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
- biodiversity, both through plants themselves and through the habitat that vegetation provides for other species
- regulating the climate, from the continental scale down to the micro scale
- ecosystem processes, such as producing energy through photosynthesis
- 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 through protection from water and wind erosion
- producing food, fibre, medicines and shelter.
Australia’s vegetation includes both native and introduced plant species. Our native vegetation is globally unique: 85% of Australian plant species are endemic (found nowhere else on Earth). The rich biodiversity of our vegetation (see Chapter 8: Biodiversity) is attributable to the continent’s geological and environmental history, and to the diversity of Australia’s climate and physical environment.
The most extensive types of Australian native vegetation are grasslands, woodlands dominated by eucalypts, and shrublands dominated by acacias. Non-native vegetation includes a diverse array of annual, perennial and horticultural crops from which we derive almost all our food, and plantation forests from which we source most of our wood. It also includes many weed species that have adverse impacts on environmental values.
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% has been completely converted to other land uses, and a further 62% 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 reported in this chapter.