Appendix D Terrestrial and Aquatic Biodiversity - Environment ...

SZ247: Bat survey from the Western Desert Resources Towns River project area, NT
The trapping effort was helpful for confirming the presence of both Scotorepens greyii and
Chalinolobus nigrogriseus. These two species produce echolocation calls with similar
characteristic frequency and pulse structure variation, and are difficult to distinguish reliably
from each other. Likewise, trapping confirmed the presence of other species that are
problematic to identify from their echolocation calls: S. flaviventris (calls are similar to S.
saccolaimus), and N. geoffroyi (calls are similar to N. arnhemensis and N. daedalus), however
the presence or absence of the other 'alternative' species could not be confirmed without their
capture.
4.4 Searches for roosts
Three traverses were made for tree roosts of Saccolaimus spp. in Eucalyptus tetrodonta Mid
Open Woodland (DT01) and in riparian communities such as Melaleuca nervosum Low Open
Woodland / Eucalyptus camaldulensis Low Open Woodland (DT02, DT03). A total of 10
trees were inspected with the pole camera, two of which were relatively deep vertical hollows
in the main trunk of the tree (Table 6). No bats of any species were observed.
Rocky outcrop, as observed on the various helicopter flights around the project area (e.g.
HEL01; Figure 2) was limited to a few areas, and none appeared to be of significant elevation
or structure to form caves or crevices suitable for cave roosting bats.
4.5 Identification from DNA barcoding
The purpose of DNA barcoding the tissue samples taken from field captures was to confirm
species identity, given that some diagnostic morphological characters are not always obvious
when in the field, there was some variation observed in the fur colour of small vespertilionid
bats, and there was the possibility of morphologically cryptic species in this region that has
seen relatively few bat surveys. Identification to family and genus was straightforward based
on external morphological characters (Churchill 2008), however species-level identity based
on both morphology and expectations derived from generalised distributions in field guides
such as Churchill (2008) was to be confirmed using DNA markers.
Most of the tissue biopsies from the captured bats amplified successfully for both
Cytochrome-b and Cytochrome Oxidase I mitochondrial DNA markers. A distance
phylogram created for each marker grouped samples of the same species into clades based
on the genetic distances between each sample (Figure 6). Unfortunately, very few DNA
sequences from Australian bats are available as context in GenBank (URL:
http://www.ncbi.nlm.nih.gov/ ), which limited the association of the test samples with reference
DNA sequences from reliably identified species. However, field identifications were still able
to be confirmed by the observing whether there was significant genetic distance within
putative species sets that would be indicative of more than one species. In the case of
Chaerephon jobensis, Chalinolobus nigrogriseus and Nyctophilus geoffroyi the observed
degree of genetic variation was indicative of one species only. In the case of small
vespertilionids (biopsy codes V1 – V9; S1), there were two distinct well supported clades
within putative Scotorepens greyii. One of the clades is likely to be S. greyii, and the other
may either represent genetic variation within the species, or a second species.
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