Appendix D Terrestrial and Aquatic Biodiversity - Environment ...

SZ247: Bat survey from the Western Desert Resources Towns River project area, NT
main report, as determined by EcOz Environmental. Nets were attended at all times for
between 3 – 5 hours after the end of civil twilight. In addition, a harp trap was left for two full
nights in thick riparian vegetation surrounding a small creek flowing from a rocky outcrop
(Corymbia polycarpa Mid Open Woodland; site H01; 1 – 2/2/2012).
Captured bats were given a field identification based on their appearance and by noting
distinguishing characters described by Churchill (2008). A wing biopsy was taken for genetic
analysis (see section 3.7 below), and the individuals were released within 2 hours at the
capture site. Only one individual was euthanised (using 0.1 mL Nembutal; under the South
Australian Museum's 'Licence to possess an S4 drug', licence number 2011-76256): the
single specimen of Saccolaimus captured at M03 on 3/2/2012.
3.6 Searches for roosts
Two types of bat roost were considered during the survey: caves and crevices in rocky
outcrops; hollows and beneath the bark of trees. The use of a helicopter to access water
bores across the MLA – Towns River project area during the survey period provided an
excellent opportunity to check the entire lease for rocky outcrop and make a determination of
whether those formations observed could provide underground habitat suitable for bats
(transect HEL01; Figure 2). The vegetation communities across the project area were also
observed from the helicopter in order to define patches that had the largest hollow-forming
tree species (typically Eucalyptus tretrodonta and E. miniata).
Three relatively brief (c. 1-hour long) searches were made in Eucalyptus woodland habitats
for roosts of S. saccolaimus using a novel method based on video observation. A small
video camera and white LED light source was attached to the end of a 10 m telescopic carbon
fishing rod and either lowered down into vertical hollows (1 – 2 m) or poked into horizontal
hollows. The video feed was recorded onto a small digital recorder for later examination. A
variety of hollows were targeted, particularly those large enough to contain bats of medium
size (i.e. Saccolaimus spp.) such as deep vertical hollows in the main trunk. Usage of this
type of hollow has been noted previously, for example a recent discovery of a colony in Cairns
(G. Ford pers. comm. 27/1/2012). While it has been used by other bat researchers in
Australia previously (e.g. Reardon 2000), the pole camera is not a standard piece of
equipment for surveying bats as part of environmental assessments in Australia, and it was
essentially being evaluated for its utility on the present survey.
3.7 Identification from DNA barcoding
The identity of captured bats was to be confirmed through DNA barcoding, given that the area
has not been surveyed well for bats previously, and to provide a more robust basis for species
name allocation compared to a simple morphological examination in the field. A tissue
biopsy was taken from the wing membrane of each capture using a sterile 4 mm dermal
punch, and stored in 50:50 saline:ethanol solution.
In the laboratory, the biopsies were first soaked for 24 hours in phosphate buffered saline
solution to remove the ethanol, and then extracted with a Gentra DNA purification kit. Two
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