Overview of state and trends of biodiversity

2016

What has changed since 2011?

  • The list of nationally threatened species and ecological communities has increased, with the addition of 30 new ecological communities, and 44 animal and 5 plant species.
  • Two species have been listed as likely extinct: the Bramble Cay melomys (Melomys rubicola), and the Christmas Island forest skink (Emoia nativitatis). These species have not been formally reassessed under the EPBC Act.
  • Land-clearing rates stabilised in all states and territories, except Queensland, where clearing increased.

State and trends

Understanding of the state of biodiversity in Australia is improving for a small number of taxa, although our knowledge is inadequate because limited information is available for the vast majority of taxa, and few long-term monitoring programs are in place. The lack of data is pronounced for plants, amphibians and reptiles, and even more so for taxa such as freshwater fish, invertebrates and fungi.

Threatened species and communities

Based on the information available about vegetation extent and condition, and the small number of species for which there is some understanding of trends in distribution and abundance, the status of biodiversity in Australia is generally considered poor and deteriorating.

Grazing in the extensive land-use zone of Australia is considered a major threat to biodiversity. Along with other management changes, it is considered a key pressure on northern Australian mammal populations.

Mammal declines in northern Australia have continued. In southern and eastern Australia, the number of mammal species of conservation concern has increased.

Birds show variable trends, but some groups, such as woodland-dependent species in the mallee and carnivore species in the arid zone, are in significant decline. Trend analyses for eastern Australian inland waterbirds and some migratory shorebirds indicate that populations are currently well below long-term averages.

Very limited information is available to assess the state and trends of reptiles, amphibians and invertebrates, except for a few high-profile species.

As at December 2015, the numbers of threatened species and threatened ecological communities listed under the EPBC Act stood as follows:

  • 74 ecological communities, of which 31 were listed as critically endangered, 41 as endangered and 2 as vulnerable; 27 of these are new listings since 2011. EPBC Act–listed ecological communities are concentrated in south-eastern Australia
  • 480 animal species, including 55 listed as extinct or extinct in the wild, an increase of 44 species since 2011. The number of nationally listed threatened animal species has increased for all taxa except amphibians
  • 1294 plant species, including 37 species listed as extinct. Since 2011, there has been an overall increase of 5 species listed. Movements within the list include an increase of 31 species in the critically endangered category, and a decrease in the number of species in the endangered and vulnerable categories because of delistings and uplistings to endangered and critically endangered. The highest number of listed plant species occurs in the south-west of Western Australia and in south-eastern Australia.

In northern Australia, ongoing mammal declines (species extinction, regional extinctions and reduction in local population numbers) have continued to be evident, particularly in the Top End of the Northern Territory and the Kimberley region of Western Australia. Australia has a very poor record in recent extinctions of mammal species.

Terrestrial habitats

The condition of terrestrial habitats in Australia has been influenced by historical land clearing, degradation and fragmentation. Although nearly 90 per cent of Australia’s native vegetation remains in some form, 24 broad vegetation communities (32 per cent of the 75 evaluated) have lost at least 20 per cent of their original extent, and 7 communities (9 per cent) have lost more than 40 per cent of their original extent.

Trends in vegetation condition and extent are variable across the jurisdictions, with most jurisdictions reporting declines in condition and extent. Although clearing rates have mostly stabilised, habitat fragmentation continues, and there are now fewer large patches of contiguous vegetation than in 2011 (see ‘Land-use change, and habitat fragmentation and degradation threaten ecosystems and resilience’).

Small patches are more likely to be cleared and are susceptible to deterioration of condition because of a range of pressures, including weed invasion, fire and disturbance from surrounding land uses. Increased fragmentation also increases the impacts of invasive species and bushfires, and decreases ecosystem functions such as pollination and seed dispersal.

Jackson WJ, Argent RM, Bax NJ, Bui E, Clark GF, Coleman S, Cresswell ID, Emmerson KM, Evans K, Hibberd MF, Johnston EL, Keywood MD, Klekociuk A, Mackay R, Metcalfe D, Murphy H, Rankin A, Smith DC, Wienecke B (2016). Overview: Overview of state and trends of biodiversity. In: Australia state of the environment 2016, Australian Government Department of the Environment and Energy, Canberra, https://soe.environment.gov.au/theme/overview/biodiversity/topic/overview-state-and-trends-biodiversity, DOI 10.4226/94/58b65510c633b