1.1.7.1 Ecological systems


The Galilee subregion includes a very high level of ecological spatial variability and turnover (gamma and delta diversity) as a consequence of its large area (248,000 km2) which includes important interactions between the following large-scale environmental factors:

  • the large variety of surface geological types and soil types along gradients from the top of the Great Dividing Range towards the Gulf of Carpentaria (to the north), towards the Great Barrier Reef (to the east), towards the Darling River (to the south) and towards Kati Thanga – Lake Eyre (to the south-west) (see sections 1.1.3 and 1.1.2.1.2)
  • the rainfall and temperature gradients induced by orographic effects over the Great Dividing Range
  • the rainfall and temperature gradients from near-coast (subtropical, higher rainfall, temperature range modulated by oceanic effects) to far inland (arid, low rainfall, more extreme temperature ranges on both seasonal and daily bases) (see Section 1.1.2.3)
  • the gradient in seasonality of rainfall across the latitudinal range from 19° South (strongly summer dominated) to 29° South (less predictable and only weakly summer dominated)
  • the strong influences of surface water redistribution after rain, even in landscapes with modest degrees of topographic relief, and of access to near-surface groundwater, as is typical of Australian arid and semi-arid landscapes (e.g. Stafford Smith and Morton, 1990)
  • the variety of biogeographic influences arising within the eight main river basins that drain to the north, east, south and south-west, and thus each interact with the diverse biota in other surrounding regions and subregions (see Section 1.1.5).

As an indication of the variability within the Galilee subregion, 31 Interim Biogeographic Regional Assessment (IBRA) subregions (Figure 51) and 46 major vegetation subgroups defined in the National Vegetation Information System (NVIS) v4.1 classification (Figure 52, Table 8) are represented. About half of the subregion is dominated by subtropical savannah vegetation communities, where mean annual rainfall is in the range 600 to 800 mm. Mitchell grass (Astrebla) tussock grasslands and Eucalyptus open woodlands with a grassy understorey are the most common NVIS major subgroups in this zone. The remaining half is dominated by semi-arid vegetation communities, where mean annual rainfall is in the range 300 to 600 mm, of which Mulga open woodlands are the most common NVIS major subgroup.

Wetlands and springs listed in A directory of important wetlands in Australia (DIWA; Department of the Environment, 2014c) occupy 0.3% of the area of the subregion and include representation of 21 NVIS v4.1 major vegetation subgroups (Table 8). Nationally mapped riverine floodplains that are also potentially water dependent, at least in part on a seasonal or multi-year basis through flooding and/or elevated watertable, occupy a further 15.5% and include all 46 vegetation subgroups found within the Galilee subregion (Table 8 and Figure 53). For both the DIWA wetlands and the riverine floodplains, the mapped areas include areas of vegetation subgroups that have low likelihood of being dependent on water in excess of local incident rainfall and sourced from subterranean and/or surface water flows (hereafter termed water-dependent as per Methodology for bioregional assessments of the impacts of coal seam gas and coal mining development on water resources ; Barrett et al., 2013)). The inclusion of non-water-dependent ecosystems in DIWA wetlands and riverine floodplains is due to the coarse resolution of existing map polygons which include some areas that are sufficiently distant from water bodies and/or sit well above ecologically accessible groundwater. The remaining 84.2% of the area is of terrestrial vegetation subgroups with limited likelihood of being water-dependent.

Land use includes 21 of the 37 Australian Land Use and Management (ALUM) classification scheme secondary classes, but their occurrence is highly non-uniform (see Figure 10 in Section 1.1.2). Pastoral cattle grazing of native and semi-natural pasture, on both freehold and leasehold lands (Figure 54), is by far the greatest land use (95.4% of the area, approximately two-thirds on leasehold), which is consistent with the predominance of subtropical savannah and semi-arid climates, landscapes and vegetation community types. Conservation is the principal land use for 3.0% of the area, which is below the national average of 8.6% in the Australian National Reserve System (excluding lands of private and Indigenous landholders who have conservation amongst multiple land use objectives) and below the Queensland average of 7.5% (Department of the Environment, 2012).

Figure 51

Figure 51 Interim Biogeographic Regionalisation for Australia (IBRA) subregions within the Galilee subregion

Source data: IBRA version 7 (2012) ©Commonwealth of Australia 2012 Sub IBRA boundaries produced by ERIN for the National Reserve Systems Section, Australian Government Department of Sustainability, Environment, Water, Population and Communities, Canberra, May 2012

Figure 52

Figure 52 National Vegetation Information System (NVIS) major vegetation subgroups

Source data: NVIS v4.1 major vegetation subgroups, ERIN Vegetation Team, Department of the Environment, Canberra, 2013

Table 8 National Vegetation Information System (NVIS v4.1) major vegetation subgroups in the Galilee subregion

DIWA is A directory of important wetlands in Australia (Department of the Environment, 2014c)


Vegetation subgroups (in descending order of area)

Area of subgroup in subregion (ha)

Area of subgroup in subregion, as percentage of total area of subgroups (%)

Area of DIWA wetlands in the subgroup

(ha)

Area of DIWA wetlands in the subgroup, as percentage of total area of subgroups (%)

Area of watercourses and floodplains in subgroup (ha)

Area of watercourses and floodplains in subgroup, as percentage of total area of subgroups (%)

Mitchell grass (Astrebla) tussock grasslands

8,161,495

32.89%

0

0.00%

1,408,258

5.68%

Eucalyptus open woodlands with a grassy understorey

4,094,284

16.50%

2,830

0.01%

637,173

2.57%

Cleared, non-native vegetation

3,991,376

16.08%

1,421

0.01%

339,685

1.37%

Acacia (+/- low) open woodlands and sparse shrublands +/- tussock grass

1,270,217

5.12%

4,408

0.02%

157,386

0.63%

Mulga (Acacia aneura) open woodlands and sparse shrublands +/- tussock grass

832,756

3.36%

3,169

0.01%

37,343

0.15%

Eucalyptus woodlands with a tussock grass understorey

804,423

3.24%

645

<0.01%

130,518

0.53%

Other Acacia forests and woodlands

688,740

2.78%

2,164

0.01%

79,814

0.32%

Acacia (+/- low) open woodlands and sparse shrublands with hummock grass

456,367

1.84%

0

0.00%

6,425

0.03%

Eucalyptus low open woodlands with hummock grass

441,267

1.78%

131

<0.01%

20,299

0.08%

Acacia (+/- low) open woodlands and sparse shrublands with a shrubby understorey

437,307

1.76%

0

0.00%

12,728

0.05%

Wet tussock grassland with herbs, sedges or rushes, herblands or ferns

393,972

1.59%

16,479

0.07%

296,017

1.19%

Mulga (Acacia aneura) woodlands and shrublands +/- tussock grass +/- forbs

387,675

1.56%

1,523

0.01%

8,778

0.04%

Other tussock grasslands

386,968

1.56%

3,210

0.01%

136,241

0.55%

Eucalyptus low open woodlands with tussock grass

358,370

1.44%

1,884

0.01%

177,395

0.71%

Eucalyptus woodlands with a shrubby understorey

264,839

1.07%

0

0.00%

7,703

0.03%

Blue grass (Dicanthium) and tall bunch grass (Chrysopogon) tussock grasslands

242,495

0.98%

0

0.00%

116,054

0.47%

Brigalow (Acacia harpophylla) forests and woodlands

237,637

0.96%

2

<0.01%

9,288

0.04%

Other open woodlands

212,029

0.85%

0

0.00%

19,337

0.08%

Other Acacia tall open shrublands and shrublands

201,233

0.81%

0

0.00%

20,980

0.08%

Other forests and woodlands

146,973

0.59%

0

0.00%

39,748

0.16%

Callitris forests and woodlands

126,239

0.51%

0

0.00%

8,596

0.03%

Mixed chenopod, samphire +/- forbs

105,319

0.42%

8,178

0.03%

51,568

0.21%

Mallee with hummock grass

92,570

0.37%

0

0.00%

6,086

0.02%

Eucalyptus open woodlands with shrubby understorey

85,648

0.35%

0

0.00%

44,480

0.18%

Hummock grasslands

69,516

0.28%

28

<0.01%

3,104

0.01%

Eucalyptus open forests with a grassy understorey

62,810

0.25%

0

0.00%

140

<0.01%

Melaleuca shrublands and open shrublands

40,583

0.16%

0

0.00%

405

<0.01%

Acacia (+/- low) open woodlands and sparse shrublands with chenopods

40,205

0.16%

0

<0.01%

3,161

0.01%

Freshwater, dams, lakes, lagoons or aquatic plants

25,604

0.10%

18,083

0.07%

22,371

0.09%

Melaleuca open forests and woodlands

24,111

0.10%

0

0.00%

1,860

0.01%

Eucalyptus low open woodlands with a shrubby understorey

23,785

0.10%

0

0.00%

659

0.00%

Eucalyptus open forests with a shrubby understorey

20,133

0.08%

0

0.00%

10,795

0.04%

Mulga (Acacia aneura) woodlands and shrublands with hummock grass

17,481

0.07%

0

0.00%

170

<0.01%

Other shrublands

15,478

0.06%

0

0.00%

2,118

0.01%

Naturally bare, sand, rock, claypan, mudflat

12,422

0.05%

0

0.00%

2,975

0.01%

Dry rainforest or vine thickets

10,739

0.04%

0

0.00%

0

<0.01%

Saltbush and/or Bluebush shrublands

10,680

0.04%

0.01

<0.01%

9,089

0.04%

Lignum shrublands and wetlands

5,697

0.02%

0

0.00%

3,545

0.01%

Mulga (Acacia aneura) open woodlands and sparse shrublands with hummock grass

5,019

0.02%

0

0.00%

7

<0.01%

Sedgelands, rushs or reeds

4,907

0.02%

242

<0.01%

2,484

0.01%

Melaleuca open woodlands

2,568

0.01%

11

<0.01%

559

<0.01%

Casuarina and Allocasuarina forests and woodlands

1,079

<0.01%

11

<0.01%

196

<0.01%

Callitris open woodlands

986

<0.01%

0

<0.01%

36

<0.01%

Eucalyptus woodlands with a hummock grass understorey

292

<0.01%

0

<0.01%

3

<0.01%

Casuarina and Allocasuarina open woodlands with a tussock grass understorey

211

<0.01%

191

<0.01%

197

<0.01%

Eucalyptus woodlands with ferns, herbs, sedges, rushes or wet tussock grassland

17

<0.01%

0

<0.01%

17

<0.01%

Total

24,814,524

100.00%

64,610

0.26%

3,835,791

15.46%

Source data: (1) NVIS v4.1 major vegetation subgroups, ERIN Vegetation Team, Department of the Environment, Canberra, 2013. (2) A directory of important wetlands in Australia, third edition (Environment Australia, 2001), with additions for wetlands listed after 2001 (last update 23 March 2010). (3) Watercourses and floodplains from the combination of all other datasets listed as sources for Figure 3

Figure 53

Figure 53 Conservation areas (including wetlands listed in A directory of important wetlands in Australia), springs and riverine floodplains with potential for water dependence

Source data: (1) A directory of important wetlands in Australia, third edition (Environment Australia, 2001), with additions for wetlands listed after 2001 (last update 23 March 2010). (2) Collaborative Australian Protected Areas Database (CAPAD, 2010). Australian Department of Sustainability, Environment, Water, Population and Communities. (3) Environmental Resources Information Network (ERIN). Australian Department of Environment. (4) Catchment Scale Land Use Mapping for Australia, Update November 2012 (CLUM Update 11/12). Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES). (5) National Vegetation Information System (NVIS v4.1) major vegetation subgroups. Department of Environment. (6) GEODATA TOPO 250K Series 3 Topographic Data. Geoscience Australia

Table 9 Australian Land Use and Management (ALUM) Classification (version 7) land use classes in the Galilee subregion


ALUM secondary land use class

Area in subregion (ha)

Area in subregion, as percentage of total (%)

Grazing natural vegetation

23,662,649

95.36%

Nature conservation

750,647

3.03%

Other minimal use

231,263

0.93%

Production forestry

84,751

0.34%

Marsh/wetland

54,977

0.22%

Cropping

10,081

0.04%

Services

5,477

0.02%

Lake

4,232

0.02%

Reservoir/dam

2,711

0.01%

Residential

2,452

0.01%

River

1,375

0.01%

Transport and communication

1,175

<0.01%

Irrigated cropping

826

<0.01%

Mining

530

<0.01%

Manufacturing and industrial

476

<0.01%

Intensive animal husbandry

432

<0.01%

Managed resource protection

297

<0.01%

Irrigated perennial horticulture

85

<0.01%

Waste treatment and disposal

78

<0.01%

Utilities

10

<0.01%

Total

24,814,524

Source data: Catchment Scale Land Use Mapping for Australia Update November 2012 (ALUM Update 11/12) dataset. Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES)

Figure 54

Figure 54 Land tenure as at 2009

Source data: Queensland Digital Cadaster Database (DCDB). Supplied by Queensland Department of Natural Resources and Mines, download date 12/01/2014. Protected Area data are from Queensland Protected Areas Database 5 December 2012. Supplied by the Queensland Department of National Parks, Recreation, Sport and Racing

Last updated:
3 January 2019