A record number of species were added to the Threatened Species List. The abundance of Threatened Species continues to decline. Invasive species, habitat destruction and climate change remain the greatest threats.
Despite generally good wetland conditions, dry conditions in winter and spring may have contributed to waterbird breeding activity an order of magnitude lower than 2022.
Another mass mortality event of millions of fish occurred on the Darling River at Menindee, NSW, in part due to receding floodwater and resulting algal and bacterial blooms.
Hundreds of migrating seabirds washed up dead or dying on eastern beaches in November due to a marine heatwave. The sooty shearwater was listed as Vulnerable in 2023, with climate change impacts on food supply cited as the main reason for their decline, along with drowning as bycatch in fisheries. An emergency collection of 25 Critically Endangered red handfish occurred in December to save them from a catastrophic marine heatwave in Tasmanian waters.
The Victorian grassland earless dragon was rediscovered after 50 years but was ‘uplisted’ from Endangered to Critically Endangered. The primary threat to this species is Melbourne’s urban sprawl across the also critically endangered Victorian volcanic grasslands.
At least 40 new species were discovered. They were mostly invertebrates; it is estimated that only a third of Australia’s invertebrates have been named. Others were similar-looking species not previously understood to be distinct. Among the discoveries was a giant trapdoor spider from central Queensland, Euoplos dignitas, which is likely to be listed as Endangered due to land clearing in its Brigalow Belt habitat. Citizen science data helped describe two new species of frogs: the Otway smooth frog and the Western laughing tree frog.
Hundreds of species were assessed in 2023 in a push to make the EPBC lists as accurate as possible; a move precipitated by the catastrophic 2019-20 bushfires.
A record 130 species were added to the EPBC Act List of Threatened Species, bringing the total number of threatened species to 2,098 – a 47% increase since 2000. The previous highest number of additions was 62 species in 2009. Of the 130 newly listed species, nearly half (64) were directly impacted by the 2019- 20 bushfires. Of these, 58% were plants, 20% were freshwater crayfish and 10% were freshwater fish.
Another 33 species were uplisted to a higher threat category and no species were downlisted.
Three ecological communities were added to the EPBC Act List of Threatened Ecological Communities, bringing the total number to 106. The Empodisma peatlands of south-western Australia were listed as Endangered, having been assessed as under considerable threat from a drying climate, high- frequency fires and damage from feral pigs.
Frogs are the most threatened class of vertebrates worldwide, with 40% of species threatened globally and 20% of Australian species threatened with extinction. While disease and habitat loss drove previous declines, climate change now drives most of the deterioration in status. Six frog species were added to the threatened species list in 2023.
Threatened Species Index
The Threatened Species Index (TSX) estimates the changing abundance of threatened and near-threatened species in Australia, with data for birds, mammals and plants currently included. A major update for threatened birds in 2023 revealed continuous and compounding declines across Australia.
Among bird species listed as threatened under the Australian Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and included in the TSX, abundance in 2020 was 55% lower on average than the year 2000, with an average annual rate of decline of 2.8%. Terrestrial birds showed the greatest declines since 2000 (62%), followed by migratory shorebirds (47%) and marine birds (24%), since 2000.
The most significant declines across bird species included in the TSX were in South Australia (76%) and Queensland (67%). The ACT and New South Wales recorded a decline of 59%, Western Australia 51%, Victoria 51%, and Tasmania 33%. The trend for the Northern Territory showed a decline of 13% overall but with considerable uncertainty in the trend, driven strongly by data for migratory shorebird species.
Among species listed as threatened under the EPBC Act and included in the TSX, abundance in 2020 was 46% lower for mammals and 71% lower for plants.
The abundance of threatened mammals has stabilised in recent years, driven strongly by the stabilisation of many small mammal (<50g) populations and the recovery of some large mammals (>5000g).
The latest TSX data again revealed that species protection and management can be an effective measure for slowing threatened species declines. For example, the abundance of threatened plants at actively managed sites remained stable at 45% below 2000 values, whereas those without protection declined by 73% on average since 2000.
Threatening processes
The greatest threats to Australia’s Environment continue to be climate change, invasive species and habitat destruction. Climate change was the major driver of new listings, threatening 87% of newly listed and uplisted species. For the remaining 13% of species, extinction risk factors included cane toad poisoning, habitat loss due to clearing and mining, myrtle rust and water extraction.
Past high rates of habitat destruction for forestry and agriculture appear to be gradually declining. New developments to accommodate Australia’s rapidly growing population pose a particular threat to local ecosystems and species, especially along the East Coast.
There is no single solution for Australia’s many invasive species.
Cane toads are moving westward across northern WA at an estimated 40-60 km per year. Cane toad ingestion was listed as the primary threat to three newly listed reptile species: Mitchell’s water monitor, northern blue-tongued skink and Mertens’ water monitor.
Lord Howe Island (NSW) temporarily closed to visitors in March following detection of the invasive plant-killing myrtle rust fungus. It had formerly been detected and eradicated from the island in 2016. Myrtle rust is listed as a key threatening process and has pushed 15 species of rainforest trees towards extinction. A control plan was implemented and there were no further detections on the island in October 2023.
