Granite outcrops of Western Australia are weathered landforms that occur throughout the state of Western Australia, composed primarily of the rock type granite. All recognised types of this landform can be observed, commonly as bornhardts, but also as inselbergs, castle koppies and nubbins. Rising abruptly from the surrounding landscape they create a variety of microhabitats for plants, and provide seasonal resources and refuge for a range of animals. These areas thus have rich biodiversity and many endemicspecies. They are significant locations that tie in with the Aboriginal and European cultural heritage of Western Australia.
Granite outcrops in the state are ecologically complex and insular, often providing niches for ancient lineages of organisms that are relics of a wetter climate. These niches include unfractured rock surface that is covered in biofilm, composed of cyanobacteria that give massive rockfaces a characteristic colour. Crusts of lichens also appear, visible mats constructed by blue-green alga and fungal associations that may be up to a billion years old. Mats composed primarily of moss and spike-moss are also found when adequate moisture is available, which in turns provides opportunities for other organisms.[1] At least 1300 plant species occur on granite outcrops in Western Australia, many of which are endemic to these sites.[2] Some of these plant species gain a purchase a clefts and fissures in the rock face, and trees or large shrubs may appear in a bonsai-form.[3] Slabs of rock, split by exfoliation or cracked and pushed up to an A profile, form habitat that is cooler, damper, and secure for plant and animal species that are often specially adapted to the narrow environ.[4]
Pools of rainwater known as gnammas[5] often form on granite outcrops. These provide habitat to around 230 aquatic invertebrates, of which at least 50 are endemic to these pools,[6] and provide fresh water to other inhabitants and visitors.
Gnamma on Mount Melville, Albany
The flora of these granitic outcrops is notable in many regards. Woody species may include tall trees, eucalypts, sheoak, acacia, and rock figs of the genus Ficus, smaller species include these genera and taxa of verticordia, banksia, grevillea, and melaleuca. The number of orchid species occurring on them is 141, and 16% of these are endemic to these landforms. Those orchid species endemic to outcrops may be widely distributed or, as with Spiculaea ciliata, only found at locations separated by a few kilometres.[7]
Human use of the outcrops has been well documented,[8] and as a resource—for food and especially permanent water—they were often crucial to existence.
More recent material also provides useful information as to how to manage the environment of the rocks and their surroundings.[9][10][11]
Studies and conferences have also explored the natural history.[12][13] A number of animals are restricted to granite outcrops, including four species of reptile, the mygalomorphspiderTeyl luculentus, and the larvae of the chironomidflyArchaeochlus. They are also an important habitat of rock-wallabies such as the black-flanked rock-wallaby, and Ctenophorus ornatus, the ornate crevice-dragon.[14] Granitic outcrops also provide refuge for animals, as temporary protection against predation or seasonal habitat insulated from the extremes of weather.[13]
Great Southern region
Granite outcrops occur along the southern coast of the state, where they are exposed to high winds and extremes and wave and tidal action. They often form steep coastline, headlands and islands.[15]
↑ Hopper, S.D., Brown, A.P. and Marchant, N.G. (1997) Plants of Western Australian granite outcrops, Journal of the Royal Society of Western Australia, vol.80:141–158
↑ Main, Barbara (1 September 1997). "Granite outcrops: A collective ecosystem"(PDF). Journal of the Royal Society of Western Australia (80): 113–122. Retrieved 29 September 2008.
↑ Bayly, I.A.E. Rock of ages: human use and natural history of Australian granites Nedlands, W.A.: Tuart House, 1999. ISBN1-876268-29-8
↑ (1999) Managing granite outcrops for Western Australia / produced by the Revegetation on Farms Project, AGWEST, with input from CALM and the Royal Society of Western Australia. Narrogin, W.A.: Agriculture Western Australia ("A Project of the Sustainable Rural Development Program of Agriculture Western Australia, contributing to the Western Australian Salinity Action Plan")
↑ Hussey, B. M. J.(1998) 'How to manage your granite outcrops' Como, W.A.: Dept. of Conservation and Land Management, ISBN0-7307-1203-6 (pbk.)
↑ McMillan, Peter.(1990) Exploring granite outcrops written by Peter McMillan, illustrations by Margaret Pieroni, edited by Richard Grant and Carmel Staniland. Como, W.A: Dept. of Conservation and Land Management.
↑ Granite Outcrops Symposium, 14–15 September 1996.p.87–237. Journal of the Royal Society of Western Australia. vol.80, pt.3 (September 1997)
↑ Withers, P.C. and Edward D.H. (1997) Terrestrial fauna of granite outcrops in Western Australia, Journal of the Royal Society of Western Australia, vol.80:159–166
Wave Rock is a natural rock formation that is shaped like a tall breaking ocean wave. The "wave" is about 15 m (49 ft) high and around 110 m (360 ft) long. It forms the north side of a solitary hill, which is known as "Hyden Rock". This hill, which is a granite inselberg, lies about 3 km (2 mi) east of the small town of Hyden and 296 km (184 mi) east-southeast of Perth, Western Australia. Wave Rock and Hyden Rock are part of a 160 ha (395-acre) nature reserve, Hyden Wildlife Park. More than 100,000 tourists visit every year.
Stephen Donald Hopper AC FLS FTSE is a Western Australian botanist. He graduated in Biology, specialising in conservation biology and vascular plants. Hopper has written eight books, and has over 200 publications to his name. He was Director of Kings Park in Perth for seven years, and CEO of the Botanic Gardens and Parks Authority for five. He is currently Foundation Professor of Plant Conservation Biology at The University of Western Australia. He was Director of the Royal Botanic Gardens, Kew from 2006 to 2012.
The Dryandra Woodland is a national park in Western Australia within the Shires of Cuballing, Williams and Wandering, about 164 kilometres south-east of Perth and 22 kilometres north-west of the town of Narrogin. It is a complex of 17 distinct blocks managed by the Western Australian Department of Parks and Wildlife and spread over approximately 50 kilometres separated by areas of agricultural land. The area is considered to be one of the state's major conservation areas, and although it is far from pristine due to its history of logging operations, a number of species of threatened fauna are rebuilding populations through the removal of introduced predators such as foxes and feral cats.
Eucalyptus cornuta, commonly known as yate, is a tree species, sometimes a mallee and is endemic to the southwest of Western Australia. It has rough, fibrous bark on all or most of its trunk, smooth bark above, mostly lance-shaped adult leaves, elongated flower buds in groups of eleven or more, yellowish flowers and cylindrical to cup-shaped fruit. It is widely cultivated and produces one of the hardest and strongest timbers in the world.
The Avon Wheatbelt is a bioregion in Western Australia. It has an area of 9,517,104 hectares. It is considered part of the larger Southwest Australia savanna ecoregion.
Philippa Mary Nikulinsky is an artist and botanical illustrator based in Western Australia.
Kunzea pulchella, commonly known as granite kunzea, is a flowering plant in the myrtle family, Myrtaceae and is endemic to the south-west of Western Australia. It is a shrub with spreading branches, egg-shaped to lance-shaped leaves and loose groups of red flowers, each on a short stalk so that the branch is visible between the flowers.
Granitites intangendus is a species of flowering plant endemic to Western Australia. It is found on granite outcrops in semi-arid regions of the midwest and south.
Brachychiton gregorii, commonly known as the desert kurrajong, is a small tree of the genus Brachychiton found in northern and western Australia. It was originally classified in the family Sterculiaceae, which is now within Malvaceae.
Calothamnus rupestris, commonly known as mouse ears or granite net-bush, is a plant in the myrtle family, Myrtaceae and is endemic to the south-west of Western Australia. It is a shrub or small tree with short, stiff, prickly leaves and pink to red flowers in spring.
Kokerbin Rock, also known as Kokerbin Hill, is a granite rock formation located within Kokerbin Nature Reserve in the Wheatbelt region of Western Australia. The area has special significance for the Nyoongar. There are claims that Kokerbin Rock is the third largest monolith in Australia, with Mount Wudinna in South Australia being the second largest and Uluru in the Northern Territory being the largest.
Acacia lasiocalyx, commonly known as silver wattle or shaggy wattle, is a tree or shrub belonging to the genus Acacia and the subgenus Juliflorae.
Caladenia graniticola, commonly known as the Pingaring spider orchid, is a species of orchid endemic to the south-west of Western Australia. It has a single, hairy leaf and one or two yellowish-green, red and white flowers which have a greenish-yellow and white labellum with a red tip. It was originally described as Caladenia hoffmanii subsp. graniticola but has a slightly different labellum and column.
Caleana granitica, commonly known as the granite duck orchid is a species of orchid that is endemic to the south-west of Western Australia. It is a species of duck orchid with a single smooth leaf and a single greenish yellow and red flower with the labellum held below the horizontal. It grows on a single granite outcrop near Armadale.
Thelymitra granitora, commonly called the coastal granite sun orchid or coastal sun orchid, is a species of orchid in the family Orchidaceae and is endemic to the south-west of Western Australia. It has a single short, curved and channelled dark green leaf and up to eight relatively large pale blue or white, self-pollinating flowers with white mop-like tufts on the top of the anther.
Thelymitra petrophila, commonly known as the granite sun orchid, is a species of orchid that is endemic to Western Australia. It has a single erect, channelled, long light green leaf and up to ten or more pale blue to mauve or pink flowers. It grows in drier area, usually in shallow soil pockets on granite outcrops.
Yorkrakine Rock is a granite rock formation located approximately 25 km (16 mi) north of Tammin and 50 km (31 mi) south east of Dowerin in the eastern Wheatbelt region of Western Australia. It makes up part of the Yorkrakine Rock Nature Reserve and is located on the Tammin Wyalkatchem Road. It is about 10 km (6 mi) south of the old Yorkrakine townsite. The reserve has access roads and parking as well as toilets and picnic tables, but camping is not permitted.
Borya sphaerocephala is a perennial herbaceous plant found in southwest Australia. A common name for the species is pincushions. The height is 20–200 millimetres, White flowers appear between August and October. The species is associated with the region's granite outcrops, occurring in depressions and seasonally wet areas, growing in crevices and at the edge of moss mats. As a resurrection plant it is able to withstand seasonal dehydration of its environ. The species was first described by Robert Brown, published in his 1810 work on Australian plants. A combination Baumgartenia sphaerocephala, currently regarded as synonym, was published by Kurt Sprengel several years after Brown.
Lomandra rigida, commonly known as stiff mat rush, is a herbaceous perennial plant endemic to the southern coast of Southwest Australia.
Tetratheca phoenix is a species of flowering plant in the quandong family that is endemic to Australia.
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