Threats and key threatening processes

Identifying and mitigating threats is essential for recovery of threatened species and the restoration of species and their habitats. Most Australian species face multiple threats; on average, each threatened species faces around 4 different threats (Kearney et al. 2018a) (Figure 24). These threats may interact and be cumulative, such that the impacts are increased in an additive manner (see Interactions between pressures and cumulative impacts).

Invasive species, ecosystem modifications and agricultural activity are the threats identified in listing criteria of the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) as affecting the largest numbers of Australian threatened species (Figure 25) (Kearney et al 2018a).

The consequences of many threats are manifested through similar mechanisms. For example, habitat loss and degradation is the primary mechanism through which species are affected by various threats, including logging, mining, urbanisation, transportation, energy production and agricultural activity. As a result, habitat loss and degradation is the most dominant mechanism by which species are threatened in Australia, with nearly 70% of Australian threatened taxa impacted (Ward et al. 2021).

Figure 24 Number of threats listed as impacting EPBC Act–listed threatened species
Figure 25 Prevalence of threats to Australian threatened taxa

EPBC Act = Environment Protection and Biodiversity Conservation Act 1999


  1. n = 1,533
  2. Each graph is scaled according to the number of taxa listed under the Environment Protection and Biodiversity Conservation Act 1999 as being affected by each threat category (e.g. Urban development). Each chart segment represents a subclass threat (e.g. Housing). The threat category ‘Geological events’ is not shown here because it impacts <20 species, and subclass threats that impact <5 taxa (e.g. Renewable energy) are not shown because they were too small to be displayed effectively.
  3. ‘Agriculture (other)’ includes land clearing, habitat fragmentation and/or habitat degradation.

Source: Reproduced with permission from Kearney et al. (2018b)

Key threatening processes

A pressure can be identified and listed under the EPBC Act as a ‘key threatening process’ if it threatens the survival, abundance or evolutionary development of a native species or ecological community.

Currently, 21 key threatening processes are listed under EPBC Act:

  • 13 relate to pressures from invasive species
    • Aggressive exclusion of birds from potential woodland and forest habitat by over-abundant noisy miners (Manorina melanocephala)
    • Competition and land degradation by rabbits
    • Competition and land degradation by unmanaged goats
    • Invasion of northern Australia by Gamba grass (Andropogon gayanus) and other introduced grasses
    • Loss and degradation of native plant and animal habitat by invasion of escaped garden plants, including aquatic plants
    • Loss of biodiversity and ecosystem integrity following invasion by the yellow crazy ant (Anoplolepis gracilipes) on Christmas Island, Indian Ocean
    • Novel biota and their impact on biodiversity
    • Predation by European red fox
    • Predation by exotic rats on Australian offshore islands of less than 100,000 ha
    • Predation by feral cats
    • Predation, habitat degradation, competition and disease transmission by feral pigs
    • The biological effects, including lethal toxic ingestion, caused by cane toads (Bufo marinus)
    • The reduction in the biodiversity of Australian native fauna and flora due to the red fire ant (Solenopsis invicta)
  • 3 relate to pressures from pathogens or disease
    • Dieback caused by the root-rot fungus (Phytophthora cinnamomi)
    • Infection of amphibians with chytrid fungus resulting in chytridiomycosis
    • Psittacine circoviral (beak and feather) disease affecting endangered psittacine species
  • 4 relate to population pressures
    • Incidental catch (bycatch) of sea turtles during coastal otter-trawling operations (which drag a large net along the ocean floor) within Australian waters north of 28 degrees South
    • Incidental catch (or bycatch) of seabirds during oceanic longline fishing operations
    • Injury and fatality to vertebrate marine life caused by ingestion of, or entanglement in, harmful marine debris
    • Land clearance
  • 1 relates to climate change
    • Loss of climatic habitat caused by anthropogenic emissions of greenhouse gases.

No new key threatening processes have been listed since 2014, although a potential key threatening process is currently under review – fire regimes that cause biodiversity decline.