Like the soil that supports it, vegetation is fundamental to ecosystem processes and human survival. Vegetation is vital for:
- producing oxygen for animal and human life
- maintaining air quality by trapping particulates such as dust and pollutants
- maintaining biodiversity, through both plants themselves and the habitat that vegetation provides for other species
- regulating the climate, from the continental scale down to the microscale
- maintaining ecosystem processes—for example, capturing energy through photosynthesis (which supports food chains) and sequestering atmospheric carbon (which mitigates greenhouse gas emissions)
- maintaining hydrological processes involving surface water and groundwater, such as maintaining the porosity of soils and their capacity to retain water
- maintaining soil integrity and stability, including protecting the soil from water and wind erosion
- producing food, fibre, medicines and shelter
- providing vital cultural connection for Indigenous people, triggering seasonal cues for land management activities and harvesting of natural resources.
Australia has a huge and varied flora. More than 85 per cent of it is found nowhere else on Earth, which means that the majority of the natural vegetation that we see is made up of species that evolved in Australia to cope with Australian conditions. The main vegetation types are, in order of area of extent (according to amalgamated major vegetation groups; DoEE 2016), shrublands and grasslands, eucalypt forests and woodlands, open woodlands, other forests and woodlands, and rainforests.
We have also introduced an enormous number of species for our own purposes, particularly for agriculture and recreational gardening. Incredibly, there are now more introduced plant species (more than 41,000) in Australia than there are native species (around 20,000; Department of Agriculture and Food, Western Australia, unpublished data, 2015). The introduced species include agricultural, horticultural and forestry crops, as well as invasive species that pose huge problems for some commercial sectors and the environment.
Australia’s native vegetation has been modified to varying degrees by different land uses and management practices throughout the country’s human history. Since European settlement, some 13 per cent of native vegetation has been completely converted to other land uses, and a further 62 per cent is subject to varying degrees of disturbance. The cumulative impacts of land uses and management practices on the environmental values of Australia’s soils and native vegetation are a central concern for the assessments in this report.