page_title: Flora of Australia
section_title: Vegetation types
hierarchical_section_title: Flora of Australia / Vegetation types
caption_attribution_description: This is a photograph of Triodia hummock grasslands at Karijini National Park, Western Australia. The green hummocks are Triodia pungens R.Br. (Soft Spinifex); the blue-grey hummocks are Triodia basedowii E.Pritz. (Hard Spinifex or Lobed Spinifex). The trees in the background are Eucalyptus and Acacia species.
context_page_description: The flora of Australia comprises a vast assemblage of plant species estimated to over 20,000 vascular and 14,000 non-vascular plants, 250,000 species of fungi and over 3,000 lichens. The flora has strong affinities with the flora of Gondwana, and below the family level has a highly endemic angiosperm flora whose diversity was shaped by the effects of continental drift and climate change since the Cretaceous. Prominent features of the Australian flora are adaptations to aridity and fire which include scleromorphy and serotiny. These adaptations are common in species from the large and well-known families Proteaceae, Myrtaceae, and Fabaceae.
  The arrival of humans around 50,000 years ago and the settlement by Europeans from 1788, has had a significant impact on the flora. The use of fire-stick farming by Aboriginal people led to significant changes in the distribution of plant species over time, and the large-scale modification or destruction of vegetation for agriculture and urban development since 1788 has altered the composition of most terrestrial ecosystems, leading to the extinction of 61 plant species and endangering over 1000 more.
context_section_description: Australia's terrestrial flora can be collected into characteristic vegetation groups. The most important determinant is rainfall, followed by temperature which affects water availability. Several schemes of varying complexity have been created, the most recent scheme developed by the Natural Heritage Trust divides Australia's terrestrial flora into 30 Major Vegetation Groups, and 67 Major Vegetation Subgroups.
  According to the scheme the most common vegetation types are those that are adapted to arid conditions where the area has not been significantly reduced by human activities such as land clearing for agriculture. The dominant vegetation type in Australia is the hummock grasslands that occur extensively in arid Western Australia, South Australia and the Northern Territory. It accounts for 23% of the native vegetation, the predominant species of which are from the genus Triodia. Zygochloa also occurs in inland sandy areas like the Simpson Desert.
  A further 39% of native vegetation is covered by a combination of:
  Eucalypt woodlands found at the transition between hummock grasslands and higher rainfall areas where conditions still limit tree growth; the woodland may have a grass or shrubby understory. The largest area is in Queensland.
  Acacia forests and woodlands that occur in semi-arid areas where tree growth is stunted. The dominant Acacia species varies with the location, and may include lancewood, bendee, mulga, gidgee and brigalow. The largest area is in Western Australia.
  Acacia shrublands in semi arid and arid regions. The most common are mulga shrublands; the largest area is in Western Australia.
  Tussock grasslands that occur in semi-arid and some temperate parts of Australia; they host a large variety of grasses from more than 10 genera. The largest area is in Queensland.
  Chenopod/samphire shrubs and forblands that are widespread in the near-estuarine, arid and semi-arid areas. Species in chenopod communities are drought and salt tolerant and include the genera Sclerolaena, Atriplex, Maireana, Chenopodium and Rhagodia while samphire representatives include Tecticornia, Salicornia, Sclerostegia and Sarcocornia. Both South and Western Australia have large areas with this vegetation type.
  Other groups with restricted areas of less than 70,000 square kilometres include tropical or temperate rainforest and vine thickets, tall or open eucalypt forests, Callitris and Casuarina forests, and woodlands and heath.
caption: Hummock grassland, the green hummocks are Triodia pungens and the blue-grey hummocks are Triodia basedowii.
exif: {}