Habitat loss, climate change, and invasive species continue to drive up the number of species threatened with extinction. However, data from the Threatened Species Index shows active protection of threatened species can stabilise trends.
The number of EPBC Act List of Threatened Species increased to 2,138 – a 52% increase since 2000. Forty one species were added to the list in 2024, down from the record 130 added in 2023 but still above the average rate of 25 additions per year. Additionally, 14 species were uplisted to a higher category of extinction risk. The buff-breasted buttonquail Turnix olivii was uplisted to Critically Endangered, but there is a greater than 50% chance the species is already Extinct. The presumed extinct Diel’s wattle Acacia prismifolia was rediscovered during roadside vegetation surveys in Western Australia.
The effects of the 2019-20 bushfires continue to be seen, with 51% of newly listed and uplisted species having been directly impacted by the fires. Even for species that escaped the worst of the blaze, such as the spiral sun orchid Thelymitra matthewsii, fire management activities – such as track maintenance, earthworks, and fuel reduction activities – resulted in population declines. Three new fish species were listed, all of which are endemic to Witjira-Dalhousie Springs, a chain of natural artesian springs on the edge of the Simpson Desert. All three species were listed as Critically Endangered, with their greatest threat being water extraction from the Great Artesian Basin for agriculture. Similarly, but 2000 km north of Dalhousie, the Pig-nosed Turtle Carettochelys insculpta was listed as Vulnerable, with its primary threat being water extraction for agriculture from the Daly and Alligator rivers.
The King Island Scrub Complex was added to the List of Threatened Ecological Communities, bringing the total number of listed communities to 107. King Island Scrub is home to four EPBC listed bird subspecies and was formerly home to other restricted subspecies that are now extinct. This community has a very restricted geographic distribution on King Island. The island was historically cleared for agriculture, and suffers ongoing losses due to clearing and unsuitable fire regimes.
The Sydney basin had the highest number of additions to the threatened species list (16), followed by the NSW North Coast (15) and South Eastern Queensland (13).
Only five species – a mere 0.2% of listed species – were downgraded to a lower threat category in 2024. The Southern Bluefin Tuna Thunnus maccoyii – formerly listed as Conservation Dependent – was removed from the EPBC list following population recovery. It joins the short list of only 11 species that have been removed from the EPBC list due to population increases, not counting the two species that were subsequently relisted.
While there is sufficient information to assess the risks to some taxa – namely terrestrial vertebrates – the EPBC list does not adequately represent invertebrates. There has been only one listed invertebrate extinction – the Lake Pedder Earthworm Hypolimnus pedderensis – but research indicates that over 9000 invertebrate extinctions have likely already occurred since colonisation.
Threatened Species Index
The Threatened Species Index (TSX) tracks changes in the abundance of threatened and near-threatened species in Australia. In 2024, alongside updates to the bird, mammal, and plant indices, Australia’s first Threatened Frog Index was launched.
Overall, the species listed as threatened under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) that are included in the TSX have experienced substantial long-term losses, with an average decline of 58% since 2000. The results from the 2024 TSX update revealed that between 2020 and 2021, the overall trend across all groups showed a slight increase (2%), driven by the stabilisation of declines and some recovery across species groups. However, more monitoring data is needed to determine whether this represents a lasting turnaround or a temporary pause in declines.
Approximately 20% of Australia’s frog species are threatened with extinction. Among those listed as threatened under the EPBC Act and included in the TSX, preliminary data suggests that abundance in 2021 was 71% lower on average than in 2000, with an average annual decline of 3%. Threatened frog populations affected by the amphibian chytrid fungus declined by 60% on average compared to 1997, while those not known to be impacted declined by 75% on average. The steeper decline in non-chytrid-impacted species may reflect the fact that the most severe chytrid-related losses occurred before 1997.
The trend for birds closely follows the overall index, with an average decline of 53% since 2000. Terrestrial birds experienced the largest declines (-59% on average). Mammal abundance in 2021 was 41% lower on average than in 2000, with critical weight range mammals facing the largest decline of 58% on average. The trend for threatened plants showed an average decline of 64% since 2000.
The latest TSX data reveals that species protection and management can be effective measures for slowing threatened species declines. For example, the abundance of threatened plants at actively managed sites remained stable at 21% below 2000 values, whereas those without protection declined by 73% on average since 2000.
Relative abundance of different categories of EPBC Act listed threatened species since 2000, as collated by the Threatened Species Index. The Index implements a 3-year lag, such that these trends go up to 2020
Threatening processes
The three most prevalent threats to species listed in 2024 were habitat loss and degradation, climate change, and invasive species and diseases. Ongoing habitat destruction for agriculture and aquaculture affected 32% of newly listed species. Other drivers of habitat loss were mining, energy production, forestry, and urban and commercial development. Climate change is a major threat to Australian biodiversity, due to increased temperatures, drought, extreme weather events, increased fire frequency and severity, and rising sea levels.
These threats were listed as the primary driver of decline for 64% of newly listed (25) and uplisted (10) species. Continued extraction of fossil fuels not only contributes to climate change, but also directly threatens biodiversity. The dusky sea snake Aipysurus fuscus (listed as Endangered in 2024) had already suffered significant population declines due to marine heatwaves and warming oceans driven by climate change.
Now, its remnant reef habitat in the Timor Sea is threatened by gas field development. Similarly, coal mining is the primary threats to the Hunter Valley Delma Delma vescolineata (first described in 2022 and listed in 2024 as Endangered) and the plant Ptilotus uncinellus (listed as Endangered in 2024).
In addition to the TSX, the Red List Index for Australian birds was updated in 2024 (reporting on the period 1990-2020) and showed a 3.3% increase in extinction risk. In the past, invasive predators and habitat destruction were the biggest threats to Australia’s birds, but that is being surpassed by climate change induced threats.
The Black Summer bushfires contributed half of the increase in extinction risk in the last decade. Few species show signs of recovery: only 12% of birds (25 of 199 eligible taxa) had a reduced threat status (1990-2020).
Threatened birds on Macquarie Island have experienced the greatest gains due to the removal of invasive species. Of the species added to the EPBC list in 2024, 20% (8) were migratory shorebirds. Conserving shorebird habitat is a complex international problem that requires protection of habitat along their 13,000km migration route from the Arctic Circle to Australia. Loss of stop-over habitat on the Yellow Sea has driven declines, but increasingly loss of habitat in Australia for coastal development is compounding the threat.
