- Follows the coast from north of Onslow to near Pardoo in Western Australia.
- Vast coastal plains and inland mountain ranges with cliffs and deep gorges.
- Arid to tropical climate.
- The major population centres are Port Hedland, Newman (pop. 5,500) and Tom Price.
- The bioregion comprises Aboriginal land and leasehold land, and conservation reserves.
- Provides the majority of the state's exports in petroleum, natural gas and iron ore.
Statistical Local Areas
The Pilbara is an arid and tropical land with red mountain ranges dotted with white-trunked gums, with cliffs and deep gorges, by plains of spinifex, and island spangled blue seas, with colourful reefs that almost reach the coastline. It is an area were Aboriginal people have lived for more than 30,000 years resulting in a rich legacy of rock art. The Pilbara also features a number of significant national parks. The Pilbara depends on its mineral wealth and related industries.
The Pilbara bioregion which adjoins the coast in north-western Western Australia (to the north of the tropic of Capricorn) should not be confused with the larger region commonly known as the Pilbara, which is one of the 10 statistical and planning regions in WA. This larger region (510,300 sq kms in area) includes the Pilbara bioregion which is 178,500 sq kms in area (Thackway & Creswell 1995), but also extends from the coast to the Western Australian / Northern Territory border (Geographer focus on the Pilbara region). The Pilbara Statistical region includes parts of the bioregions of Great Sandy Desert, Little Sandy Desert and the Gibson Desert
The population of the Pilbara is around 45,000, and it has been declining over the last decade primarily due to restructuring within the mineral resources sector. The major population centres are Port Hedland / South Hedland (pop. 13,300), Karratha (pop. 9000), Newman (pop. 5,500), Tom Price (pop. 3,900), Paraburdoo (pop. 2,000), Roebourne (pop. 1,600). There are also a number of Aboriginal communities scattered across the region, with resident populations of between 50 - 300 people (The Pilbara people).
The Pilbara bioregion includes the Local Governments of the Town of Port Hedland, Shire of Roebourne, Shire of Ashburton, and part of the Shire of East Pilbara.
The Pilbara has an arid climate, which is influenced by two air masses over the region, the Indian Tropical Maritime air moving in from the west or north-west, and the tropical continental air from the inland.
During the warmer part of the year, there is a hot low-pressure system over the region resulting in clear skies and very high temperatures from November to February, with average maximum temperatures often over 40° C. During the winter months the average maximum temperature falls to about 25° C. Temperature ranges are generally greater in inland areas away from the moderating effects on onshore winds common in coastal areas.
The Pilbara lies south of the area normally penetrated by the north west monsoon in the summer months, and is only occasionally influenced by weather systems of the westerly circulation in the winter months. Rainfall is therefore low and variable.
Average rainfall over the area ranges from about 200mm to 350mm, although rainfall may vary widely from the average from year to year. Most of this rain falls between December and March, but continuing through until June, with a pronounced dry period between August and November.
The average yearly evaporation (about 2,500mm) exceeds average yearly rainfall. This is consistent throughout the year
The area is subject to occasional tropical cyclones, usually between January and April, with a frequency of about seven every of decade. Tropical cyclones contribute 40% - 60% of the north coastal rainfall, reducing to less than 30% to the south and east of the region.
Climate averages are available for Wittenoom: http://www.bom.gov.au/climate/map/climate_avgs/a5.shtml.
Several weather stations lie within the region. For monthly rainfall and temperature graphs refer to Bureau of Meteorology: www.bom.gov.au/climate/forms/map_forms/new_imagemaps/wa_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 Pilbara bioregion for this year and previous years can be found at: http://www.ea.gov.au/land/monitoring/ttrace/pil.html.
The Pilbara includes vast coastal plains and inland ranges. It contains some of the earth's oldest rock formations and important mineral deposits, which are thought to be around 3.5 billion years old.
There are four major geological components of the Pilbara bioregion (Thackway & Cresswell, 1995). The Hamersley Range, which is a mountainous area of Proterozoic (545-2500 million years ago) sedimentary ranges and plateaux. The Fortescue Plains consists of alluvial plains and river frontages. The Chichester range comprises Archaean (2500+ million years ago) granite and basalt plains. Roebourne consists of Quaternary (less than 10 million years ago) alluvial plains
The Chichester Range runs roughly east west, and provides a major catchment divide. This is a greatly undulating plateau and forms a watershed between the north-flowing river systems (including the Harding, Maitland, Yule, Turner and De Grey) and the westerly flowing Fortescue River (to the south of the Chichester Range). The headwaters of the north flowing rivers have dendritic drainage patterns and on large flat plains. On the southern flank of the Chichester range, the drainage pattern changes from dendritic to parallel. The streams are short and end on the alluvial plain of the Fortescue River Valley.
The drainage lines on the northern flanks of the Hamersley are parallel, short, and have steep gradients, which terminate in large outwash fans. Further south on the plateau, the patterns are dendritic with frequently interrupted drainage lines. The plains on the plateau act as internal drainage basins, holding large volumes of water after cyclonic rains.
Cyclones cause major flows in a number of rivers almost every year between December and April. The rivers are generally dry between August and November, with only occasional short-lived flows. Localised river flows may be sustained by small spring discharges from aquifers intersected by river channels.
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, Western Australia: www.dme.wa.gov.au/geology,
Most of the area consists of immature desert soils. The rocks in the region are very old consisting of granite domes, lateritised caps and volcanic and sedimentary rocks.
For further information on soils refer to the Digital Atlas of Australian Soils at: www.brs.gov.au/data/datasets/atlas/index.html
Arid grasses and shrubs are found widely over the region. Due to the variable rainfall, grasses are adapted to long periods of drought. One adaptation is for these grasses to grow in hummocks, up to a metre in diameter. The coastal strip consists of grasslands and low open woodlands. Coastal flats have fringing mangroves scrub. High shrublands and low woodlands occur along major river valleys and southern flanks of the Hamersley Range (Anon. 1989). Eucalypts are one of the most conspicuous plant groups. Over thirty species have been recorded in the Pilbara. They range in size from trees of 20 metres to multi-stemmed shrubs or mallees of up to about three metres tall.
The river red gum (Eucalyptus camaldulensis) occupies the banks of rivers and major watercourses along with coolibah (Eucalyptus coolabah). Snappy gum (Eucalyptus leucophoia) is restricted to hilltops. The kingsmill's mallee (Eucalyptus kingmillii) is found on the mountain tops of the Hamersley ranges. This grows only to about three metres and has distinctive red buds and young fruit.
Wattles (Acacia spp.) are also a conspicuous part of the Pilbara's arid landscape. There are more than 50 different species in the Pilbara, including a number of rare species, with two confined to the Hamersley Ranges and another confined to the Nullagine area. Most have a shrub or tree type habit. Other perennial shrubs include sennas, with their yellow buttercup flowers, holly leafed grevillea (Grevillea wickamii) and native fushias. After rain the Pilbara comes alive with new shoots on perennial shrubs, as well as a mass of annual seedlings emerging through the spinifex.
The sturt desert pea (Swainsona formosus) and the purple mulla mulla (Ptilotus exaltatus) are vigorous colonisers of disturbed soils. Scattered amongst the rocks and boulders are native gourds, with their white feathery flowers, and the northern bluebell (Trichodesma zeylanicum). The coastal caper (Capparis spinosa), and the dampier pea (Swainsona pterostylis) with its pink flower spikes, are commonly found on sandy coastal areas.
Vegetation communities vary across the Pilbara according to the type of landform. The mountainous Hamersley Range supports mulga low woodland over bunch grasses on fine textured soils and snappy gum over Triodia brizoides on skeletal sandy soils of the ranges. In the Hamersley Range, gorge vegetation of Callitris columellaris, Ficus platypoda, Brachychiton sp. and Dodonaea spp. grow.
The Fortescue Plains support salt marsh, mulga-bunch grass and short grass communities on alluvial plains. River Gum woodlands fringe the drainage lines. This is the northern limit of mulga (Acacia aneura). The Chichester Range supports shrub steppe characterised by Acacia pyrifolia over Triodia pungens hummock grasses. Snappy Gum tree steppes occur on ranges.
Roebourne component consists of a grass savanna of mixed bunch and hummock grasses, and dwarf shrub steppe of Acacia translucens over Triodia pungens. Samphire, sporobolus and mangal occur on marine alluvial flats (Thackway & Cresswell, 1995). The Dampier Archipelago contains more than 288 species of plants. The rare plant Helichrysum oligochaetum is listed as from the region. The Millstream Pools area supports the endemic millstream fan palm (Livistona alfredii) (Morton, et. al., 1995).
For detailed vegetation description refer to Beard, (1990). A list of threatened flora is available at the CALM website: www.calm.wa.gov.au/plants_animals/index.html.
National Parks such as Karijini National Park are home to a variety of birds, red kangaroos and euros, rock-wallabies, echidnas and several bat species. Geckos, goannas, dragons, legless lizards, pythons and other snakes are abundant. Huge termite mounds are a feature of the landscape and the rock piles of the rare pebble mound mouse may be found in spinifex country. Black footed rock wallabies are found in gorge country.
In terms of rare and threatened species, there is a reintroduced population of burrowing bettong (Bettongia lesueur), which is an endangered species on Boodie Island. Other vulnerable ANZECC-listed species in the area include the barrow Island euro (Macropus robustus isabellinus), black-footed rock-wallaby (Petrogale lateralis), mulgara (Dasycercus cristicauda), bilby (Macrotis lagotis), pebble-mound mouse (Pseudomys chapmani), ghost bat (Macroderma gigas), barrow island black-and-white fairy wren (Malurus leucopterus edouardi) and the skink (Ctenotus angusticeps), which is known only from Airlie Island.
Regionally endemic species include the red-eared Antechinus (Dasykaluta rosamondae), pilbara ningaui (Ningaui timealeyi), the pebble mouse, as well as numerous reptiles including the geckos (Diplodactylus savagei, D. wombeyi), and (Nephrurus wheeleri cinctus), the python (Liasis olivaceus barroni) and the goanna (Varanus pilbarensis).
Relict populations include the spectacled hare-wallaby (Lagorchestes conspicillatus conspicillatus), golden bandicoot (Isoodon auratus barrowensis), and brush-tailed possum (Trichosurus arnhemensis) on Barrow Island. The frog (Pseudophryne douglasi) is confined to seeps or shaded gorges in the Pilbara and North-west Cape. Abydos-Woodstock Reserve has one of the richest reptile assemblages yet recorded in arid Australia. Migratory waders, shorebirds and seabirds use the beaches and mudflats of the mangroves on islands of the Dampier Archipelago.
For a list of threatened fauna refer to CALM website: www.calm.wa.gov.au/plants_animals/index.html.
The Pilbara consists of a mixture of Aboriginal freehold and leasehold reserve, national parks and nature conservation reserves and crown land consisting of a variety of pastoral and mining leases. There is a low proportion of freehold land.
The first Europeans to stay in the Pilbara were seeking their fortunes in the gold mines in the early 1800's. The promise of pastoral prosperity and the hope of striking it rich with gold and minerals gathered together a melting pot of creed and colour; European settlers, Afghan camel drivers, Chinese miners, Japanese pearlers and tribal Aboriginals who laboured for them (see: http://www.pdc.wa.gov.au/region/history.htm>.)
The Pilbara region now makes a significant contribution to Western Australia's economy by providing the overwhelming majority of the state's three largest exports, petroleum, natural gas and iron ore. Gold mining is also an important industry.
In 1997/98 the value of the Pilbara's petroleum and mining industries exceeded $9 billion. While these industries dominate the region's economy, accounting for almost 90% of its investment and approximately 30% of its employment, other industries also make an important contribution. These include pastoralism in the form of extensive cattle grazing, fishing, aquaculture and pearling, salt extraction, tourism public administration, commercial services, construction and manufacturing.
Other important land uses include Aboriginal owned land and nature conservation. National Parks include Karijini National Park Millstream/Chichester National Parks, and the Dampier Archipelago. Spectacular examples of Aboriginal rock art are found throughout the Pilbara.
The dominant condition of the land is natural ecosystems co-existing with pastoral and mining activities. There has been significant land degradation throughout the Pilbara due to over grazing, introduction of weeds and feral animals and the extinction of many small mammals (Woinarski, et. al., in prep.).
Mining activity, including exploration, mining and transport has also resulted in impacts on the landscape. Although the modern mining industry is more conscious of reducing environmental impacts, the large scale of operations means that there are inevitable impacts on the landscape.
There has been impact in coastal areas including islands with port development and the construction of causeways linking islands to the mainland.
Foxes and cats are widespread, including on some offshore islands. Feral donkeys, camels and goats have contributed to land degradation. Localised weed infestations include buffel grass (Cenchrus ciliaris) (Woinarski, et. al., in prep.).
The population of the Pilbara is generally highly mobile due to the nature of the mining industry. There are more males than females (56% male as opposed to 49% for the State of WA as a whole). This trend is far more pronounced amongst the non-indigenous population. The population is generally young, with a higher proportion of 25 to 40 year olds, and a much lower proportion of over 60 year olds than the Western Australian state average.
The Aboriginal population makes up to around 10% of the population, with up to a third of this population speaking an Australian indigenous language. The bioregion lies within the ATSIC region of South Hedland and is managed by the regional council of Ngarda-Ngarli-Yamdu (McLennan, 1997). For more information on the Aboriginal people of this region refer to Horton, (1994) and the relevant websites in the reference list.
The mining industry plays an important role in the provision of services. There has been a trend for closed mining towns, previously under the control of mining companies, to become more open. This allows for land to be bought and sold and for more private enterprise in the provision of housing and shops. Eg Newman, Tom Price and Paraburdoo.
Mining towns in the Pilbara offer a wide range of sport and recreation opportunities. Land Conservation District Committees play a role in involving pastoral communities in Land Management. The bioregion is within the Kimberley Development Commission. For more information on the region refer to: http://www.kimberley.wa.gov.au.
Anon. 1989, Geographer Focus on: the Pilbara Region, Geographer Focus Series, Carlson Marsh, Marylands, Western Australia.
Beard, J. S. 1990, Plant life of Western Australia. Kangaroo Press, Kenthurst, New South Wales.
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.
Masini, R. J. 1988, Inland Waters of the Pibara, Western Australia - Part 1: a report of a field study carried out in march -April 1983, Technical Series 10, Environmental Protection Authority, Perth, Western Australia.
McLennan, W. 1997, 1994 National Aboriginal and Torres Strait Islander Survey: Social Atlas, Australian Bureau of Statistics, Canberra, ACT.
Morton, S. R., Short, J. & Barker, R. D. with an Appendix by Griffin, G. F. & Pearce, G. 1995, Refugia for Biological Diversity in Arid and Semi-arid Australia, Department of the Environment, Sport and Territories, Canberra, 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, ACT.
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.
Aboriginal languages of Australia:
Aboriginal Studies WWW Virtual Library:
Aboriginal and Torres Strait Islander Commission (ATSIC):
Australian Geological Survey Organisation, Geology of Australia:
Bureau of Meteorology, Climate averages:
Bureau of Meteorology, temperature/rainfall graphs:
Bureau of Rural Sciences, Digital Atlas of Australian Soils:
Conservation and Land Management (CALM), Drysdale River National Park:
Conservation And Land Management. Threatened plant and animal information:
Department of Mines and Energy, Western Australia, Geology of Western Australia:
Environment Australia, Normalized Difference Vegetation Index (NDVI) information including bioregional information:
Handbook of Western Australian Aboriginal Languages, South of the Kimberley.
Kimberley Development Commission:
Noongar Land Council: Related Website and Contacts of Aboriginal organisations:
Pilbara Physical Profile:
The Pilbara People:
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