Flora of Australia

Source: Wikipedia, the free encyclopedia.
For the series of monographs, see Flora of Australia (series).
"Australian plants" redirects here. For the magazine, see
Australian Plants
.
Victoria. Australia's tree flora is dominated by a single genus, Eucalyptus, and related Myrtaceae.[1]
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The flora of

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 (Banksia), Myrtaceae (Eucalyptus - gum trees), and Fabaceae (Acacia
- wattle).

The arrival of humans around 50,000 years ago

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 by 2006, and endangering over 1000 more.

Origins and history

The Tasmanian rainforest is considered a Gondwanan relic.
Main article: Natural history of Australia

Australia was part of the southern supercontinent Gondwana, which also included South America, Africa, India and Antarctica. Most of the modern Australian flora had their origin in Gondwana during the Cretaceous when Australia was covered in subtropical rainforest. Australian ferns and gymnosperms bear a strong resemblance to their Gondwanan ancestors,[4] and prominent members of the early Gondwanan angiosperm flora such as the Nothofagus, Myrtaceae and Proteaceae were also present in Australia.[5]

Scrubland with Xanthorrhoea following bushfire.

Gondwana began to break up 140 million years ago (MYA); 50 MYA during the

South-east Asian and cosmopolitan elements entering the flora like the Lepidium and Chenopodioideae.[7]

A riparian zone with casuarina and eucalyptus species in Sydney.

The development of aridity and the old and nutrient poor soils of the continent led to some unique adaptations in the Australian flora and evolutionary radiation of genera – like

outer layer, a condition known as scleromorphy, and C4 and CAM
carbon fixation which reduce water loss during photosynthesis are two common adaptations in Australian arid-adapted dicot and monocot species respectively.

Rising aridity also increased the frequency of fires in Australia. Fire is thought to have played a role in the development and distribution of fire-adapted species from the Late Pleistocene. An increase in charcoal in sediment around 38,000 years ago coincides with dates for the inhabitation of Australia by the Indigenous Australians and suggests that man-made fires, from practices like fire-stick farming, have played an important role in the establishment and maintenance of sclerophyll forest, especially on the east coast of Australia.[8] Adaptations to fire include lignotubers and epicormic buds in Eucalyptus and Banksia species that allow fast regeneration following fire. Some genera also exhibit serotiny, the release of seed only in response to heat and/or smoke. Xanthorrhoea grass trees and some species of orchids only flower after fire.[9]

Biogeography

In biogeography and zoogeography, Australia alone is sometimes considered a realm (Australian realm), while some authors unite the area with other regions to form the Australasian realm.

In phytogeography, the area is considered a floristic kingdom (Australian kingdom), with the following endemic families, according to Takhtajan: Platyzomataceae (now included in

Leptospermoideae) and Proteaceae.[10][11]

Vegetation types

Major vegetation groups in Australia from the 2009 Atlas of Australian Resources
Hummock grassland, the green hummocks are Triodia pungens and the blue-grey hummocks are Triodia basedowii.

Australia's terrestrial flora can be collected into characteristic

Major Vegetation Subgroups.[14]

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:

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.

Vascular plants

Australia has over 21,077 described species of vascular plants,

angiosperms, seed-bearing non-angiosperms (like the conifers and cycads), and the spore-bearing ferns and fern allies.[18] Of these about 11% are naturalised species; the remainder are native or endemic.[19] The vascular plant flora has been extensively catalogued, the work being published in the ongoing Flora of Australia series. A list of vascular plant families represented in Australia using the Cronquist system is also available.[20]

At the higher taxonomic levels the Australian flora is similar to that of the rest of the world; most vascular plant families are represented within the native flora, with the exception of the cacti, birch and a few others, while 9 families occur only in Australia.[21][22] Australia's vascular flora is estimated to be 85% endemic;[23] this high level of vascular plant endemism is largely attributable to the radiation of some families like the Proteaceae, Myrtaceae, and Fabaceae.

Angiosperms

Largest angiosperm families in Australia
Family % of total flora1 Notable genera
Fabaceae 12.0 Acacia, Pultenaea, Daviesia, Bossiaea
Myrtaceae 9.3 Callistemon, Eucalyptus, Melaleuca, Leptospermum
Asteraceae 8.0 Brachyscome, Olearia
Poaceae 6.5 Triodia
Proteaceae 5.6 Banksia, Hakea, Grevillea
Cyperaceae 3.3 Cyperus
Orchidaceae
 3.0 Caladenia, Pterostylis
Ericaceae 2.1 Leucopogon, Epacris
Euphorbiaceae 2.0 Ricinocarpos
Rutaceae 1.8 Boronia, Correa, Citrus
1 Based on total number of species

Data from Orchard modified to AGPII classifications.[18]

The native Australian flora contains many

orchid in Australia.[24] About one quarter of these are epiphytes. The terrestrial orchids occur across most of Australia, the majority of species being deciduous
– their aboveground parts die back during the dry season and they re-sprout from a tuber when it rains.

Other families with well-known representatives include the alpine Tasmanian button grass, which form tussock-like mounds from the Cyperaceae; the genus Patersonia of temperate iris-like forbs from the Iridaceae; and, the kangaroo paws from the family Haemodoraceae. The Xanthorrhoea grass trees, the screw palms of the Pandanaceae and palms are large monocots present in Australia. There are about 57 native palms; 79% of these only occur in Australia.[25]

The

golden wattle
.

Many plant families that occur in Australia are known for their floral displays that follow seasonal rains. The Asteraceae is well represented by its subfamily Gnaphalieae, which included the paper or everlasting daisies; this group has its greatest diversity in Australia. Other families with flowering shrubs include the Rutaceae, with the fragrant Boronia and Eriostemon, the Myoporaceae with the Eremophila, and members of the Ericaceae with Victoria's Floral Emblem Epacris impressa.

Senna odorata, a fabaceae native to eastern Australia

Amongst the most ancient species of flowering hardwood trees are the

Western Australian Christmas tree
.

Australia's salt marshes and wetlands are covered by a large variety of salt and drought tolerant species from the

Nepenthaceae
.

Aquatic monocots and dicots both occur in Australian waters. Australia has about 51,000 square kilometres of

mangroves; in Australia there are 39 mangrove species that cover 11,500 square kilometres and comprise the third largest area of mangroves in the world.[27] Other native aquatic dicots here include water lilies and water milfoils
.

Gymnosperms

Huon pine, sole member of the genus Lagarostrobos. Callitris is a notable exception; species from this genus are found mainly in drier open woodlands.[28] The most recently discovered species of conifer is the living fossil Wollemi pine, which was first described in 1994. Although many Australian conifers are referred to as 'pines', there are no members of the pine family (Pinaceae
) native to Australia.

Ferns and fern allies

Spore bearing vascular plants include the ferns and fern allies. True ferns are found over most of the country and are most abundant in tropical and subtropical areas with high rainfall. Australia has a native flora of 30 families, 103 genera and 390 species of ferns, with another 10 species being naturalised. The "fern allies" are represented by 44 native species of whisk ferns, horsetails and lycophytes.[28] Ferns prefer a cool and damp environment since water is required for reproduction, the majority of Australian species are found in bushland [clarification needed] and rainforest, there are aquatic, epiphytic (Platycerium, Huperzia and Asplenium), and terrestrial species including large tree ferns from the genera Cyathea and Dicksonia.

Non-vascular plants

The algae are a large and diverse group of photosynthetic organisms. Many studies of algae include the cyanobacteria, in addition to micro and macro eukaryotic types that inhabit both fresh and saltwater. Currently, about 10,000 to 12,000 species of algae are known for Australia.[29] The algal flora of Australia is unevenly documented: northern Australia remains largely uncollected for seaweeds and marine phytoplankton, descriptions of freshwater algae are patchy, and the collection of terrestrial algae has been almost completely neglected.[30]

The

bryophytes – mosses, liverworts and hornworts – are primitive, usually terrestrial, plants that inhabit the tropics, cool-temperate regions and montane areas; there are some specialised members that are adapted to semi-arid and arid Australia. There are slightly fewer that 1,000 recognised species of moss in Australia. The five largest genera are the Fissidens, Bryum, Campylopus, Macromitrium and Andreaea.[31] There are also over 800 species of liver- and horn-worts in 148 genera in Australia.[32]

Fungi

Main article: Fungi of Australia

The fungal flora of Australia is not well characterised; Australia is estimated to have about 250,000 fungal species of which roughly 5% have been described. Knowledge of distribution, substrates and habitats is poor for most species, with the exception of common plant pathogens.[33]

Lichens

Lichens are composite organisms comprising, in most cases, an Ascomycete fungus and a unicellular green alga, their classification is based on the type of fungi. The lichen flora of Australia and its island territories, including Christmas Island, Heard Island, Macquarie Island and Norfolk Island, currently comprises 3,238 species and infra-specific taxa in 422 genera, 34% of which are considered to be endemic.[34]

Use by humans

Solanum laciniatum

The first Australian plants recognised and classified in Linnaean taxonomy were a species of Acacia and Synaphea in 1768 as Adiantum truncatum and Polypodium spinulosum respectively by Dutch philologist Pieter Burman the Younger, who stated they were from Java. Later, both were found to be from Western Australia, likely to have been collected near the Swan River, possibly on a 1697 visit there of fellow Dutchman Willem de Vlamingh.[35] This was followed by Cook's expedition making landfall at what is now Botany Bay in April 1770, and the early work of Banks, Solander and Parkinson.[who?] Botanical exploration was enabled by the founding of the permanent colony at Port Jackson in 1788, and the subsequent expeditions along Australia's coastline.[35]

The Australian flora was utilised by the Indigenous inhabitants of Australia. Indigenous Australians used thousands of species for food, medicine, shelter, tools and weapons.[36] For example, the starchy roots of Clematis microphylla were used in western Victoria to make a dough that was baked, and the leaves of the plant were used as a poultice applied to skin irritations and blisters.[37]

Since European colonisation

Forestry species include a number of eucalypts used for paper and timber,

wallaby grass, spear grass, tussock grasses and kangaroo grass.[citation needed
]

Commercial use

Until recently the

scopolamine and hyoscyamine producing Duboisia species and Solanum aviculare and S. laciniatum for the steroid solasodine. Essential oils from Melaleuca, Callitris, Prostanthera, Eucalyptus and Eremophila
are also used medicinally. Due to the wide variety of flowers and foliage, Australian plant species are also popular for floriculture internationally.

Gymea Lily growing in Heathcote National Park
, Sydney.

Conservation

Main article: Conservation in Australia

Modification of the Australian environment by Indigenous Australians and following European settlement has affected the extent and the distribution of the flora.

Threats

The changes since 1788 have been rapid and significant: displacement of Indigenous Australians disrupted fire régimes that had been in place for thousands of years; forestry practices have modified the structure of native forests; wetlands have been filled in; and broad scale land-clearing for crops, grazing and urban development has reduced native vegetation cover and led to landscape salinisation, increased sediment, nutrient and salt loads in rivers and streams, loss of habitat and a decline in biodiversity.[40] The intentional and unintentional release of invasive plant and animal species into delicate ecosystems is a major threat to floral biodiversity; 20 introduced species have been declared Weeds of National Significance.[41]

Threatened plant biodiversity

As of 2006, 61 plant species were known to have become extinct since European settlement; and a further 1,239 species were considered threatened.[42]

Protected areas

Protected areas have been created in every state and territory to protect and preserve the country's unique ecosystems. These protected areas include national parks and other reserves, as well as 64 wetlands registered under the Ramsar Convention and 16 World Heritage Sites. As of 2002, 10.8% (774,619.51 km2) of the total land area of Australia is within protected areas.[43] Protected marine zones have been created in many areas to preserve marine biodiversity; as of 2002, these areas cover about 7% (646,000 km2) of Australia's marine jurisdiction.[44]

Biodiversity hotspots

In 2003, the Australian Government's Threatened Species Scientific Committee identified 15

Biodiversity Action Plan.[45][46]

See also

Region specific articles

References

Notes

  1. PMID 21326225
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  2. PMID 21940856
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  3. ISBN 1-876622-50-4
  4. ^ Page, C. N. and Clifford, H. T. 1981. Ecological biogeography of Australian conifers and ferns. In A. Keast Ecological Biogeography of Australia. W. Junk
  5. doi:10.1016/0034-6667(90)90064-p
    .
  6. ISBN 0-909209-62-6
  7. PMID 15519972
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  8. ^ Singh, G. et al. 1981. Quaternary vegetation and fire history in Australia. In A. M. Gill, R. A. Groves and I. R. Nobel. Fire and the Australian Biota. Australian Academy of Science, 23-54
  9. ^ Gill, A. M. 1981. Adaptive responses of Australian vascular plant species to fire. In A. M. Gill, R. H. Groves, and I. R. Noble. eds. Fire and the Australian Biota. Australian Academy of Science
  10. ^ Тахтаджян А. Л. Флористические области Земли / Академия наук СССР. Ботанический институт им. В. Л. Комарова. — Л.: Наука, Ленинградское отделение, 1978. — 247 с. — 4000 экз. DjVu, Google Books.
  11. ^ Takhtajan, A. (1986). Floristic Regions of the World. (translated by T.J. Crovello & A. Cronquist). University of California Press, Berkeley, PDF, DjVu.
  12. ^ Groves, R. H. 1999. Present vegetation types. In A. E. Orchard, ed. Flora of Australia - Volume 1, 2nd edition pp 369-401. ABRS/CSIRO
  13. Government of Australia
  14. ^ NVIS 6.0 Major Vegetation Subgroups (numeric order), Department of Climate Change, Energy, the Environment and Water, Government of Australia.
  15. ^ Australian National Botanic Gardens (2012). "Acacia Forests and Woodlands". Retrieved 20 January 2018.
  16. ^ Australian Government. Department of the Environment and Energy (2017). "NVIS Fact sheet. MVG 6 – Acacia forests and woodlands" (PDF). p. 4. Retrieved 20 January 2018.
  17. PMID 36913725
    .
  18. ^ a b Orchard, A. E. 1999. Introduction. In A. E. Orchard, ed. Flora of Australia - Volume 1, 2nd edition pp 1-9. ABRS/CSIRO
  19. ISBN 0-644-11606-4
  20. ^ Australian Biological Resources Study. Flora of Australia Online - What's published and online, contributors and dates of publication Archived 2006-12-14 at the Wayback Machine
  21. ^ Crisp, M. D., West, J. G., and Linder, H.P. 1999. Biogeography of the Australian flora. In A. E. Orchard, ed. Flora of Australia - Volume 1, 2nd edition pp 321-367. ABRS/CSIRO
  22. ^ Department of the Environment and Heritage. Australia's Biodiversity: an overview of selected significant components Archived 2006-09-06 at the Wayback Machine, Biodiversity Series, Paper No. 2
  23. ^ ESD Working Group on Biological Diversity. 1991. The Conservation of Biological Diversity as it Relates to Ecologically Sustainable Development, Report of Working Party to the Ecologically Sustainable Development Secretariat, Canberra.
  24. Association of Societies for Growing Australian Plants
  25. ISBN 0-7301-0007-3
  26. ^ CSIRO. 2000. About Australian Seagrasses Archived 2007-04-12 at the Wayback Machine
  27. ^ Robertson, A.I. and Alongi, D.M. 1995. Mangrove ecosystems in Australia: structure , function and status in D.P. Larr ed Our Sea, Our Future Major findings of the State of the Marine Environment Report for Australia Department of the Environment, Sport and Territories
    ISBN 0-642-17391-5
  28. ^
    ISBN 0-643-05972-5
  29. ^ Australian Biological Resources Study. Algae of Australia Archived 2006-07-17 at the Wayback Machine
  30. doi:10.1071/sb97006
    .
  31. doi:10.1071/sb04014
    .
  32. ^ McCarthy, P.M. 2006. Checklist of Australian Liverworts and Hornworts. Australian Biological Resources Study, Canberra. Version 6.
  33. doi:10.1071/sb00013
    .
  34. ^ McCarthy, P.M. 2006. Checklist of the Lichens of Australia and its Island Territories. Australian Biological Resources Study, Canberra. Version 6
  35. ^
    ISBN 978-0-901843-05-0
    .
  36. ISBN 978-07313-0004-4
    .
  37. ISBN 1-86436-816-0
  38. ISBN 0-9592892-0-8
    , p. 13.
  39. ^ O'Neill, G (1996). "Winning back the macadamia". Ecos. 88: 15–19.
  40. ^ Williams J. 2000, Managing the Bush: Recent research findings from the EA/LWRRDC National Remnant Vegetation R&D Program, National Research and Development Program on Rehabilitation, Management and Conservation of Remnant Vegetation, Research Report 4/00.
  41. ISBN 1-876977-20-5
  42. Department of the Environment and Heritage. EPBC Act List of Threatened Fauna Archived 2006-05-03 at the Wayback Machine
  43. ^ Department of the Environment and Heritage. 2002. Summary of Terrestrial Protected Areas in Australia by Type Archived 2006-09-13 at the Wayback Machine
  44. ^ Department of the Environment and Heritage. 2002. About the National Representative System of Marine Protected Areas (NRSMPA) Archived 2005-07-18 at the Wayback Machine
  45. ^ Department of the Environment and Heritage. National Biodiversity Hotspots, 2003, Archived 2006-08-20 at the Wayback Machine
  46. ^ Department of the Environment and Heritage IBRA Version 6.1 Archived September 8, 2006, at the Wayback Machine

General references

External links

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