Australian Natural Resources Atlas

Natural Resource Topics

Biodiversity and Vegetation - Riverina

Riverina

Location Map

The Riverina Bioregion lies in the south west of NSW, extending into central-north Victoria. There are six subregions* in this bioregion; Lachlan (Riv1), Murrumbidgee (RIV2), Murray Fans (RIV3), Victorian Riverina (RIV4), Robinvale Plains (RIV5) and the Murray Scroll Belt (RIV6) subregions. The Riverina covers the alluvial fans of the Lachlan, Murrumbidgee and Murray Rivers west of the Great Dividing Range and extends down the Murray River.

This bioregion is dominated by river channels, floodplains, backplains, swamps, lakes and lunettes that are all of Quaternary age (less than 2 million years old). The region comprises three overlapping alluvial fans centred on the eastern half of the Murray Basin. Features of each fan differ slightly because of differences in discharge of the streams. The Lachlan fan is mainly clay because it is a smaller stream, it does not have competence to carry sand. The other two fans are similar except that the Murray is more confined and has more active anabranch channels where it is forced to flow around the obstacle of the Cadell fault near Echuca. At times of extreme flood flow water from the different streams can cross the fan surfaces and enter channels of another system.

Soils and vegetation reflect past patterns of sedimentation and today's flooding regime. Sandy soils are found in belts following the older stream channels, sometimes with local source bordering dunes adjacent to them. Texture contrast soils, often badly eroded, are found marginal to channels of all ages on former levees and terraces, and the plains are dominated by deposits of heavy, dark coloured clays. Many clay areas have gilgai micro-relief patterns, most crack extensively, and others are more or less permanently wet in swamplands.

Modern river channels support River Red Gum (Eucalyptus camaldulensis) and River Cooba (Acacia stenophylla) communities. Trees on the floodplains are mainly Black Box (Eucalyptus la.giflorens) and on higher, rarely flooded terraces yellow box (Eucalyptus melliodora) is found. Many plains are treeless and carry Oldman Saltbush (Atriplex nummularia), Bladder Saltbush (Atriplex vesicaria) and grasses. A formerly extensive community of myall (Acacia pendula) and old man saltbush on the backplains has almost vanished. Sandy soils on levees, old channels, dunes and lunettes have stands of white cypress pine (Callitris glaucophylla), sometimes with mallee and bluebush (Maireana sp.). Lake beds may be bare or covered by clumped lignum (Muehlenbeckia cunninghamii) with a fringe of black box. Swamps have wide margins of river red gum, black box and depending on water depth, also support common reed (Phragmites australis), cumbungi (Typha sp.), grasses and floating water plants.

As soil and water salinity increase downstream and saline clays become evident on lake floors, salt tolerant species such as samphire (Arthrocnemum sp.) become common.

(* 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 460,632 4.8
Eucalyptus woodlands 2,918,972 30.4
Acacia forest and woodlands 462,736 4.8
Callitris forest and woodlands 126,240 1.3
Casuarina forest and woodlands 176,268 1.8
Other forests and woodlands 97,992 1
Eucalyptus open woodlands 1,010,020 10.5
Acacia open woodlands 36 0
Mallee woodlands and shrublands 153,692 1.6
Low closed forest and closed shrublands 364,328 3.8
Acacia shrublands 11,896 .1
Other Shrublands 217,192 2.3
Tussock grasslands 567,232 5.9
Other grasslands, herblands, sedgelands and rushlands 656,068 6.8
Chenopod shrub, samphire shrub and forblands 2,218,876 23.1
Mangroves, tidal mudflat, samphire and bare areas, claypan, sand, rock, salt lakes, lagoons, lakes 120,232 1.3

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 4,580,904 47.8
Eucalyptus open forest 401,260 4.2
Eucalyptus woodlands 538,584 5.6
Acacia forest and woodlands 95,092 1
Callitris forest and woodlands 121,556 1.3
Casuarina forest and woodlands 130,800 1.4
Other forests and woodlands 66,316 .7
Eucalyptus open woodlands 97,168 1
Acacia open woodlands 36 0
Mallee woodlands and shrublands 54,344 .6
Low closed forest and closed shrublands 364,328 3.8
Acacia shrublands 7,208 .1
Other Shrublands 216,828 2.3
Tussock grasslands 334,748 3.5
Other grasslands, herblands, sedgelands and rushlands 650,020 6.8
Chenopod shrub, samphire shrub and forblands 1,810,048 18.9
Mangroves, tidal mudflat, samphire and bare areas, claypan, sand, rock, salt lakes, lagoons, lakes 120,232 1.3

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): 5,008,568 ha

Percent remaining native vegetation: 52.2%

Percent cleared/modified native vegetation: 47.8%

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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