Understanding of the state and trends of the vast majority of individual species in Australia is limited. The lack of effective monitoring data for understanding state and trends, even for threatened species, is highlighted by every jurisdiction and all previous state of the environment reports. Information about the extent of vegetation communities is good; however, most jurisdictions note that knowledge about vegetation condition is limited. Significant reports on the state of mammals (The action plan for Australian mammals) and birds (State of Australian birds) have improved understanding of these animal groups since 2011.

At the end of 2015, 74 ecological communities were listed as threatened under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act); 31 are critically endangered. There have been 30 new listings since 2011. Threatened ecological communities are concentrated in south eastern Australia. The overall number of threatened species listed under the EPBC Act has increased by 44, to 1808 species.

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 worsening.

Mammal declines in northern Australia have continued. In southern and eastern Australia, the number of species of conservation concern has increased. Bird groups 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 abundance of eastern Australian inland waterbirds and for 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.

The jurisdictions generally report the condition of aquatic ecosystems and species as poor to moderate, although the availability of information is also often described as poor or limited.