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In this section you will find detailed information, including national overviews and state and regional level assessments, from the 2000-2002 National Land and Water Resources Audit theme assessments.
Rangelands - Overview
Gulf Falls and Uplands
Summary
- Located inland from the Gulf of Carpentaria.
- Centres include Borroloola, and Ngukurr, which is on the southern edge of Arnhem Land.
- The McArthur lead and zinc mine is within the region.
- Contains spectacular gorges, water holes and dissected sandstone plateaux for example China Walls.
- Eucalyptus woodlands over hummock or tussock grasses are the dominant vegetation type, although monsoon forests and vine thickets occur along rivers in the sandstone country.
- Around two thirds of the bioregion is pastoral leasehold, and nearly one third is Aboriginal land.
ATSIC Boundaries
Catchment Basins
Statistical Local Areas
Introduction
Gulf Falls and Uplands bioregion consists of 118,500 sq kms of land that lies inland from the Gulf of Carpentaria. About 95% of the bioregion is within the Northern Territory, but it extends slightly into Queensland.
The bioregion is relatively rugged consisting mainly of pastoral leases, although there are considerable areas of Aboriginal land
There are few settlements in the bioregion. Ngukurr, an Aboriginal settlement of about 900 people on the Roper River on the southern edge of Arnhem Land is one of larger centres of population. Borroloola (551) also lies just within the bioregion. The McArthur River mine is within the bioregion.
Natural Environment
Climate
The bioregion falls within the monsoonal northern Australia, although there is a wide range of conditions within this region. Rainfall decreases from about 1,000 mm in the north to 400mm in the southeast. Although summer rainfall is dominant throughout the region, rainfall in the northwest is more strongly concentrated in the January — March period than in the southeast.
North of Roper Bar temperatures range from 13.6° C -30.1° C (Jun/Jul) in winter to 25° C-39° C in summer (Nov/Dec). Temperatures are slightly lower, and temperature ranges slightly higher towards the south east of the region.
Climate averages are available for Borroloola,
http://www.bom.gov.au/climate/map/climate_avgs/a14ga.shtml
Temperature and rainfall graphs are available for Borroloola,
www.bom.gov.au/climate/forms/map_forms/new_imagemaps/nt_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 Gulf Fall Uplands bioregion for this year and previous years can be found at, www.environment.gov.au/erin/ndvi/ttrace/gfu.html
Landforms and hydrology
There are two major underlying geological units in the bioregion. Towards the coast is the McArthur Basin consisting of Proterozoic (545-2500 million years ago) marine and continental sediments and volcanics (1,000 — 2,500 million years old). Further inland is the Georgina Basin consisting of Late Proterozoic — Devonian (1,000 — 4,000 million years ago) marine sediments and volcanics.
For more detailed geological information and map refer to the Australian Geological Survey Organisation website: www.agso.gov.au/map/ and the Northern Territory Geological Survey website:
www.dme.nt.gov.au/ntgs/ntgs/geo_overview/geo_over.html
The Gulf Falls and Uplands bioregion is known for its spectacular gorges and waterholes, which are found along the Limmen Bight, Robinson, Calvert and Nicholson Rivers. Dissected sandstone plateaux have created dramatic formations, with deeply cut valleys often containing rainforest remnants. The highest of the steep sided gorges is the China Wall, which raises some 200 metres above the Nicholson River. (Kerle, 1996)
Soils
There are two major underlying geological units in the bioregion. Towards the coast is the McArthur Basin consisting of Proterozoic (545-2500 million years ago) marine and continental sediments and volcanics (1,000 — 2,500 million years old). Further inland is the Georgina Basin consisting of Late Proterozoic — Devonian (1,000 — 4,000 million years ago) marine sediments and volcanics.
For more detailed geological information and map refer to the Australian Geological Survey Organisation website: www.agso.gov.au/map/ and the Northern Territory Geological Survey website:
www.dme.nt.gov.au/ntgs/ntgs/geo_overview/geo_over.html
The Gulf Falls and Uplands bioregion is known for its spectacular gorges and waterholes, which are found along the Limmen Bight, Robinson, Calvert and Nicholson Rivers. Dissected sandstone plateaux have created dramatic formations, with deeply cut valleys often containing rainforest remnants. The highest of the steep sided gorges is the China Wall, which raises some 200 metres above the Nicholson River. (Kerle, 1996)
Vegetation
1,342 species have been identified in the bioregion, including 46 that are rare and threatened (Connors et. al., 1996). For a complete list of rare and threatened species refer to: www.nt.gov.au/paw/fauna/bau/intro.htm
The dominant vegetation communities are eucalypt woodlands with hummock grass or tussock grass understorey (Connors et. al., 1996). However, the varied topography, particularly in the northwest is reflected in the diversity of plant communities. The most widespread communities are:
In the southeast a low open woodland of snappy gum (Eucalyptus leucophloia) with bloodwood (Corymbia terminalis), ironwood (Erythrophleum chlorostachys) over curley spinifex (Plectachne pungens) hummock grassland. Other associations include northern box (E. tectifica) with white grass (Sehima nervosum) and golden beard grass (Chrysopogon fallax).
Variable barked bloodwood (Corymbia dichromophloia) and stringybark (E. tetrodonta) also form low open woodland with Darwin woolly butt (E. miniata). In some areas woodlands include rusty bloodwood (Corymbia ferruginea), lancewood (Acacia shirleyi). Coolibah (E. microtheca) occurs along some creeks and there are extensive paperbark swamps (Melaleuca citrolens) (Kerle, 1996).
In the north west of the region woodland communities include stringy bark, cypress pine (Callitris intratropica) and silver box (E. pruinosa) (Connors et. al., 1996). Northern cypress-pine has suffered where traditional Aboriginal fire regimes have been changed (Woinarski, et. al., in prep.).
Vine thickets are scattered along the rivers through the sandstone country and contain relict species including, rushes and reeds and the fern (Lygodium microphyllum) as well as undescribed species of ferns (Morton et. al., 1995).
Fauna
435 species of vertebrates, including 24 species that are rare and threatened have been identified in the bioregion (Connors et. al., 1996). Refer to the web site for further details: www.nt.gov.au/paw/fauna/bau/intro.htm
Several bird and mammal species appear to have become extinct or rare in this bioregion over the last century. Bird species include partridge pigeon (Geophaps smithii), mammal species include golden-backed tree-rat (Mesembriomys macrurus), golden bandicoot (Isoodon auratus), northern brown bandicoot (Isoodon macrorus), northern quoll (Dasyurus hallucatus) and the brush-tail possum (Trichosurus vulpecula) (Woinarski, et. al., in prep.).
Rare and threatened species identified by Connors, et. al., (1996) include the red goshawk (Erythrotriorchis radiatus), square-tailed kite (Lophoictinia isura), grey falcon (Falco hypoleucos), crested shrike-tit (Falcunculus frontatus), carpentarian grasswren (Amytornis dorotheae), painted honeyeater (Grantiella picta), gouldian finch (Erythrura gouldiae), ghost bat (Macroderma gigas), central pebble mound mouse (Pseudomys johnsoni) and thecarpentarian rock-rat (Zyzomys palatalis).
The freshwater crocodile (Crocodylus johnstoni) occur in some creeks.
Land Tenure & Use
Land tenure
Most of this bioregion is pastoral leasehold land. There are also extensive areas of Aboriginal freehold land. 66.3% of the NT portion of the bioregion (or 69,530 sq kms) is pastoral leasehold, 26% (27,302 sq kms) is Aboriginal freehold, and 6.7% is reserved area (7,067 sq kms).
Areas reserved for conservation include Elsey National Park in the Northern Territory, and part of the Lawn Hill National Park on the Queensland side of the border. A large National Park is being established at Limmen Gate in the Northern Territory as at 2000 (Woinarski, et. al., in prep.).
Land use
Cattle grazing is the dominant use within the region. This is characterized in the region by a low input of labour and capital and few fences. The industry is generally of marginal profitability or non viable in the region (Woinarski, et. al., in prep.). Also refer to the Tropical Savanna website: www.savanna.ntu.edu.au/information/savannaexplorer.html
On Aboriginal land in the Northern Territory some traditional mosaic burning regimes are being maintained (Tropical savanna site fire)
There is one large lead and zinc mining enterprise at McArthur River, and there are several smaller operations in the bioregion.
Tourism is a growing industry in the region, based primarily around the spectacular sandstone escarpment. Mataranka Pool Nature Park, in the north west of the bioregion attracts more than 150,000 visitors annually.
Condition Of the Landscape
Land degradation
Degradation of some areas by overstocking of cattle has been documented (Woinarski, et. al., in prep.). Morton, et. al., (1995) also notes that the rocky ranges of this bioregion are a significant biological refuge but these require better cattle management, as well as improved fire management.
Monsoon rainforests in the region are being degraded by inappropriate fire regimes weeds and feral animals. Inappropriate fire regimes are also now reducing the floristic diversity of heathland vegetation in sandstone plateau and escarpment areas. This is impacting on the abundance and distribution of fauna associated with these areas, including the carpentarian grass-wren (Amytornis dorotheae) (Woinarski, et. al., in prep.).
There are localised impacts of tourism on some sites (Connors et. al., 1996). There are also impacts of mining.
Pest species
Pest animals include cane toads, horses, pigs and cats. (For more details refer to Connors et. al., 1996, www.savanna.ntu.edu.au/information/savannaexplorer.html)
Connors et. al., 1996 identify 25 weed species in the bioregion, these include bellyache bush (Jatropha gossypifolia), spinyhead sida (Sida acuta), noogoora burr (Xanthium pungens), parkinsonia (Parkinsonia aculeata), mesquite (Prosopis spp), khaki weed (Alternanthera pungens) and hyptis (Hyptis suaveolens). Mexican poppy (Argemore ochroleuca) occurs in some catchments including the McArthur River.
Rubber vine (Cryptostega grandiflora) is a potential threat to this bioregion, it is already a major problem on the Queensland side of the border.
Social & Economic Aspects
People
The pastoral industry in this region is very extensive, and supports a sparse population.
There is a significant Aboriginal population in the region. Aboriginal lands include Wannyi / Garawa on the Northern Territory side of the Queensland border, Alawa, Hodgson Downs, Yutpundji Djindiwirritj, and parts of Garawa, Narwinbi, Beswick and Arnhem Land. The bioregion is within the Katherine ATSIC region. For more information on the Aboriginal people of this region refer to Horton, (1994) and the relevant websites in the reference list.
As well as the Northern Territory Government, the Northern Lands Council (NLC) provides support and services to Aboriginal communities in this region, refer to the NLC web site: http://www.ozemail.com.au/nlc95/
One of the major areas of economic activity in the bioregion is the MacArthur River lead and zinc mine, including the associated infrastructure and workforce in the area around Cape Crawford and Borroloola.
Tourism is a growing industry in the region, based on the area’s spectacular scenery. The region is also popular for fishing in the rivers that flow into the Gulf of Carpentaria.
Resources, References & Contacts
Publications
- Connors G., Oliver B., & Woinarski, J. 1996, Bioregions in the Northern Territory: Conservation Values, Reservations Status and Information Gaps. Final report to ANCA National Reserves System Cooperative Program (Project N607), Parks and Wildlife Commission of the Northern Territory, Palmerston, Northern Territory.
- Finlayson, M., Yibaruk, D., Thurtell, L., Storrs, M. and Cooke, P. 1999, Local Community Management of the Blyth / Liverpool wetlands, Arnhem Land Northern Territory Supervising Scientist Report 137, Supervising Scientist Group, Environment Australia, Jabiru, Northern Territory
- Hema Maps 1997, Australia Touring Atlas, Fergies Colour Printers, Brisbane, Queensland.
- Horton, D. R. 1994, The Encyclopaedia of Aboriginal Australia, Aboriginal Studies Press for the Australian Institute of Aboriginal and Torres Strait Islander Studies, Canberra, ACT.
- Kerle, J.A. 1996, Bioregions of the Northern Territory. Draft report Conservation Commission of Northern Territory, Palmerston, Northern Territory.
- McLennan. W. 1997, 1994 National Aboriginal and Torres Strait Islander Survey: Social Atlas, Australian Bureau of Statistics, Canberra, ACT.
- Storrs, M.J. & Finlayson, C.M. 1997, Overview of the conservation status of wetlands of the Northern Territory. Supervising Scientist Report 116, Supervising Scientist, Barton ACT.
- Thackway, R. & Cresswell I.D. 1995, An Interim Biogeographical Regionalisation for Australia: a Framework for Setting Priorities in the National Reserves System Cooperative Program, Australian Nature Conservation Agency, Canberra.
- Woinarski J., Fensham, R., Whitehead, P. & Fisher, A., with map production by Verhagen, C. in prep., Biodiversity in the Australian Rangelands: a Review of Changes in Status and Threatening Processes. Draft report prepared as a resource document for Project 3: Developing an Adaptive Framework for Monitoring Biodiversity in Australia's Rangelands, of the National Land and Water Resources Audit, Theme 4 (Rangelands monitoring) by the Tropical Savannas Cooperative Research Centre, Darwin, Northern Territory.
Websites and contacts
Aboriginal languages of Australia
Aboriginal Studies WWW Virtual Library
http://www.ciolek.com/WWWVL-Aboriginal.html
Australian Geological Survey Organisation, Geology of Australia
www.agso.gov.au/map/
Bureau of Meteorology, Climate averages
http://www.bom.gov.au/climate/map/climate_avgs/a14ga.shtml
http://www.bom.gov.au/climate/map/climate_avgs/a14f.shtml
Bureau of Meteorology, Temperature and Rainfall graphs
www.bom.gov.au/climate/forms/map_forms/new_imagemaps/nt_name.html
Charles Sturt University: Guide to Australia - NT
http://www.csu.edu.au/australia/nt.html
Department of Primary Industries, Fisheries and mines of the Northern Territory
www.nt.gov.au/dpifm
Environment Australia, Normalized Difference Vegetation Index information including bioregional information
www.environment.gov.au/erin/ndvi/index.html
Northern Land Council
www.nlc.org.au
Northern Territory Department of Natural Resources, Environment and the Arts
www.nt.gov.au/nreta
Northern Territory Tourist Commission
nttc.com.au/
Tropical Savanna Co-operative Research Centre
www.savanna.ntu.edu.au/information/savannaexplorer.html
Link to the Map Maker to make a map using this information.
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