Australian Natural Resources Atlas

Natural Resource Topics

Rangelands - Overview

Location map of Brigalow Belt South bioregion

photograph

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ATSIC Boundaries

Introduction

The Brigalow Belt South bioregion covers an area of 269,300 sq km. Most of this bioregion (81%) is within Queensland and approximately 19% is in NSW. Not all of the region is rangelands as much has been developed for cropping and improved pasture which is generally found on the more fertile soils that originally carried brigalow (Acacia harpophylla), or grasslands of eastern mid-height grasses (Dichanthium and Bothriochloa spp.). The NSW portion of the bioregion is not considered rangelands. The rangelands occur as eucalypt woodland, often as a mosaic pattern with improved pasture and cropping lands.

The main town centres within the rangelands are Roma and St George. The bioregion has a hot to warm sub humid climate.

Natural Environment

Climate

The average rainfall for the rangelands is between 500 mm and 750 mm and is variable. Rainfall can occur throughout the year but there tends to be a higher proportion of summer rainfall in the northern rangelands areas, which are influenced by summer tropical lows. There is a slight winter rainfall peak in the southern areas, which declines towards the north.

The mean summer temperature at Roma ranges from approximately 20.4° C to 34.4° C. The mean winter temperatures range from 4° C to 19° C.

Climate averages are available for Roma, Queensland: www.bom.gov.au/climate/map/climate_avgs/a35.shtml.

For monthly rainfall and temperature graphs refer to Bureau of Meteorology website: www.bom.gov.au/climate/forms/map_forms/new_imagemaps/qld_name.html.

Current seasonal conditions and their historical context can be provided by satellite imagery. The Normalised Difference Vegetation Index (NDVI) is a measure of the vegetation ‘greenness’. The NDVI for the Brigalow Belt South bioregion for this year and previous years can be found at: http://www.environment.gov.au/erin/ndvi/ttrace/bbs.html.

For additional climate information the Queensland Department of Natural Resources ‘The Long Paddock’ at: www.dnr.qld.gov.au/longpdk provides seasonal variability information and the latest El Ni?o Southern Oscillation (ENSO) information. ‘Silo’ at: www.dnr.qld.gov.au/resourcenet/climate/#silo provides agro meteorological data, such as rainfall, temperature, radiation, climate outlook products. The Queensland Department of Natural Resources’ Patched Point Dataset and Data drill at: www.dnr.qld.gov.au/resourcenet/silo/index.html, provides information on climatic risk management in agriculture, pastoralism, water resources and natural resource management.

Landforms and hydrology

A number of provinces have been defined within the Brigalow Belt South bioregion on the basis of vegetation, climate and geology. Five of these provinces are within the rangelands portion of the bioregion. For more information refer to Sattler & Williams (1999).

The rangelands portion of this bioregion lies in the upper catchment of the Murray-Darling Basin. It includes the headwaters of the Warrego River and the Maranoa River, which form part of the Darling River system.

The geology of the Brigalow Belt bioregion is complex. The rangelands portion of the bioregion is predominantly Jurassic to Cretaceous (65-205 millions years ago) sediments of the Great Artesian Basin and Tertiary (less than 65 million years ago) basalts. The northern area of the rangelands includes part of the Galilee Basin, which consists of Triassic (251-205 million years old) sediments. The rangelands comprise undulating to hilly landscape with areas of low ridges and deep valleys as well as flat alluvial plains in the south.

For more detailed geological information and map refer to the Australian Geological Survey Organisation website: www.agso.gov.au/map/ and the Department of Mines and Energy, Queensland: www.dme.qld.gov.au/gsd/index.htm.

Soils

The Brigalow country is generally known for its clay soils that are relatively fertile and regarded as productive agricultural areas. The soils are generally earths, cracking clays and areas of deep sands. For further information on soils refer to Galloway et al (1974), Isbell (1962), Storey et al (1967) and Sattler & Williams (1999) and the Murray-Darling Basin Soil Information at: www.brs.gov.au/mdbsis.

Vegetation

The rangelands part of the bioregion includes mixed eucalypt woodland with a variable density shrubby understorey. The dominant woodland vegetation includes narrow-leaved ironbark (Eucalyptus crebra), spotted gum (Corymbia citriodora), cypress pine (Callitris glaucophylla) and bloodwoods (Corymbia spp.). The western rangelands portion is predominantly brigalow (Acacia harpophylla), belah (Casuarina cristata) and poplar box (Eucalyptus populnea)open-forest and woodland Isbell (1962), Johnson (1964) and Nelder (1984).

For a list of rare and threatened flora and vegetation descriptions of the bioregion refer to Sattler & Williams (1999).

Fauna

The fauna of this region requires further systematic survey. There is an incomplete knowledge of the habitat, distribution and abundance of birds, mammals, reptiles, and amphibians, and particular groups such as invertebrates and fish are particularly lacking in information.

Three mammal and one bird species that occurred in the bioregion are now presumed extinct; they are the white-footed rabbit-rat (Conilurus albipes), western quoll (Dasyurus geoffroii geoffroii), downs hopping-mouse (Notomys mordax) and the paradise parrot (Psephotus pulcherrimus). Ten species of birds, mammals and reptiles are now regarded as endangered with a further 30 species classified as being vulnerable. Thirty-five species of vertebrates are regarded as being rare. As many as 144 plant species are regarded as threatened because of extensive cultivation and tree clearing and the impact of livestock grazing. For a list of rare and threatened fauna and fauna surveys of the Brigalow Belt refer to Sattler & Williams (1999).

Land Tenure & Use

Land tenure

The Brigalow Belt South has a mix of tenures, ranging from private freehold to crown lease. Generally the rangelands areas are leasehold land. The Carnarvon National Park is a major conservation reserve within the rangelands portion of the bioregion (Sattler & Williams 1999).

Land use

Most of this bioregion is utilised for agriculture. The rangelands portion is mainly used for beef cattle grazing. Cattle breeding and fattening steers for the export market are major enterprises. Some of the steers are purchased at northern sales such as Charters Towers and transported by road train to fattening properties in the bioregion. Extensive dryland cropping also occurs.

There is intensive agriculture close to the border with the rangelands. For example, there is irrigated cotton, sunflower and soybean production around the St. George and Dalby areas.

Condition Of the Landscape

Land degradation

Some brigalow soils are prone to water erosion. Soils that are exposed through overgrazing or tree clearing may be vulnerable to high intensity summer thunderstorms.

The salinity levels in the rivers that flow from the bioregion are of concern. There is also potential for salinity to be a major problem if the watertable rises in areas that have been cleared, although the extent of this is a topic of intense conjecture at present.

Soil structure decline is a problem for some duplex soils that were once covered in open forest and woodland but are now managed as grasslands or for cultivation.

The main issue in the bioregion is the rate of land clearing and the difficulty in setting aside conservation reserves that contain examples of the brigalow ecosystems. The brigalow country has been systematically cleared since the 1970’s. For example, 61% of the natural vegetation still existed in the St. George area in 1974 but by 1994 only 28 % remained (Bailey, 1984).

The State-wide Landcover And Tree Study (SLATS) undertaken by the Queensland Department of Natural Resources, provides vegetation cover and cover change information using Landsat Thematic Mapper ™ satellite imagery. SLATS provides baseline land cover mapping over the entire State of Queensland (www.dnr.qld.gov.au/resourcenet/veg/slats/index.html).

Pest species

The brigalow region was one of those worst affected by prickly pear (Opuntia stricta). However its control was achieved between 1925-32 with the larvae of the cactoblatis moth (Cactoblastis cactorum). This was one of the best examples of effective biological control of a weed anywhere in the world (Mann 1970).

Mother-of millions (Bryophyllum delagoense), saffron thistle (Carthamus lanatus) and native rice flower (Pimelea trichostachya) are significant pests in rangelands

Feral animals such as the foxes and cats are predators of wildlife. Feral horses occur in some of the rugged parts of the Central Highland, which are part of this bioregion.

Social & Economic Aspects

People

The main centres in the rangelands area are Roma and St. George. Roma is 500 km west of Brisbane on the Warrego Highway and has a population of approximately 6,000. It is the town where Captain Starlight was put on trial for cattle stealing, which is the subject of the Australian classic ‘Robbery Under Arms’. Australia’s first gas discovery was at Roma in 1900 and it now supplies Brisbane through a 450 km pipeline.

There has always been a vibrant pastoral economy — initially with sheep and now with cattle. Since the 1970’s dryland agriculture has increased dramatically in importance to the local economy

St. George has a population of approximately 2,300 people and is 524 kms west of Brisbane on the Carnarvon Highway. It was named by Thomas Mitchell after he crossed the Balonne River on St. George’s Day in 1846.

There is ample evidence that this part of the bioregion supported a large Aboriginal population from the archaeological record derived from excavations, and the extensive paintings and rock art in places such as Carnarvon Gorge and other rocky ranges. There were large areas of grasslands interspersed with the brigalow and rich riverine and creek environments that supported hunting and gathering. The region was marked by a fierce defence by Aboriginal people against the first European invaders. Many white pastoralists lost their lives and there were massive reprisals that took many Aboriginal lives.

The bioregion is within the ATSIC regions of Roma and Tamworth and are managed by their respective regional councils, Goolburri and Kamilaroi (McLennan, 1997). For more information on the Aboriginal people of this region refer to Horton, (1994) and the relevant websites in the reference list.

Resources, References & Contacts

Publications

Websites and contacts

Aboriginal languages of Australia: http://www.dnathan.com/VL/

Aboriginal Studies WWW Virtual Library:

http://www.ciolek.com/WWWVL-Aboriginal.html

Australian Landcare Council:

www.dpie.gov.au/agfor/landcare/org/alc.html.au

Aboriginal Torres Strait Islanders Commission (ATSIC):

www.atsic.gov.au/

Australian Geological Survey Organisation, Geology of Australia:

Bureau of Meteorology, Climate averages:

www.bom.gov.au/climate/map/climate_avgs/a17.shtml

http://www.bom.gov.au/climate/map/climate_avgs/a37.shtml

Bureau of Meteorology, Temperature and rainfall graphs: www.bom.gov.au/climate/forms/map_forms/new_imagemaps/qld_name.html

Bureau of Rural Sciences, Digital Atlas of Australian Soils:

www.affa.gov.au/content/output.cfm?ObjectID=D2C48F86-BA1A-11A1-A2200060B0A05758

Department of Mines and Energy, Queensland:

www.dme.qld.gov.au/gsd/index.htm

Department of Environment and Heritage, Normalized Difference Vegetation Index (NDVI) information including bioregional information:

www.environment.gov.au/erin/ndvi/index.html

Murray-Darling Basin Soil Information:

www.brs.gov.au/mdbsis/

National Property Management Planning Campaign, The Future profit program:

www.dpi.qld.gov.au/ruraldev/futureprofit/Welcome.html

Queensland Department of Natural Resources. ‘Long Paddock’:

www.dnr.qld.gov.au/longpdk

Queensland Department of Natural Resources. ‘Silo’:

www.dnr.qld.gov.au/resourcenet/climate/#silo

Queensland Department of Natural Resources. Patched Point Dataset and Data drill:

www.dnr.qld.gov.au/resourcenet/silo/index.html,

Queensland’s Environmental Protection Agency. National Park information, animal and plant species information including rare and threatened species:

www.env.qld.gov.au

Queenslands Parks and Wildlife Service:

www.env.qld.gov.au/environment/park/discover/

Rural Lifestyles Queensland:

www.rlq.dcilgp.qld.gov.au

State-wide Land cover and Tree Study (SLATS) Vegetation cover and cover change information using Landsat Thematic Mapper ™ satellite imagery:

www.dnr.qld.gov.au/resourcenet/veg/slats/index.html

Link to the Map Maker to make a map using this information.

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