Why the grey-headed flying-fox is listed as a threatened species

A threatened species is one that has been formally determined to be threatened with extinction in the near future.

We often think of a threatened species as rare, such as the Javan rhinoceros with fewer than 100 individuals left in the world.

However, there are many factors than can influence the risk of extinction of a species and thus its conservation status. These factors include:

  • the number of individuals remaining
  • overall increase or decrease in the population over time
  • breeding success rates
  • change in geographic distribution
  • known threats.

In the case of the grey-headed flying-fox, its conservation status is based not on the numbers of animals in existence, but on the rapid rate of decline in numbers over a relatively short period.

To use an analogy, imagine that the number of people in Australia suddenly dropped from 23 million in 2015 to just 13 million in 2025. There would still be millions of people in Australia, but the rate of decline would be cause for great concern. Prompt action would be required to halt any further decline.

Threatened species listing process

There are several lists of threatened species under state and Australian legislation, as well as an international list established under the International Union for Conservation of Nature (IUCN) Red List guidelines. Species at different levels of extinction risk are put in different categories, such as Critically Endangered, Endangered or Vulnerable. In some cases a species can be listed as threatened under the NSW Biodiversity Conservation (BC) Act 2016, the Commonwealth Environment Protection and Biodiversity Protection (EPBC) Act 1999, and the international Red List. The grey-headed flying-fox is listed as Vulnerable on all three lists.

When a species is nominated for listing as threatened, it is assessed against specific criteria by an expert scientific committee. Depending on the jurisdiction, the committee or the relevant Minister then makes a listing decision for that species. In NSW the committee is independent of government and they are responsible for determining which species, populations and ecological communities should to be listed under the BC Act. Determinations are made on the basis of the available scientific evidence only. Any consequences of that determination are a matter for the relevant Minister and government.

For more detailed descriptions of nomination and listing processes see the Australian government's process and the NSW government's process.

NSW conservation status

The grey-headed flying-fox was listed as Vulnerable by the NSW government through the Threatened Species Conservation Act in 2001. This listing was transferred to the Biodiversity Conservation Act 2016 when it came into force on 25 August 2017.

At the time of listing, the species was considered eligible for listing as Vulnerable as counts of flying-foxes over the previous decade suggested that the national population may have declined by up to 30 per cent. It was also estimated that the population would continue to decrease by at least 20 per cent in the next three generations given the continuation of the current rate of habitat loss and culling.

The main threat to grey-headed flying-foxes in NSW is clearing or modification of native vegetation. This threatening process removes appropriate sleeping and breeding sites and limits the availability of natural food resources, particularly winter-spring feeding habitat in north-eastern NSW. The urbanisation of the coastal plains of south-eastern Queensland and northern NSW has seen the removal of annually-reliable winter feeding sites, and this threatening process continues.

A range of other factors were also considered during the listing process.

National conservation status

The grey-headed flying-fox was listed as Vulnerable by the Australian government through the EPBC Act in 2001.

At the time of listing, the species was considered eligible for listing as Vulnerable as estimates of the species' abundance between surveys in 1989 (566,000) and 1998-2001 (400,000) indicated a rate of decline in the order of 30 per cent.

Species recovery and 'de-listing'

For a species to be found eligible to be removed from the threatened species list evidence must be provided to demonstrate that the species no longer meets any of the five criteria for listing and is therefore not considered threatened.

Evidence must also be provided to demonstrate that the removal of conservation management programs for the species as a result of it being removed from the list of threatened species would not result in the species becoming eligible for listing in the foreseeable future.

In the case of the grey-headed flying-fox, delisting would require demonstrating that the species population did not meet the criterion of population size reduction over a 10-year period. To understand whether the grey-headed flying-fox population is increasing, stable or decreasing a National Flying-fox Monitoring Program is underway to establish a reliable benchmark on the size of flying-fox populations in 2013 and monitor population trends in subsequent years.

The 2015 CSIRO report on the Status and trends of Australia's EPBC-listed flying-foxes estimated that the population of grey-headed flying-foxes has remained relatively stable, but potentially has declined slightly since 2005. Given that the known threats to the species continue to be threats and that new threats such as extreme heat events are emerging, the report suggests that the conservation status of the grey-headed flying-fox should at the very least remain as Vulnerable.

Page last updated: 24 April 2018