Threatened Species and threatened ecological communities
Advice to the Minister for the Environment and Heritage from the Threatened Species Scientific Committee (TSSC) on Amendments to the list of Threatened Species under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)
Taphozous troughtoni (Troughton's Sheathtail-bat)
This species is endemic to Australia. Its distribution is poorly understood, but the species is known to occur in the Mt Isa region, ranging well into central and south-east Queensland.
Troughton's Sheathtail-bat has been nominated as critically endangered and was classified as critically endangered in the 1999 Bat Action Plan. At that time, there was little known about the species and, in fact, its specific status was in doubt, the possibility existing that it was simply a larger form of the very similar Common Sheathtail-bat Taphozous georgianus. Recent research to clarify the taxonomic status of this species suggests that it is a valid taxon, however, that a listing of critically endangered is not appropriate.
TSSC judges the species to be ineligible for listing as critically endangered, or any other level of threat, under the EPBC Act. The justification against the criteria is as follows:
At the time the Bat Action Plan was completed, the species was known from only a handful of specimens which had been collected at three locations in the Mt Isa region. In March 2000, field work was conducted in the Mount Isa region to resolve the taxonomic uncertainty surrounding Troughton's Sheathtail-bat. A number of specimens were located and, using molecular techniques, it has now been shown that both Troughton's Sheathtail-bat and the Common Sheathtail-bat are sympatric in the Mt Isa region and throughout much of south-eastern and central Queensland. The expert conducting this work considers that Troughton's Sheathtail-bat is a distinct species and is far more common than thought at the time the Bat Action Plan was prepared. This work has indicated the area of occurrence to be at least 7,000 km2. Additional genetic studies and survey work is planned for later in 2001 to refine the species taxonomic and distributional boundaries.
From the limited data available it is impossible to establish the size of the current population, whether it has declined and, if so, by how much. At this time, there is no evidence to indicate that Troughton's Sheathtail-bat has undergone a severe reduction in numbers, and threatening processes likely to affect the species have not been identified.
Therefore, the species is not eligible for listing under this criterion.
The area of occurrence for Troughton's Sheathtail-bat is estimated to be at least 7,000 km2. Whilst this is small in comparison to that of most other bat species in Australia, it cannot be argued that its geographic distribution is precarious at this stage.
Therefore, the species is not eligible for listing under this criterion.
It is not possible to estimate the size of the population of Troughton's Sheathtail-bat at this time, although this may be possible after more thorough survey work is done later in 2001. However, no threats to the species have been identified and there is no evidence to suggest that the population will decline at a high rate, or that its distribution is precarious for its survival.
Therefore, the species is not eligible for listing under this criterion.
The data presented under Criterion 3 do not support listing under Criterion 4.
Therefore, the species is not eligible for listing under this criterion.
There is no quantitative evidence available against this criterion. However, the species now appears to be far more common than originally thought, there seems to be suitable natural roosting habitat throughout at least the Mt Isa area, and there is little likelihood of population decline or extinction in the near future.
Therefore, the species is not eligible for listing under this criterion.
Troughton's Sheathtail-bat has a wider distribution than originally thought. Confirmation of its conservation status requires refinement of both its genetic and distributional boundaries. Whilst listing as critically endangered is not appropriate at this stage, completion of additional survey work is important and should be encouraged to confirm that the species is secure. The species conservation status should be reassessed at that time or, at the latest, within three years.
TSSC recommends that the species Taphozous troughtoni (Troughton's Sheathtail-bat) is not eligible for inclusion in the list referred to in section 178 of the EPBC Act.
TSSC recommends that the conservation status of this species be reviewed by the Threatened Species Scientific Committee in 2004 or sooner following clarification of genetic and distributional boundaries.