Biodiversity Theme Report

Australia State of the Environment Report 2001 (Theme Report)
Prepared by: Dr Jann Williams, RMIT University, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06749 3

The Meaning, Significance and Implications of Biodiversity (continued)

Key features of Australia's biodiversity

  • Vegetation types
  • Marine habitats
  • Classifying vegetation or habitat types
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    Vegetation types

    The terrestrial ecosystems found in Australia are very varied owing to the range of climates - including subalpine, cool temperate, arid and tropical biomes. This diversity leads to a range of vegetation types whose distribution at a broad scale is limited mainly by rainfall. These include the spinifex-dominated arid interior, semi-arid shrublands, tropical and temperate grasslands, rainforests and woodlands (including savannas), eucalypt-dominated forests and shrublands, chenopod shrublands, heathlands, alpine and subalpine vegetation (Groves 1994; Flora of Australia 1999). The only available Australia-wide map of Australia's natural vegetation (Figure 3) was compiled by JA Carnahan (Commonwealth of Australia 1990). During 2001, a new continental-scale vegetation map is to be produced by the National Land and Water Resources Audit (NLWRA) (see http://www.nlwra.gov.au ). This is part of a major initiative, the National Vegetation Information System, which is a collaborative project between the state, territory and Commonwealth governments.

    Figure 3: Major vegetation types in Australia in 1988.
    The National Vegetation Information System is developing an interactive database that will allow mapping of native vegetation at several scales.

     Major vegetation types in Australia in 1988

    Source: Commonwealth of Australia (1990). Compiled by Environmental Resources Information Network

    Australian terrestrial vegetation contains very few deciduous species, relatively few conifers and no cactuses or other large succulents in the arid zone. In particular, the appearance of the unique Australian landscape is largely as a result of the predominance of species-rich genera such as Eucalyptus and Acacia.

    Mangrove forests and saltmarshes occur in intertidal areas and are thus influenced by the characteristics of both the land and the sea. Intertidal mudflats are another significant, yet often forgotten, habitat.

    Aquatic vegetation types, especially in the marine environment, are much less diverse than their terrestrial counterparts. For example, vegetation communities in marine areas are largely dominated by seagrasses and macroalgae (Zann 1995). A broader range of vegetation types are associated with the lakes, rivers, wetlands and areas dependent on ground water that help make up the freshwater systems of Australia (Boulton & Brock 1999).

    Table 1: Comparative socioeconomic data for the 17 megadiverse nations
    Updated from Common and Norton (1992). All figures are from 1998 except life expectancy (1997), protected areas (1996) and the income figures for the DRC (Congo) and Malaysia that are based on regression. Figures for the land area of China, Brazil and Australia have increased since 1989.
    Country Population
    (millions)
    Area
    (thousands km 2 )
    Population density
    (persons km 2)
    Life expectancy
    (y)
    Income
    (per capita US$)
    Agriculture
    (% of output)
    Nationally protected areas
    (% land area)
    Adult literacy rate (%)
    Australia   7 741 2 78.2 20 130 3 7.3 99.0
    Brazil 166 8 547 20 66.8 6 160 8 4.2 84.0
    China 1 239 9 597 133 69.8 3 220 18 6.4 82.9
    Colombia 41 1 139 39 70.4 7 500 13 9.0 90.9
    DRC 48 2 345 21 50.8 750 58 4.5 79.5
    Ecuador 12 284 44 69.5 4 630 12 43.1 90.7
    India 980 3 288 330 62.6 1 700 25 4.8 55.0
    Indonesia 204 1 905 112 65.1 2 790 16 10.6 85.5
    Madagascar 15 587 25 57.5 900 31 1.9 65.0
    Malaysia 22 330 68 72.0 6 990 12 4.5 86.5
    Mexico 96 1 958 50 72.2 8 190 5 3.7 90.1
    Papua New Guinea 5 463 10 58.0 2 700 NA 0.0 NA
    Peru 25 1 285 19 68.3 NA 7 2.7 88.7
    Philippines 75 300 252 68.5 3 540 NA 4.9 94.5
    South Africa 41 1 221 34 65.0 6 990 NA 5.4 84.0
    USA 270 9 363 29 76.0 29 340 NA 13.4 NA
    Venezuela 23 912 26 73.0 8 190 NA 36.3 92.5

    Source: World Bank (1999a, 1999b).

    The photographs below illustrate an indicative range of diversity of vegetation types. Some of these vegetation types such as tropical rainforests and alpine vegetation are restricted in occurrence. This contrasts with tropical savannas (dominated by eucalypt species) and spinifex-dominated grasslands which cover large areas of tropical and arid Australia, respectively. Another widespread community is the Mulga (Acacia aneura)-dominated shrublands. Together with hummock grasslands wooded with Mulga, these communities are estimated to occupy 1.5 million square kilometres or about 20% of the Australian continent (Hodgkinson 2001). Although most of the continent is dominated by semi-arid and arid ecosystems, ecosystem diversity is greatest in the higher rainfall regions on the eastern and southern edges of the continent.

    Cushion plant community Tasmania

    Cushion plant community Tasmania.

    Source: JJ Bruhl, University of New England

    complex mesophyll vineforest south of Cape Tribulation, Queensland

    Complex mesophyll vineforest south of Cape Tribulation, Qld.

    Source: VJ Neldner, Environment Protection Agency, Queensland

    Seagrass bed, Posidonia australis and Amphibolus antartica, near Rockingham, Western Australia

    Seagrass bed, Posidonia australis and Amphibolus antartica, near Rockingham, WA.

    Source: M Waycott, James Cook University

    Shrubby eucalypt woodland remnant on sandstone in the Glenorie area of the Hills District, north-western Sydney

    Shrubby eucalypt woodland remnant on sandstone in the Glenorie area of the Hills District, north-western Sydney.This woodland has a very diverse shrub layer including Boronia, Dillwynia, heath species and the rare and restricted Acacia gordonii

    Source: JJ Bruhl, University of New England

    Spinifex (Triodia spp.)-dominated grassland burnt most recently in 1991, north of Uluru-Kata Tjuta National Park, Northern Territory

    Spinifex (Triodia spp.)-dominated grassland burnt most recently in 1991, north of Uluru-Kata Tjuta National Park, NT.

    Source: JE Williams

    Dropseed (Sporobolus virginicu)-dominated grassland with termite mounds near Kowanyama, Queensland

    Dropseed (Sporobolus virginicu)-dominated grassland with termite mounds near Kowanyama, Qld.

    Source: VJ Neldner, Environment Protection Agency, Queensland

    Mulga (Acacia aneura)-dominated community in foreground with scattered individuals of the endangered Undoolyana Wattle (Acacia undoolyana) which can be identified by its bright green foliage

    Mulga (Acacia aneura)-dominated community in foreground with scattered individuals of the endangered Undoolyana Wattle (Acacia undoolyana) which can be identified by its bright green foliage.
    Spinifex (Triodia brizoides)-dominated hillside in the background on a different substrate. Undoolyana Station east of Alice Springs, NT

    Source: JE Williams

    Marine habitats

    Australia has one of the world's longest national coastlines and one of the largest marine jurisdictions, about twice the size of the Australian mainland ranging from the sub-Antarctic to the tropics. These measurements refer only to surface area - marine organisms live in all available habitats extending throughout the water column to the floor of deep ocean trenches. Some of these trenches reach 11 000 m in depth but even in these extreme habitats, marine invertebrates still occur. In addition to well-known habitats such as shorelines, estuaries, rocky shores and rock pools, coral reefs and seagrass beds, marine invertebrates can be found in other habitats such as the interstitial spaces between grains of sand, around hydrothermal vents, on floating debris (e.g. algal mats and driftwood attached to other animals), the peaks and slopes of seamounts and swimming or floating in the water itself.

    Classifying vegetation or habitat types

    Indigenous people have developed classifications for vegetation or habitat types that can bear marked similarities to the broad associations defined by western science (Table 2). While western science is based on evolutionary theory and Linnaean taxonomy, all aspects of Indigenous life is governed by the genesis of life and classification based on their religious and social laws (Baker & Mutitjulu Community 1992).

    Table 2: Indigenous words for arid zone systems and taxa
    Habitat type Anangu name
    Rocky range and outcrops puli
    Mulga shrublands puti
    Riverbed and riverbanks karu
    Sand plain pila
    Dunefields tali
    Saltlakes or claypans Pantu or tjintjira