Bioregions of NSW

The 18 bioregions in NSW cover a wide diversity of landscapes.

NSW has a total area of 80,160,000 hectares (801,600 square kilometres). The Macintyre and Dumaresq rivers form part of the state boundary with Queensland, while the Murray River forms part of the southern NSW-Victorian boundary.

Eighteen of the 89 Australian bioregions are represented in NSW, but only 2 of these 18 bioregions, Cobar Peneplain and NSW North Coast, lie wholly within the NSW boundary. The other 16 are shared with the bordering states and territories: Australian Capital Territory, Victoria, South Australia, Northern Territory, Queensland and Jervis Bay Territory. The bioregion with the largest area in NSW is the Darling Riverine Plains bioregion.

Diversity of NSW landscapes

The diversity of NSW landscapes is evident in the wide range of the state's bioregions.

Western NSW

  • sandy deserts – Simpson-Strzelecki Dunefields, Channel Country, Murray Darling Depression
  • riverine plains – Riverina, Darling Riverine Plains
  • rocky ranges – Mulga Lands, Broken Hill Complex
  • rolling downs – Cobar Peneplain

Eastern NSW

  • lush rainforests – NSW North Coast, South East Corner, South East Queensland
  • rugged mountains – Sydney Basin, New England Tableland, Australian Alps, South Eastern Highlands
  • undulating ranges– Brigalow Belt South, Nandewar
  • fragile, wooded grasslands – NSW South Western Slopes

Protected areas

The 18 bioregions found in NSW vary considerably in the types of natural values they contain, and although they all have some representation in protected areas, there is great variation in the extent of each reserved.

The bioregion with the highest proportion reserved is the Australian Alps bioregion, with almost 90% protected. The reason for this high proportion is the prevalence of the alpine environs of Kosciuszko National Park, which dominate this bioregion.

Note: These figures were current in 2003 when The Bioregions of New South Wales was published. In 2020, the most poorly reserved bioregion in NSW was Broken Hill Complex, with almost 2% under reservation.

 

A summary of NSW

IBRA Bioregions in New South Wales (figures sourced from CAPAD 2018)

IBRA Region Name

1 IBRA Area in NSW (ha)

1 IBRA Area in Australia (ha)

% Percentage of bioregion in NSW

Australian Alps

464,034

1,232,981

37.64

Brigalow Belt South

5,623,054

27,219,776

20.66

Broken Hill Complex

3,766,741

5,635,422

66.84

Channel Country

2,335,604

30,409,437

7.68

Cobar Peneplain

7,385,346

7,385,346

100.00

Darling Riverine Plains

9,413,084

10,699,769

87.97

Murray Darling Depression

7,949,169

19,958,349

39.83

Mulga Lands

6,581,779

25,188,333

26.13

Nandewar

2,072,816

2,701,977

76.71

New England Tablelands

2,857,082

3,002,213

95.17

NSW North Coast

3,996,591

3,996,591

100.00

NSW South Western Slopes

8,114,379

8,681,126

93.47

Riverina

7,030,950

9,704,469

72.45

Simpson Strzelecki Dunefields

1,094,314

27,984,283

3.91

South East Corner

1,206,479

2,532,053

47.65

South Eastern Highlands

4,945,318

8,375,961

59.04

South Eastern Queensland

1,655,317

7,804,921

21.21

Sydney Basin

3,622,939

3,629,597

99.82

Total

80,115,007

 

1 Area is based on calculated GIS_AREA data. GIS_AREA is the area in hectares based on current spatial data and an Albers equal area projection for Australia.



NSW is described as being in the temperate zone although the climate undergoes large variations depending on proximity to the coast and mountains.

The temperature can be very high in the north-west of the State and very cold in the southern alpine regions, but the climate across NSW is generally mild.

Long-term median rainfall varies from a low of 200mm in the arid north-west of the State to a high of more than 1500mm along the north-east coast. This describes a general trend, with rainfall decreasing from the east to the west of NSW.

Topography, geomorphology and geomorphic history are usually linked to large, sometimes continental-scale, events. For this reason, the following summary of the major events in the formation of the landscape of NSW has been provided.

Major events in the formation of the landscape in NSW

NSW contains three main topographical divisions, as follows:

  • The Great Dividing Range comprising the Eastern Highlands, the Great Escarpment and the Western Slopes
  • The Far West Uplands
  • The Western Plains lying in between.

The eastern half of the State comprises thick sequences of sedimentary and metamorphic rocks that were intruded by granites and folded and faulted while the continent was part of Gondwana. Thick piles of less deformed sediments accumulated in the Murray, Sydney and Great Artesian Basins. Subsequently the whole east coast and Great Dividing Range was created by earth movement warping up a gentle arch along the eastern edge of the continent. This was associated with the opening of the Tasman Sea and Southern Ocean during the break-up of Gondwana.

This break-up was accompanied by volcanic activity in some places, and the short steep rivers flowing to the Pacific rapidly eroded the eastern slopes to produce the steep and rugged escarpments and deep gorges that run behind the coast. Geomorphically, the western slopes can be seen as a dissected ramp that links the uplifted highlands with the western plains. The Great Dividing Range is an elevated region of gently undulating country or broad plains, with the exception of areas of dramatic gorge country associated with the Great Escarpment.

The Western Plains are vast areas of shallow riverine sediment deposited by streams ancestral to the Murray-Murrumbidgee in the Riverina and the Darling and its tributaries in the Darling Riverine Plain. The plains slope gently west from the Great Dividing Range and lie against the eroded bedrock plateau and low ranges of the Cobar Block and the Barrier Ranges. The extensive sand sheets and dunefields of the Murray Basin cover bedrock in the south-western corner of the State.

The Western Plains experienced very little total uplift, but here and there in the Far West Uplands there has been some post-Miocene faulting.

Australia's native biodiversity is significant at a global scale and it is estimated that Australia supports more than one million species of plants and animals. As well as a high number of species, Australia also supports a great number and diversity of natural environments from the mountains to the coast, to woodlands, grasslands, rainforests and deserts.

About 82% of our mammals and 93% of our frogs are found nowhere else in the world. Over the last 200 years, the Australian environment has been modified dramatically. Australia has lost 75% of its rainforests and has the world's worst record of mammal extinctions. In NSW almost 1000 animal and plant species are at risk of extinction and are listed as threatened.

More information

Biodiversity and threatened species

Parks, reserves and protected areas

Aboriginal people have lived in the area known as NSW for at least 45,000 years and traditionally NSW is made up of about 70 different Aboriginal nations, each with their own language or language group.

European land settlement commenced in NSW in 1788 when Governor Arthur Phillip claimed possession of the land for a penal colony on behalf of the British Government.