Survey guidelines for Australia’s threatened non-flying mammals

Mountain pygmy possum

Burramys parvus

States and territories: Victoria and NSW.

Regions: Alpine regions.

Habitat: Rock scree or boulder fields supporting characteristic communities of subalpine heath dominated by the mountain plum pine Podocarpus lawrencei and adjacent habitats such as Poa-Carex sedgeland above 1400 m (Mansergh & Broome 1994). Dispersing juveniles may range into peripheral habitats generally at lower altitudes, such as the snow gum Eucalyptus pauciflora zone (Mansergh 1995). The total extent of primary habitat is less than 6 square kilometres (Broome 2008).

Habit: Ground-dwelling, utilises rock crevices in boulder fields.

Avg. body weight: 41 g (males), 42 g (females) (Broome 2008).

Activity pattern: Nocturnal and seasonal (hibernates during winter).

Diet: Omnivorous: arthropods (particularly the bogong moth Agrotis infusa); seeds and fruits, particularly of the mountain plum pine and snow-beard heath Leucopogon montanus (Mansergh et al. 1990).

Breeding: A single litter, usually of four young, is born in late spring to early summer following snow melt (Broome 2008). Young are carried in the pouch for about one month and then deposited in a nest with first individuals leaving the nest in early January (Mansergh 1995).

Description

The mountain pygmy possum is a small possum with mid-grey coloured fur that is lighter ventrally and slightly brown on its back (Menkhorst and Knight 2004). It is the only mammal that is restricted in distribution to the Australian alpine and sub-alpine regions and is confined to one of the smallest ranges (less than 6 square kilometres) of any Australian mammal. Within these regions, the species occurs only in small patches of rock scree in periglacial blockfields and blockstreams, above altitudes of 1400 metres where there is continuous snow cover for at least six months of the year (Broome 2008).

The mountain pygmy possum is a highly seasonal species, which breeds in summer and hibernates in winter when its habitat is covered in snow (April to October) (Broome 2008). During the summer months, the species eats mostly arthropods and fruits, particularly exploiting the abundance of bogong moths during their summer migration to the highland regions (Broome 2001). After the end of the breeding period in March, the possums gain weight rapidly and begin to store food for the anticipated winter torpor.

Survey methods

On the basis of previous surveys, the following survey techniques are recommended to detect the presence of the mountain pygmy possum in areas up to 5 hectares in size:

• 
  location of primary habitat (that is, rock scree and boulder fields) with mountain plum pine dominated sub-alpine shrubland through examining fine-scale vegetation mapping (where available), aerial photography and ground-truthing (description of the survey technique and recommended effort is provided in Section 3.1)
  
• 
  location of distinctively chewed mountain plum pine seeds that are cracked transversely (as opposed to lengthwise in the sympatric bush rat, Rattus fuscipes; Triggs 1996)
  
• 
  collection of predator scats (particularly introduced predators) (note: this is limited: even if detected the prey may have originated anywhere within a large radius; for example, 30 kilometres for dogs) (description of the survey technique and recommended effort is provided in Section 3.2)
  
• 
  hair sampling device surveys, following the description of the technique and recommended effort provided in Section 3.3.7, as the species is included among those known to be distinguishable from hair samples (see Table 2, Section 3.3.7), and
  
• 
  Elliott A or E trapping surveys are the recommended primary technique, conducted according to the description of the technique and recommended effort provided in Section 3.3.9 (baiting the traps with walnuts), but to be consistent with previous studies on the mountain pygmy possum, increase the survey effort as follows:
  

• 
  in areas of suitable alpine habitat, use four rather than two survey sites per five hectare area (the minimum number of sites specified in Section 3.3.9)
  
• 
  sample during the warmer months of the year
  
• 
  set 25 traps in each survey site, spaced at 5 metres intervals in boulder field and adjacent alpine heathland habitats
  

• 
  use of camera traps, such as in artificially constructed habitat connecting discontinuous primary habitat (such as road underpasses).
  

An additional consideration for survey design is that the mountain pygmy possum sexually segregates within the boulder field habitat, with the large adult females occupying the preferred breeding habitat closest to the boulder field, and adult males and juveniles found at lower elevations (Broome 2001). However, in some populations this scenario does not appear to occur, for example the habitat occupied by males at Timms Spur in the Victorian Alps remains problematic despite extensive trapping. The location of migrating individuals at lower elevations, particularly juveniles after February, needs to be taken into account when establishing survey sites. If the subject site includes both boulder scree and alpine heathland, then to ensure both habitat types are sampled a trapping gradient placed along an altitudinal gradient may be appropriate. Note that dispersing juveniles may also occur in atypical adjacent habitat, although the importance of such vegetation types is poorly understood.

Similar species in range

No other small possum species occur within the mountain pygmy possum's range. However, there is potential for the eastern pygmy possum Cercartetus nanus to occur in areas where dispersing mountain pygmy possum move into the snow gum zone. The mountain pygmy possum can be readily identified by the presence of enlarged premolars and from other sympatric small ground-dwelling mammals by the syndactyle hindfeet (that is, second and third toes are fused) (Mansergh & Broome 1994).

References

Broome, L. S. 2001. Density, home range, seasonal movements and habitat use of the mountain pygmy-possum Burramys parvus (Marsupialia: Burramyidae) at Blue Cow, Kosciusko National Park. Austral Ecology 26: 275 – 292.
Broome, L. S. 2008. Mountain Pygmy-Possum Burramys parvus. In ‘The Mammals of Australia’ (Ed. S. Van Dyck and R. Strahan) pp. 210 – 212. (Reed New Holland: Sydney).
Broome, L. S. and Geiser, F. 1995. Hibernation in free-living Mountain Pygmy-possums Burramys parvus (Marsupialia: Burramyidae). Australian Journal of Zoology 43: 373 – 379.
Heinze, D. and Williams, L. 1998. The discovery of the Mountain Pygmy-possum Burramys parvus on Mount Buller, Victoria. The Victorian Naturalist 115(4): 132 – 134.
Heinze, D. L., Broome, L. and Mansergh, I. 2004. A review of the ecology and conservation of the Mountain Pygmy-possum Burramys parvus Broom 1896 In ‘The Biology of Australian Possums and Gliders’. (Eds. R. L. Goldingay and S. M. Jackson.) pp. 254 – 267. (Surrey Beatty, Sydney.)
Mansergh, I. M. 1995. Mountain Pygmy-possum Burramys parvus. In ‘Mammals of Victoria: distribution, ecology and conservation’ (Ed. P.W. Menkhorst) pp. 95 – 96. (Oxford University Press, Melbourne).
Mansergh, I., Baxter, B., Scotts, D., Brady, T. and Jolley, D. 1990. Diet of Burramys parvus (Marsupialia: Burramyidae) and other small mammals in the alpine environment at Mount Higginbotham, Victoria. Australian Mammalogy 13: 167 – 177.
Mansergh, I. and Broome, L. 1994. The Mountain Pygmy-possum of the Australian Alps. (New South Wales University Press, Sydney).
Mansergh, I.M and Scotts, D.J 1989. Habitat continuity and social organisation of the Mountain pygmy-possum restored by tunnel. Journal of Wildlife Management 53(3): 701 – 707.
Menkhorst, P. and Knight, F. 2004. A Field Guide to the Mammals of Australia. Second Edition. (Oxford University Press, Melbourne).
Triggs, B. 1996. Tracks, scats and other traces: a field guide to Australian mammals. (Oxford University Press, Melbourne).
Warneke, R.M. 1967. Discovery of a living Burramys. Bulletin of the Australian Mammal Society 2: 94 – 95.