Download Targeted species survey guidelines - brush

Targeted species survey guidelines
Vulnerable (Nature Conservation Act 1992) |
Ecological Sciences, Queensland Herbarium
Identification
Photo by P.A. Woolley & D. Walsh
Brush-tailed mulgara
Dasycercus blythi
A stocky, rat-sized carnivorous marsupial with a broad
head, pointed muzzle and rounded ears. The fur is light
sandy-brown above and greyish-white on the belly. The
thick, tapered tail is approximately 60 % of the head-body length, with reddish hair at the base and black hair
on the final two-thirds (Woolley 2005; Masters 2012). It is distinguished from the closely related crest-tailed
mulgara D. cristicauda by its generally smaller size and its smooth tail, and lacking the fin-like crest of black
hairs on the tail’s dorsal surface of D. cristicauda (Woolley 2005). Female D. blythi have six nipples, versus
eight for D. cristicauda (Woolley 2005). Males are bigger than females (Masters et al. 2003). Also similar to the
kowari Dasyuroides byrnei, which has a narrow rather than thick tail-base and four toes on hindfoot versus five
in the mulgara (Menkorst and Knight 2011).
Distribution
Dasycercus blythi is found from the Simpson Desert in far
south-western Queensland across the arid interior through the
Tanami and Great Sandy Deserts of southern and central
Northern Territory and central Western Australia (Woolley
2008). There is some uncertainty over its historical
distribution, with taxonomy and nomenclature only finally
resolved in 2005 (Woolley 2005), but it has certainly declined
from its southern extent (Masters 2008). Despite substantial
surveys, there have been no records of the species in South
Australia since 1966 (Masters 2012).
Habitat
Favoured habitat of D. blythi includes spinifex Triodia spp. grasslands on sand plains and the swales between
low dunes. The species is generally considered to be associated with spinifex on flat to gently sloping
topographic positions, with or without an open mulga Acacia aneura woodland overstorey (Woolley 2008;
Masters 2012; Pavey et al. 2011). Also recently recorded from gibber plains, although burrows were restricted
to sandy patches or mounds (Pavey et al. 2011).
Targeted species survey guidelines: Dasycercus blythi
The species has been recorded in the absence of spinifex cover; in burnt or regenerating landscapes (Masters
et al. 2003; Letnic and Dickman 2005; Körtner et al. 2007), but possibly only as short-term residents (P.
Masters pers. comm. 2012). Mature spinifex hummocks appear to be a particularly important resource in
protecting mulgaras from introduced predators (e.g. Gibson and Cole 1992; Körtner et al. 2007).
More rarely, it has been found in habitats dominated by tussock grasses and forbs (sand plain and gibber
sites) (Pavey et al. 2011). The species was formerly found in chenopod shrublands, but are not currently
known from this habitat (Masters 2012).
Seasonal and timing considerations
In general, searches for signs and other inferential evidence, as well as hair trapping can be undertaken at any
time of the year. Tracks are best surveyed in the early morning when shadows are long.
To maximise detection success, trapping surveys should be undertaken during fine weather conditions, and
avoid the hotter months and inclement weather (i.e. rainfall periods). Populations do appear to decline
seasonally in winter and increase in spring after an influx of young animals (Pavey et al. 2011; Masters and
Dickman 2012). A second peak seasonal activity occurs in autumn when the young have matured and the
males are looking for mates, so surveys are best planned for these October to November and March to April
periods (Atlas of Living Australia 2013; P. Masters pers. comm. 2012). Opinions vary as to whether the
species undergoes climate-driven population increases (“boom” and “bust”) with several studies indicating
responses in the year following above-average rainfall (Gibson and Cole 1992; Dickman et al. 2001) whilst
others, including the longest study, have found no population increases after ‘good’ seasons (Masters 2012;
Greenville et al. 2012).
Recommended survey approach
The following survey techniques should be prioritised in order as per the headings below:
Box or Elliott trapping
Type ‘A’ Elliott trapping surveys are the most commonly employed technique for detecting D. blythi (e.g.
Masters et al. 2003, Körtner et al. 2007; Pavey et al. 2011). However, despite using a combination of both
Elliotts and pits in the Simpson Desert, Dickman and colleagues (2001) found pitfall traps to be far more
successful in catching dasyurids including D. blythi. Home ranges are large (25.5 ha for males and 10.8 ha for
females, Körtner et al. 2007) so trap spacing should be wider than is typically recommended. Bait traps using
universal bait (peanut butter and rolled oats).
Pitfall trapping
Mulgara require deeper and narrower pits to stop the animals from escaping, so we recommend using 600 mm
deep, 160 mm diameter PVC pipes with flywire caps rather than buckets. Pitfall arrays should target suitable
habitat (sandplains and swales), but can extend into more marginal habitat (sandridges, gibber plains,
shrublands).
Searching for signs (scats, tracks, burrows)
Daytime searches should target signs including burrows and pop-holes, particularly those with freshly
excavated earth. Burrow systems can have multiple entrances and tend to be within 2.5 m of the raised sandy
base of spinifex hummocks (Woolley 1990). Burrow entrances are 4-5 cm wide with a rounded base and can
be hidden under dense spinifex, amongst roots of shrubs such as Grevillea or Eremophila spp., or be in the
open (Körtner et al. 2007; Dickman et al. 2011; Masters 2012; Moseby i. 2012). Mulgara scats (20-30 mm
Page 2 of 5
Targeted species survey guidelines: Dasycercus blythi
long, 4-6 mm wide) are twisted, strong-smelling and are often deposited near burrows as territorial markers
(Triggs 2004; Pavey et al. 2009; Moseby et al. 2012). Mulgara tracks are best identified from their size (foot
size > 30 mm) and gait (hind feet placed together in front of front feet when moving) (see Moseby et al. 2012).
Signs of D. blythi cannot be separated from those of D. cristicauda, but can be used to target further Elliott,
pitfall or camera trapping efforts.
Hair and camera trapping
Hair sampling may be an option as both species of mulgara are apparently distinguishable from hair samples
(DSEWPaC 2011). While there is no information on efficacy of hair tubes in general (or different types of hair
tubes) for this species, hair funnels (Faunatech Pty Ltd) appear to be more successful than other designs for
some species of dasyurid (Mills et al. 2002; Nelson 2006).
Camera trapping may be a good alternative to live trapping as pictures showing the tail morphology can
differentiate between both mulgara species and the similarly-sized kowari (DSEWPaC 2011). Cameras can be
deployed for much longer periods, have fewer ethical issues than live trapping and can be very effective at
detecting animals at low densities (Vine et al. 2009). White-flash camera traps set for a minimum of 14 days,
with no time delay and an infinite number of photos per event, will be most likely to capture enough detail for a
positive identification (see Meek et al. 2012).
Cameras can be deployed on transects with bait attractants (e.g. in a metal cage wired to a star picket 2-3 m
away from the camera). Another good option is to place unbaited camera traps around burrow systems with
active burrows.
Survey effort guide
Detection rates for D. blythi have varied with different studies. For example, 8.9 captures per 100 Elliott-trap
nights at Uluru and the Tanami Desert (Masters and Dickman 2012), and 0.91 captures per 100 pit-trap nights
in the eastern Simpson Desert (Letnic and Dickman 2005), 0.27 captures per 100 trap nights (Elliotts and pits)
in the western Simpson Desert (Pavey et al. 2011). In Queensland, pitfall trapping at 12 sites at Ethabuka
Station in the Simpson Desert over a period of 22 years has yielded 438 captures of D. blythi from nearly
400,000 trap nights (0.11 captures per 100 pit-trap nights) (Greenville et al. 2012). The recommended level of
effort below may provide a reasonable opportunity to detect D. blythi if present in suitable habitat in the project
area.
Minimum effort per 20 ha of suitable habitat
Survey technique
Elliott trapping
Pitfall trapping
Searching for signs
Minimum Effort
3 trapping grids for 4 nights, each in 2 different survey periods (= 1200 trap nights).
Each grid: 2 rows of 25 Type ‘A’ Elliott’s each spaced at 25 m, rows spaced 50 m
apart.
2 arrays of 10 pits with 100 m drift fence for 4 nights, each in 2 different survey
periods (= 160 trap nights).
4 hours per survey day. Search 2 m either side of 100 m transects.
3 trapping grids for 14 nights, each in 2 different survey periods (= 1008 camera trap
nights). Each grid: 2 rows of 6 baited cameras each spaced 100 m apart, rows 50 m
Camera trapping
apart.
e.g. 150 Elliott traps and 20 pitfall traps for 4 nights, 36 camera traps for 14 nights, plus 4 hours per day of
searching for signs; with all survey effort repeated in a 2nd survey.
Page 3 of 5
Targeted species survey guidelines: Dasycercus blythi
Ethical and handling considerations
Check traps early in the morning before temperatures become too hot.
Close or move traps with lots of ants.
Trapped animals should be protected from temperature extremes and exposure (heat, cold,
dehydration). Provide shelter in the bottom of pitfalls e.g. some leaf litter or a 35 mm piece of PVC pipe
(this also reduces predation for captured animals). Position Elliott traps under cover (e.g. under spinifex
hummock) where possible or provide shelter (e.g. leaf litter or even a shovel-load of sand on top of the
Elliott trap).
Ensure that individual mulgara are not trapped for four nights consecutively; fur-clip captures and close
traps after three nights if recaptures occur.
Consider weed and pathogen spread when using equipment in multiple locations as these can be
transported via dirty equipment.
Gloves should be worn when handling scats to reduce exposure to zoonotic diseases.
Acknowledgements
These guidelines were prepared by Melanie Venz in June 2012. Advice and comments on drafts for
Dasycercus blythi was provided by Pip Masters.
Citation
Venz, M. 2012. Brush-tailed mulgara, Dasycercus blythi. Targeted species survey guidelines. Queensland
Herbarium, Department of Science, Information Technology and Innovation, Brisbane.
Key references
DSEWPaC (2011). Survey Guidelines for Australia's Threatened Mammals. (Department of Sustainability,
Environment, Water, Population and Communities: Canberra, Australia).
Dickman, C. R., Haythornthwaite, A. S., McNaught, G. H., Mahon, P. S., Tamayo, B., and Letnic, M. (2001).
Population dynamics of three species of dasyurid marsupials in arid central Australia: a 10-year study. Wildlife
Research, 28, 493-506.
Dickman, C.R., Greenville, A.C., Tamayo, B. and Wardle, G.M. (2011). Spatial dynamics of small mammals in
central Australian desert habitats: the role of drought refugia. Journal of Mammalogy. 92, 1193-1209.
Gibson, D. F., and Cole, J. R. (1992). Aspects of the ecology of the mulgara, Dasycercus cristicauda
(Marsupialia: Dasyuridae) in the Northern Territory. Australian Mammalogy, 15, 105-112.
Greenville, A.C., Wardle, G.M. and Dickman, C.R. (2012). Extreme climatic events drive mammal irruptions:
regression analysis of 100-year trends in desert rainfall and temperature. Ecology and Evolution 2(11), 26452658.
Körtner, G., Pavey, C.R. and Geiser, F. (2007). Spatial ecology of the mulgara in arid Australia: impact of fire
history on home range size and burrow use. Journal of Zoology. 273, 350-357.
Letnic, M., and Dickman, C. R. (2005). The responses of small mammals to patches regenerating after fire and
rainfall in the Simpson Desert, central Australia. Austral Ecology, 30, 24-39.
Page 4 of 5
Targeted species survey guidelines: Dasycercus blythi
Masters, P. (2012). Brush-tailed mulgara, Dasycercus blythi. In 'Queensland's Threatened Animals' (Eds L. K.
Curtis, A. J. Dennis, K. R. McDonald, P. M. Kyne and S. J. S. Debus) pp. 334-335 (CSIRO Publishing:
Collingwood).
Masters, P., and Dickman, C. R. (2012). Population dynamics of Dasycercus blythi (Marsupialia: Dasyuridae)
in central Australia: how does the mulgara persist?. Wildlife Research, 39, 419-428.
Masters, P., Dickman, C. R., and Crowther, M. (2003). Effects of cover reduction on mulgara Dasycercus
cristicauda (Marsupialia: Dasyuridae), rodent and invertebrate populations in central Australia: implications for
land management. Austral Ecology, 28(6), 658-665.
Meek, P.D., Ballard, G., and Fleming, P. (2012). An introduction to camera trapping for wildlife surveys in
Australia. PestSmart Toolkit Publication, Invasive Animals Cooperative Research Centre, Canberra, Australia.
Menkhorst, P., and Knight, F. (2011). A field guide to the mammals of Australia. 3rd edn. Oxford University
Press, Melbourne.
Mills, D. J., Harris, B., Claridge, A. W., and Barry, S. C. (2002). Efficacy of hair-sampling techniques for the
detection of medium-sized terrestrial mammals. I. A comparison between hair-funnels, hair-tubes and indirect
signs. Wildlife Research, 29(4), 379-387.
Moseby, K., Nano, T. and Southgate, R. (2012). Tales in the sand: a guide to identifying Australian arid zone
fauna using spoor and other signs. 3rd edn. Ecological Horizons, South Australia.
Nelson, J. L. (2006). A comparison of three hair-tube types for the detection of the spotted-tailed quoll
Dasyurus maculatus in south-eastern New South Wales. Australian Mammalogy, 28(2), 229-233.
Pavey, C. R., Burwell, C. J., Körtner, G., and Geiser, F. (2009). Vertebrate diet decreases winter torpor use in
a desert marsupial. Naturwissenschaften, 96(6), 679-683.
Pavey, C.R., Nano, C.E.M., Cooper, S.J.B., Cole, J.R. and McDonald, P.J. (2011). Habitat use, population
dynamics and species identification of mulgara, Dasycercus blythi and D. cristicauda, in a zone of sympatry in
central Australia. Australian Journal of Zoology 59, 156-169.
Triggs, B. (2004). Tracks, scats and other traces – a field guide to Australian mammals. Revised edition.
(Oxford University Press: Australia).
Vine, S.J., Crowther, M.S., Lapidge, S.J., Dickman, C. R., Mooney, N., Piggott, M.P., and English, A.W.
(2009). Comparison of methods to detect rare and cryptic species: a case study using the red fox (Vulpes
vulpes). Wildlife Research, 36, 436-446.
Woolley, P. A. (1990). Mulgaras, Dasycercus cristicauda (Marsupialia: Dasyuridae); their burrows, and records
of attempts to collect live animals between 1966 and 1979. Australian Mammalogy, 13, 61-64.
Woolley, P.A. (2005). The species Dasycercus Peters, 1875 (Marsupialia: Dasyuridae). Memoirs of Museum
Victoria 62, 213-221.
Woolley, P.A. (2008). Brush-tailed mulgara, Dasycercus blythi. In ‘The Mammals of Australia’. (Eds S. Van
Dyck and R. Strahan) pp. 47-48 (Reed New Holland: Sydney).
Page 5 of 5