Mulga | |
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Fabales |
Family: | Fabaceae |
Subfamily: | Caesalpinioideae |
Clade: | Mimosoid clade |
Genus: | Acacia |
Species: | A. aneura |
Binomial name | |
Acacia aneura | |
Occurrence data from AVH |
Acacia aneura, commonly known as mulga or true mulga, is a shrub or small tree native to arid outback areas of Australia. It is the dominant tree in the habitat to which it gives its name (mulga) that occurs across much of inland Australia. Specific regions have been designated the Western Australian mulga shrublands in Western Australia and Mulga Lands in Queensland.
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Mulga trees are highly variable, in form, in height, and in shape of phyllodes and seed pods. They can form dense forests up to 15 metres (49 ft) high, or small, almost heath-like low shrubs spread well apart. Most commonly, mulgas are tall shrubs. Because the mulga is so variable, its taxonomy has been studied extensively, and although A. aneura is likely to be split into several species eventually, there is as yet no consensus on how or even if this should be done[ citation needed ]. Although generally small in size, mulgas are long-lived, a typical life span for a tree undisturbed by fire is of the order of 200 to 300 years.
Mulga has developed extensive adaptations to the Australian desert. Like many Acacia species, it has thick-skinned phyllodes. These are optimised for low water loss, with a high oil content, sunken stomata, and a profusion of tiny hairs which reduce transpiration. During dry periods, mulgas drop much of their foliage to the ground, which provides an extra layer of mulch and from where the nutrients can be recycled.
Like most Australian Acacia species, mulga is thornless. [2] The needle-like phyllodes stand erect to avoid as much of the midday sun as possible and capture the cooler morning and evening light. Any rain that falls is channelled down the phyllodes and branches to be collected in the soil immediately next to the trunk, providing the tree with a more than threefold increase in effective rainfall. Mulga roots penetrate far into the soil to find deep moisture. The roots also harbour bacteria that fix atmospheric nitrogen and thus help deal with the very old, nutrient-poor soils in which the species grows.
Aboriginal peoples of the Coober Pedy area in South Australia refer to mulga trees as Umoona, which means "long life". [3]
Mulga savanna and mulga codominant tussock grasslands cover roughly 20% of the Australian continent, or about 1.5 million square kilometres. The mean rainfall for much of the habitat for A. aneura in Australia is roughly 200–250 mm/year, but it goes to as high as 500 mm/year in New South Wales and Queensland. The lowest mean rainfall where it grows is about 50–60 mm/year. [4] Both summer and winter rainfall are necessary to maintain mulga, and the species is absent from semiarid regions that experience summer or winter drought. [5]
Mulga scrub is distinctive and widespread, with the Mulga Lands of eastern Australia defined as a specific bioregion. The dominant species in these woodlands is mulga, with poplar box ( Eucalyptus populnea ) forming an increasingly important codominant in the eastern districts. [6] [7] The extent of ground cover in mulga woodlands varies with canopy density of the overstorey, becoming almost nonexistent in extremely dense stands. In more open stands, the herbaceous layer consists of wire grasses ( Aristida spp.)mulga is long-lived, mulga oats ( Monocather sp.), mulga mitchell ( Thyridolepis sp.), wanderrie ( Eriachne spp.), finger grasses ( Digitaria spp.) and love grasses ( Eragrostis spp.). Various other woody species are also significant in mulga woodlands, particularly hop bushes ( Dodonaea spp.), Eremophila and cassia ( Senna spp.). [5] [7]
In contrast to the eucalypt woodlands that dominate much of Australia, mulga woodlands are not well adapted to regular fire and species in mulga communities vary in their ability to survive fires. [8] [9] Many species, including mulga, have a very limited ability to resprout after fire, and rely instead on mechanisms of seed production for species survival. Many plants produce hard, woody fruits or seeds, which can not only survive intense heat, but also may require the stimulus of fire to scarify and promote germination. Long-lived seed stores in soil is also common in these woodlands. [9] [10] [11]
The recognised varieties are:
Mulga can be planted with sandalwood in plantations as a host tree. The tree's flowers provide forage for bees, especially when there is enough water available. [12]
Mulga is of great economic importance to the Australian pastoral industry. Despite containing considerable amounts of indigestible tannins, mulga leaves are a valuable fodder source, particularly in times of drought, as they are palatable to stock and provide up to 12% crude protein. [12]
The seeds of Acacia aneura are traditionally used to make seedcakes. The mulga apple is an insect gall commonly eaten by Aboriginal people. [13] Mulga tree gum (ngkwarle alkerampwe in the Arrernte language) is a type of lerp scale found on mulga branches. It provides a tasty, honey-like treat. [12]
Wood from Acacia aneura stands up very well to being buried in soil, so it is used for posts. The wood has a density of about 850–1100 kg/m3. [12] It is also good as firewood, and good-quality charcoal can be produced from it. [12]
Mulga is a vital tree to Aboriginal Australians in central and Western Australia; the wood is a good hardwood for making various implements, such as digging sticks, woomeras, shields and wooden bowls. [14]
Sclerophyll is a type of vegetation that is adapted to long periods of dryness and heat. The plants feature hard leaves, short internodes and leaf orientation which is parallel or oblique to direct sunlight. The word comes from the Greek sklēros (hard) and phyllon (leaf). The term was coined by A.F.W. Schimper in 1898, originally as a synonym of xeromorph, but the two words were later differentiated.
A savanna or savannah is a mixed woodland-grassland ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses. According to Britannica, there exists four savanna forms; savanna woodland where trees and shrubs form a light canopy, tree savanna with scattered trees and shrubs, shrub savanna with distributed shrubs, and grass savanna where trees and shrubs are mostly nonexistent.
Acacia brachystachya, commonly known as umbrella mulga, turpentine mulga or false bowgada, is a shrub in the family Fabaceae. The species occurs in mulga and heath communities on sandhills and rocky ridges in all mainland states of Australia, except Victoria.
Acacia kempeana, commonly known as wanderrie wattle, witchetty bush or granite wattle, is a shrub in subfamily Mimosoideae of family Fabaceae that is endemic to arid parts of central and western Australia.
Acacia ligulata is a species of Acacia, a dense shrub widespread in all states of mainland Australia. It is not considered rare or endangered. Its common names include sandhill wattle, umbrella bush, marpoo, dune wattle, small coobah, wirra, and watarrka.
The deserts of Australia or the Australian deserts cover about 2,700,000 km2 (1,000,000 sq mi), or 18% of the Australian mainland, but about 35% of the Australian continent receives so little rain, it is practically desert. Collectively known as the Great Australian desert, they are primarily distributed throughout the Western Plateau and interior lowlands of the country, covering areas from South West Queensland, Far West region of New South Wales, Sunraysia in Victoria and Spencer Gulf in South Australia to the Barkly Tableland in Northern Territory and the Kimberley region in Western Australia.
Acacia harpophylla, commonly known as brigalow, brigalow spearwood or orkor, is an endemic tree of Australia. The Aboriginal Australian group the Gamilaraay peoples know the tree as Barranbaa or Burrii. It is found in central and coastal Queensland to northern New South Wales. It can reach up to 25 m (82 ft) tall and forms extensive open-forest communities on clay soils.
Acacia ayersiana is a plant that grows in arid areas of Australia.
Acacia ayersiana var. latifolia is a plant that grows in arid areas of Australia.
Acacia stenophylla is a species of Acacia commonly referred to as the shoestring acacia. It is an evergreen tree in the family Fabaceae native to Australia. It is not considered rare or endangered.
The Mulga Lands are an interim Australian bioregion of eastern Australia consisting of dry sandy plains with low mulga woodlands and shrublands that are dominated by Acacia aneura (mulga). The Eastern Australia mulga shrublands ecoregion is coterminous with the Mulga Lands bioregion.
Acacia cana, or commonly named as boree or the cabbage-tree wattle or broad-leaved nealie, is part of the family Fabaceae and sub-family Mimosoideae. It is a dense shrub- tree that can grow to 6 metres (20 ft) high and is a perennial plant meaning it has long life span and doesn’t necessary produce a high amount of seed. The cabbage-tree wattle heavily flowers from August till October and relies on animals and insects for pollination and dispersal of seeds. This least concern acacia species is found in the western plains of New South Wales and Central Queensland the habitats of these areas are found to be sandy soils and gibber plains.
Acacia aptaneura, commonly known as slender mulga, is a shrub belonging to the genus Acacia and the subgenus Juliflorae. It is native to central and western parts of Australia.
Acacia fuscaneura, commonly known as sooty wattle, is a tree belonging to the genus Acacia and the subgenus Juliflorae. It is native to arid areas of central Australia.
Acacia minyura is a tree or shrub belonging to the genus Acacia and the subgenus Juliflorae endemic to arid parts of central Australia.
Acacia paraneura, commonly known as weeping mulga, is a tree or shrub belonging to the genus Acacia and the subgenus Juliflorae. It is native to arid regions of Australia. The Indigenous Kurrama peoples know the tree as warlun.
Acacia ramulosa, commonly known as horse mulga or bowgada wattle, is a shrub belonging to the genus Acacia and the subgenus Juliflorae endemic to arid areas of Australia.
Acacia wanyu, commonly known as wanyu or silver-leaf mulga, is a shrub or tree belonging to the genus Acacia and the subgenus Juliflorae that is endemic to arid parts of western Australia. The Kurrama people know it as Murruturu or Yirritiri while the Nyangumarta people know it as Wayartany.
Acacia calcicola is a shrub or tree of the genus Acacia and the subgenus Plurinerves that is native to parts of central Australia. Common names for this species include; shrubby wattle, shrubby mulga, myall-gidgee, northern myall and grey myall. Indigenous Australians the Pitjantjatjara peoples know the tree as ikatuka, the Warlpiri know it as jirlarti and the Arrernte know it as irrakwetye.
Mulga is a type of habitat composed of woodland or open forest dominated by the mulga tree, Acacia aneura, or similar species of Acacia.