What is biodiversity?

Biodiversity in Australia refers to the variety of life across the country, from microorganisms to plant and animal species, ecological communities, and the genetic variation within species. Australia is recognised as one of 17 megadiverse countries identified by the United Nations Environment Programme, hosting an estimated 7 to 10 per cent of all species on Earth on just 5 per cent of the planet's land area.

The country's biodiversity is dominated by endemic species, organisms found nowhere else in the world. About 85 per cent of Australia's flowering plants, 84 per cent of mammals, 45 per cent of birds, and 89 per cent of reptiles are endemic. The south-west of Western Australia is one of the world's 36 recognised biodiversity hotspots, with about 8,000 plant species, of which more than half are found only in the region. The Wet Tropics of Queensland and the eastern temperate forests are also centres of endemism.

Australia also has one of the highest extinction rates in the world. Since European settlement in 1788, more than 100 species are known to have become extinct, including 34 mammal species (about 10 per cent of the country's mammal fauna), more than any other country in the same period. Recent extinctions include the Bramble Cay melomys, declared extinct in 2019 (the first mammal extinction attributed primarily to climate change), and the Christmas Island pipistrelle, last recorded in 2009. About 1,900 species are listed as threatened under the EPBC Act.

Conservation responses include the National Reserve System (about 22 per cent of land protected through national parks, conservation reserves, and Indigenous Protected Areas), recovery plans for individual species such as the koala, the orange-bellied parrot, and the Tasmanian devil, and threat-abatement plans for invasive species like the cane toad, the European red fox, the feral cat, and the rabbit. Climate change, land clearing, invasive species, and altered fire regimes remain the main drivers of biodiversity loss.