Pilbara

The Pilbara subegion of the WA rangelands covers an area larger than 500,000 square kilometres and has about 4,665 kilometres of coastline. It is bordered by the Gascoyne subregion in the south, the Kimberley subregion in the North, the Indian Ocean to the west and the Desert Rangelands to the east.

According to the Australian Bureau of Statistics, 48,610 people lived in the Pilbara in 2010.

History and Economy

Aboriginal people have lived in the Pilbara for more than 30,000 years and the many different indigenous groups of the region call it Bilybarra, which means ‘dry country’. In 1818, Captain Philip Parker King arrived in the Dampier Archipelago, he was later followed by Francis Thomas Gregory who arrived in 1861 at Nickol Bay on the ‘Dolphin’. Francis Thomas Gregory named Hearson’s Cove, the Maitland and Fortescue rivers, the Hamersley Ranges, and Mts Samson and Bruce.

Today the major towns of the Pilbara are Karratha, Roebourne, Onlsow, Port Hedland, South Hedland, Newman and Tom Price. The main economic activities of the region include mining, petroleum, pastoralism and tourism.

Some of the most significant mineral resources being mined in this region are iron ore, salt, molybdenum, manganese, gold, copper, tantalite, silver, lead and zinc. A significant portion of the Pilbara is under mining tenement although only a small portion is directly subjected to exploration and mining activities. Currently more than 95% of Australia’s iron ore exports come from the Pilbara. The Pilbara has the largest solar salt fields in Australia and the second largest in the world. As well this subregion has a large proportion of Australia’s hydrocarbon reserves making it the major gas-processing hub of the nation.  The Pilbara also produces oil and gas products such as fertiliser and industrial products such as those from the world’s largest ammonia plant, opened on the Burrup Peninsula in April 2006.

The majority of the subregion (58 per cent) is under pastoral leasehold tenure, with leases being between 200,000 and 300,000 hectares, although smaller on the more productive coastal areas. Before the economy boom in the 1960s, pastoralism was the main industry in the Pilbara, this was until settlers realised that the environmental conditions of the region were generally unfavourable for crops.

The Pilbara is valued by the tourists for the variety of recreational experiences, wilderness experiences and scenic views it provides. Key draw cards are the region’s natural assets e.g. Karijini and Millstream-Chichester National Parks.

Natural Environment

Climate

The Pilbara has a semi-arid to arid climate that is characterised by high temperatures, low and variable rainfall and high evaporation. Between the months of October and April temperatures exceed or reach 32°C almost every day and the average maximum temperature is often over 40°C. In the winter months the average temperature falls to 25°C. Inland the temperatures are generally higher due to the absence of a cooling sea breeze.

The average annual rainfall of the Pilbara subregion ranges from about 200 to 350 mm per year, however, the rainfall can vary widely from year to year. Most of the rain falls in the summer months between December and March but can continue through until June. This is followed by a pronounced dry period between August and November. The average yearly evaporation is about 2,500 mm; this exceeds the average yearly rainfall and is consistent throughout the year.

The coast from Port Hedland to Exmouth Gulf is the most cyclone prone area in Australia, with three to four tropical cyclones expected every year.

Rivers

The major river systems of the Pilbara are the Fortescue System, and the De Grey and Lesser rivers off the Northern divide of the Chichester Range. Along many of the region’s rivers e.g. the Fortescue and Oakover rivers, rock holes, gorges, grassy floodplains and wooded riparian areas occur. Intermittent systems like the Fortescue and Oakover rivers drain the Hamersley Ranges, the largest mountain range in Western Australia.

Wetlands

Six Pilbara wetlands have been identified as being of national significance, for example, Fortescue Marsh and Millstream Pools. A further 12 have been identified as being of regional significance.

Coastline

The Pilbara coastline is characterised by deltas like the De Grey River delta, barrier islands and lagoons with extensive mangroves, wide tidal mudflats like the Roebourne Plains and long stretches of sandy beaches or rocky shorelines.

The Dampier Archipelago has pristine reefs with islands that are virtually untouched. Some of the marine areas within the region, like the Dampier Archipelago, are considered to be the most biologically diverse in the state.

Flora and Fauna

The Department of Environment and Heritage identified the Hamersley-Pilbara area as one of the 15 biodiversity hotspots of Australia. This region provides habitat for a number of threatened, endemic and fire sensitive species and communities e.g. the ghost bat, mulgara and spectacled hare-wallaby.

This Pilbara contains one threatened ecological community, two species of Declared Rare Flora (DRF), 30 Priority One Flora, 23 Priority 2 Flora, seven Schedule One mammals, two Schedule One birds, one Schedule One reptile and five Schedule Four Fauna.

The Pilbara has one Ramsar listed wetland site which is located on the very southern edge of Eighty Mile Beach, as well as 15 wetlands of national significance, 33 wetlands of subregional significance and aquifers that support endemic stygofauna.

Vegetation

Arid grasses and shrubs are found widely throughout the Pilbara subregion. Hummock grasslands are the most extensive vegetation type; as well there are significant areas of tussock grassland, acacia woodland and open woodland. Smaller areas of chenopod shrubland and eucalypt woodland occur primarily on floodplains and along drainage lines. The coastal strip consists of grasslands and low open woodlands and the coastal flats have mangroves scrub.

IBRA Subregions

The Pilbara contains one IBRA sub-region, named Pilbara. To read more about IBRA subregions, and to access the Australian Government’s detailed descriptions of each, visit the Department of the Environment and Energy.