Rangelands - Overview
Daly Basin
Summary
- Tropical monsoonal climate
- The Daly River passes through the bioregion, including its tributaries such as the Katherine River.
- Katherine is the major centre within the bioregion with a population of 10,000.
- Pastoralism has traditionally been the dominant land use.
- There is a growing horticultural industry in the region including peanuts, melons and mangoes.
- Tourism is important in the region, with a number of spectacular national parks
ATSIC Boundaries
Catchment Basins
Statistical Local Areas
Introduction
The Daly Basin covers 20,900 sq kms in the top end of the Northern Territory.
The bioregion contains gently undulating plains and scattered lowland remnants. It is crossed by the Daly River and its tributaries including the Katherine River.
The bioregion includes the city of Katherine. Extensive areas are devoted to horticulture, including the rich soils around Tipperary Station and the Douglas River (Kerle, 1996).
Natural Environment
Climate
The Daly Basin has a tropical monsoonal climate with distinct wet and dry seasons and high temperatures throughout the year. Almost all rain falls in the wet season from November to March.
Rainfall decreases from 1400mm in the north of the region to 950mm in the south. Katherine, in the south of the bioregion has a mean annual rainfall of 972mm.
Temperature ranges increase towards the south of the bioregion. Katherine has a summer range between 24? C - 38? C and a winter range from 13? C-29? C (Kerle, 1996).
Climate averages are available for Katherine:
http://www.bom.gov.au/climate/map/climate_avgs/a14ga.shtml
Temperature and rainfall graphs are available for Katherine:
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 Daly Basin bioregion for this year and previous years can be found at: http://www.environment.gov.au/erin/ndvi/ttrace/dab.html
Landforms and hydrology
The Daly River Basin is one of the more homogenous bioregions in the NT. It contains gently undulating plains with scattered low plateau remnants with some rocky hills and gorges along its western edge. The bioregion incorporates the Daly River Basin formations, which are predominantly Cambrian (500 million years ago) limestones with some sandstones and interbedded shales. There are also some areas of conglomerates, sandstones, siltstones and claystones resulting from deposition during the Cretaceous (100 million years ago). During the Tertiary period (40 million years ago) there was some uplift and associated warping and faulting.
The region is crossed by the Daly River and its tributaries, which include the King, Katherine, Flora, Edith and Douglas Rivers (Kerle, 1996).
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:
http://www.dme.nt.gov.au/ntgs/ntgs/geo_overview/geo_over.htm
Soils
Soils vary from sandy and loamy red and yellow earths to lateritic and yellow podsolic soils on the gently undulating land, often over compact clay sub-soils. Heavier textured grey soils are found on the floodplains and levees of the Daly River system while stony and skeletal soils occur amongst the hills (Kerle, 1996).
For more soils information refer to the Digital Atlas of Australian Soils
Vegetation
1,077 plant species have been recorded in the bioregion including 40 rare and threatened species (Connors et. al., 1996). Lists of these rare and threatened species can be found at: www.nt.gov.au/paw/fauna/bau/intro.htm
The bioregion is dominated by Eucalypt woodlands with tussock grass understorey. There are also small areas of monsoon forest and billabong fringing vegetation (Kerle, 1996).
The woodland communities vary according to topography.
On the undulating plateaux and plains are open forests with mixed stands of Darwin woolly butt (Eucalyptus miniata) and stringybark (E. tetrodonta), with a shrub layer and ground layer dominated by sorghum species. Other species include fan palm (Livistonia humilis) and zamia palm (Cycas armstrongii). Other associations on the undulating country include northern box (E. tectifica), round-leaved bloodwood (E. latifolia) and ironwood (Erythrophleum chlorostachys) with fan palms and tall grasses such as sorghum and giant spear grass (Heteropogon triticeus).
On the rocky ridges and outcrops woodlands include stringybark, Darwin woolly butt and variable-barked bloodwood (C. dichromophloia) over curley spinifex (Plectrachne pungens) and golden beard grass (Chrysopogon fallax).
Along watercourses, billabongs and in poorly drained soils are communities of paperbark (Melaleuca viridiflora), screw palm (Pandanus spiralis), river pandanus (P. aquaticus) and freshwater mangrove (Barringtonia acutangula) (Kerle, 1996).
Fauna
417 vertebrate species have been recorded in the bioregion, including 18 species that are rare and threatened (Connors et. al., 1996). Lists of these rare and threatened species can be found at: www.nt.gov.au/paw/fauna/bau/intro.htm
Several larger rodents and small to medium dasyurids have declined over the last century, although the extent and timing is difficult to define. The current and projected levels of clearing suggest there will be an overall change in species composition of this bioregion (Woinarski, et. al., in prep.).
There is a high diversity of birds including migratory and water birds. Monsoon specialists include the rainbow pitta (Pitta iris), rose-crowned fruit dove (Ptilinopus regina) and torresian imperial pigeon (Ducula bicolar). Amongst the billabong fringing vegetation are found honeyeaters, flycatchers and finches. The endangered gouldian finch (Erythrura gouldiae) is known from several locations in this bioregion.
The pig nosed turtle (Carettochelys insculpta) also occurs in the region (Kerle, 1996)
Land Tenure & Use
Land tenure
60.6% of bioregion is pastoral lease or freehold (12,573 sq kms). Aboriginal freehold consists of 12.3% of the bioregion (2,541 sq kms), and the area reserved for conservation is 1.7% (358 sq kms)
Most of the area reserved for conservation is in the extreme north (the southern part of Litchfield National Park). Other reserves include Umbrawarra Gorge Nature Park, Cutta Cutta Caves Nature Park and Douglas Hot Springs Nature Park (Connors et. al., 1996).
Aboriginal lands include Jawoyn, Barnjarn and part of Wagiman.
Land use
Pastoral leases, many of which were established in the 1880's, cover most of the Daly Basin. More recently land use in parts of the region has been changing from extensive grazing to manage grazing and intensive agriculture. This region is an extremely important part of the rapidly growing horticultural industry of the NT (Kerle, 1996).
Horticultural production includes grain sorghum, peanuts, melons and mangoes. There are proposals to increase the extent of large-scale intensive horticulture (Woinarski, et al., in prep.). This is a small bioregion that has been extensively modified, and likely to be subject to a marked increase in intensive agricultural use, including the subdivision of existing pastoral properties into smaller land parcels (Connors, et. al., 1996). There are several large mines in the region.
Tourism is an important activity in the region focussed mainly on Litchfield National Park, the Katherine area and the Daly River (Woinarski, et. al., in prep.).
Condition Of the Landscape
Land degradation
Changed fire regimes, principally from frequent localised 'cool' burns to more extensive late dry season fires are affecting several vegetation types in this bioregion, particularly rainforests and sandstone environments (Woinarski, et. al., in prep.).
The northern cyprus pine (Callitris intratropica) which is a dominant or sub-dominant tree across much of this bioregion, has and continues to suffer dramatic decline in many areas where traditional Aboriginal fire regimes have been changed (Woinarski, et. al., in prep.).
In comparison with other rangelands areas a relatively high proportion (around 8%) of this bioregion has been cleared, and this is likely to increase substantially in the near future (Woinarski, et. al., in prep.).
Pest species
30 weed species have been identified in the bioregion (Connors, et. al., 1996). For a complete list: www.nt.gov.au/paw/fauna/bau/intro.htm. For more information on weeds in the Darwin-Kakadu region refer to the Tropical Savanna website: www.savanna.ntu.edu.au/information/savannaexplorer.html
Some weed species include rubber bush (Calotropis procera), hyptis (Hyptis suaveolens), devil's claw (Martynia annua), parkinsonia (Parkinsonia aculeata), spiny head sida (Sida acuta), and noogoora burr (Xanthium strumarium).
Feral animals are widespread including pigs, cattle, donkeys, horses, cats, and water buffalo. (Woinarski, et. al., in prep.)
Social & Economic Aspects
People
Katherine has a population of around 10,000 is situated at the junction of the Stuart and Victoria highway, the major road to WA. Tourism is a major industry based on attractions such as Nitmiluk National Park, injecting an average of $65million a year into the region.
Katherine is the centre of a fertile agricultural district, with large-scale cattle and crop production ventures. Regional fruit and vegetable production is worth around $40 million a year.
Another growth area is defence. RAAF Tindal, near Katherine is home to a community of 2,400 RAAF personnel and their families. Significant defence force spending, along with the regional surge in tourism, mining and horticulture, has contributed to Katherine's strong growth of 60% over a 10 year period to 1998.
Katherine provides a range of services including retailing, educational, sporting, health facilities including a hospital and community health centre.
For more information refer to the Northern Territory Government site: http://www.nt.gov.au/ntg_internet/profile/regions_katherine.shtml
Katherine has a significant Aboriginal population and is an important service centre for Aboriginal communities in surrounding areas including south-western Arnhem Land. Aboriginal communities within the bioregion include Maranboy.
The bioregion is within the ATSIC region of Jaburi (McLennan, 1997). The Northern Lands Council has a regional office in Katherine. 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
- 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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