

Australian Department of Environment and Heritage
www.environment.gov.au

Further information

View the Australian Native Vegetation Assessment 2001 report.

The National Vegetation Information System Framework framework.

View Landscape Health in Australia 2001 report.

View the Australian Catchment, River and Estuary Assessment 2002.

View the Australian Terrestrial Biodiversity Assessment 2002.

View all Theme Reports from the National Land and Water Resources Audit.

Link to Atlas on-line mapping for maps of major vegetation groups and other natural resource data.

Link to data available for down load.

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