The Brigalow Belt is a wide band of acacia-wooded grassland that runs between tropical rainforest of the coast and the semi-arid interior of Queensland and northern New South Wales, Australia. The Interim Biogeographic Regionalisation for Australia (IBRA) divides the Brigalow Belt into two IBRA regions, or bioregions, Brigalow Belt North (BBN) and Brigalow Belt South (BBS). The North and South Brigalow Belt are two of the 85 bioregions across Australia and the 15 bioregions in Queensland. Together they form most of the Brigalow tropical savanna ecoregion.
Location and description The Northern Brigalow Belt covers just over and runs from just north of Townsville to Emerald and Rockhampton on the Tropic of Capricorn, while the Southern Brigalow Belt runs from there down to the Queensland/New South Wales border and a little beyond, until the habitat becomes the eucalyptus dominated Eastern Australian temperate forests.
This large, complex strip of countryside covers an area of undulating to rugged slopes, consisting of ranges as well as plains of ancient sand and clay deposits, basalt and alluvium. The Northern Brigalow Belt includes the coal producing Bowen Basin, with the nearby Drummond Basin and the fertile Peak Downs areas. The southern belt, which begins with the sandstone gorges of the Carnarvon Range of the Great Dividing Range, runs into the huge Great Artesian Basin. The south-west side includes the farming area of Darling Downs.
A number of important rivers drain the Brigalow Belt. The large Fitzroy River system and the Belyando and Burdekin rivers near the tropics all drain eastwards, while the south-western areas drain westwards into the Murray–Darling basin via the Maranoa, Warrego and Condamine Rivers.
In the north, there are tropical summer rains and warm weather all year round, while in the south the winter is slightly cooler and there is more rainfall outside of the summer months. Throughout the belt, the interior, with less than 500 mm of rainfall per year, is drier than the coast, which may have 750 mm or more.
Flora
The characteristic plant communities are woodlands of highly water stress tolerant brigalow (Acacia harpophylla), a slender acacia tree which thrives on the clay soil and once covered much of the area especially the fertile lowlands. Most of the brigalow has been cleared to make agricultural land, but the Queensland Bottle Tree is often left uncleared due to its leaves being fodder for cattle. Eucalypt woodlands of silver-leaved and narrow-leaved ironbarks, poplar box and other boxes, blackbutt and coolibah are also intact primarily on the higher slopes.Young, P.A.R., B.A. Wilson, J.C. McCosker, R.J. Fensham, G. Morgan, and P. M. Taylor. 1999. Brigalow Belt. Pages 11/1-11/81 in P. Sattler and R. Williams, editors. The Conservation Status of Queensland's Bioregional Ecosystems. Environmental Protection Agency, Brisbane, AustraliaThackway, R., and I.D. Creswell. 1995. An Interim Biogeographic Regionalisation for Australia: A framework for establishing a national system of reserves, Version 4. Australian Nature Conservation Agency, Canberra, Australia.Arnold, S., P. Audet, D. Doley, and T. Baumgartl. 2013. Hydropedology and ecohydrology of the Brigalow Belt, Australia: opportunities for ecosystem rehabilitation in semi-arid environments. Vadose Zone Journal, https://www.soils.org/publications/vzj/articles/12/4/vzj2013.03.0052?highlight=&search-result=1)Arnold, S., Y. Kailichova, and T. Baumgartl. 2014. Germination of Acacia harpophylla (Brigalow) seeds in relation to soil water potential: implications for rehabilitation of a threatened ecosystem. PeerJ, https://peerj.com/articles/268/
Dichanthium grasslands are another typical habitat of the area while pockets of thicker woodland of brigalow mixed with Casuarina cristata and ooline occur in moister valleys and vine thickets, wetlands, and softwood scrubs are sometimes found although in their undeveloped state, these specialised micro-habitats are rare today. There is a particularly rich variety of habitats in areas such as Isla Gorge and Blackdown Tableland in the sandstone belt of the Carnarvon Range. The Northern Brigalow Belt is one of fifteen national biodiversity hotspots in Australia.
Fauna The region is home to the unadorned rock-wallaby and the black-striped wallaby, which lives in the areas of vine thicket along with a wingless dung beetle (Onthophagus apterus). Two endangered mammals are found in the Brigalow Belt; the bridled nail-tail wallaby in Taunton and Idalia National Parks, and the burrowing northern hairy-nosed wombat in the grassland and eucalyptus of Epping Forest National Park. There are also populations of dunnart, wallaby, bat and koala. Birds found here include black-throated finch and russet-tailed thrush, while endemic reptiles include the Fitzroy River turtle.Ponce Reyes, Rocio; Firn, Jennifer; Nicol, Sam; Chades, Iadine; Martin, Tara; Stratford, Danial; Whitten, Stuart; Carwardine, Josie. Priority threat management for imperilled species of the Queensland Brigalow Belt. CSIRO: CSIRO; 2016. https://doi.org/10.4225/08/58542c54413ee
A variety of spiders and insects are found there, including Euoplos dignitas, an armoured trapdoor spider discovered in 2023.
Already extinct fauna include the white-footed rabbit-rat and the Darling Downs hopping mouse.Ponce Reyes, Rocio; Firn, Jennifer; Nicol, Sam; Chades, Iadine; Martin, Tara; Stratford, Danial; Whitten, Stuart; Carwardine, Josie. Priority threat management for imperilled species of the Queensland Brigalow Belt. CSIRO: CSIRO; 2016. https://doi.org/10.4225/08/58542c54413ee
Threats and preservation Together with the Mulga Lands, the Brigalow Belt are where most of Queensland's land clearing is occurring. Much of the brigalow woodland has been cleared or radically reduced to the extent that some wildlife, failing to thrive in the altered environment, has become extinct here with a number of the remaining communities threatened or endangered. The clearance of brigalow and poplar box is ongoing as there are a number of nature reserves of which do protect the various types of habitat found in the Belt including brigalow and eucalyptus woodland, grassland, vine thicket, high peaks, sandstone gorges and wetlands however these tend to be located on the sandstone uplands rather than the fertile lowlands, where the brigalow woodlands are still vulnerable to clearance and are often limited to small areas of parkland. The grasslands of the region are also under threat from introduced pasture grasses such as buffelgrass and weeds such as Congress weed. One particular threat comes from alterations to natural flow patterns caused by the addition of dams and weirs which impact the riverine and floodplain plant and animal species.Ponce Reyes, Rocio; Firn, Jennifer; Nicol, Sam; Chades, Iadine; Martin, Tara; Stratford, Danial; Whitten, Stuart; Carwardine, Josie. Priority threat management for imperilled species of the Queensland Brigalow Belt. CSIRO: CSIRO; 2016. https://doi.org/10.4225/08/58542c54413ee
Protected areas A little more than two per cent of the Brigalow Belt lies within national parks and other protected areas. The largest national parks in the Brigalow Belt are: Taunton (the largest at 115 km2); Epping Forest, Dipperu, Bowling Green Bay, Goodedulla National Park, Chesterton Range National Park, Homevale National Park, Blackdown Tableland National Park, Expedition National Park, and Carnarvon National Park.
Subregions IBRA subregions of the Brigalow Belt North include Townsville Plains, Bogie River Hills, Cape River Hills, Beucazon Hills, Wyarra Hills, Northern Bowen Basin, Belyando Downs, Upper Belyando Floodout, Anakie Inlier, Basalt Downs, Isaac–Comet Downs, Nebo–Connors Ranges, South Drummond Basin and Marlborough Plains. IBRA regions and subregions: IBRA7IBRA region / subregionIBRA codeAreaStates Location in AustraliaBrigalow Belt North BBN Qld Townsville Plains BBN01 Bogie River Hills BBN02 Cape River Hills BBN03 Beucazon Hills BBN04 Wyarra Hills BBN05 Northern Bowen Basin BBN06 Belyando Downs BBN07 Upper Belyando Floodout BBN08 Anakie Inlier BBN09 Basalt Downs BBN10 Isaac-Comet Downs BBN11 Nebo-Connors Ranges BBN12 South Drummond Basin BBN13 Marlborough Plains BBN14
IBRA regions and subregions: IBRA7IBRA region / subregionIBRA codeAreaStates Location in AustraliaBrigalow Belt South BBS Qld / NSW Claude River Downs BBS01 Woorabinda BBS02 Boomer Range BBS03 Mount Morgan Ranges BBS04 Callide Creek Downs BBS05 Arcadia BBS06 Dawson River Downs BBS07 Banana-Auburn Ranges BBS08 Buckland Basalts BBS09 Carnarvon Ranges BBS10 Taroom Downs BBS11 Southern Downs BBS12 Barakula BBS13 Dulacca Downs BBS14 Weribone High BBS15 Tara Downs BBS16 Eastern Darling Downs BBS17 Inglewood Sandstones BBS18 Moonie-Commoron Floodout BBS19 Moonie-Barwon Interfluve BBS20 Northern Basalts BBS21 Northern Outwash BBS22 Pilliga Outwash BBS23 Pilliga BBS24 Liverpool Plains BBS25 Liverpool Range BBS26 Talbragar Valley BBS27 Narrandool BBS28
References
Sattler, P. S. and R. D. Williams (1999) (eds) The Conservation Status of Queensland’s Bioregional ecosystems. Environmental Protection Agency, Brisbane IBRA Version 6.1 data. (Search in "Title" for "IBRA").
External links