Survey guidelines for Australia’s threatened non-flying mammals

Southern brown bandicoot

Isoodon obesulus obesulus

States and territories: NSW, Victoria, Tasmania, South Australia and Western Australia.

Regions: NSW – south-eastern (Braithwaite 1995);

Victoria – approximately 150 metre wide strip along the coast (Braithwaite 1995)

South Australia – four regions, including the Mount Lofty Ranges, the southeast and Kangaroo Island (status on the Eyre Peninsular is uncertain) (Paull 1995)

Tasmania – widespread, absent from all islands except Bruny Island and West Sisters Island in the Furneaux Group. It has been introduced to Maria Island (Rounsevell et al 1991)

Western Australia – south-eastern region (Braithwaite 1995).

Habitat: Various – forest, heath, swamp and coastal scrub with sandy soil and scrubby ground-cover vegetation, particularly in areas which are subject to intermittent fires (Braithwaite 1995).

Habit: Ground-dwelling.

Avg. body weight: 850 g males and 700 g females (Braithwaite 1995).

Activity pattern: Nocturnal.

Diet: Omnivore: invertebrates, tubers and fungi (Braithwaite 1995).

Breeding: Breeding from winter to late summer, with two to four litters of between three and four young (Braithwaite 1995).

Description

Three subspecies of the southern brown bandicoot occur within a fragmented but widespread distribution across Australia as follows:

• 
  I. o. obesulus from southern Western Australia, South Australia, Victoria, NSW and Tasmania
  
• 
  I. o. nauticus from Nyuts Archipelago off the South Australian coast, and
  
• 
  I. o. peninsulae from the east coast of Cape York, Queensland.
  

Southern mainland populations will be treated as I. o. obesulus in this report but see Pope and colleagues (2001) and Zenger and colleagues (2005) for discussion about southern brown bandicoot taxonomy.

The southern brown bandicoot prefers open forest, heath and swamp habitats (Cooper 1998), particularly with a mosaic of patches with different burning histories (Braithwaite 1995). Fire increases the diversity of resources like plants, insects and fungi that provide food and are necessary for population growth and increased fecundity in this species (Braithwaite 1995). Individuals shelter in nests constructed from plant matter in leaf litter or dense understorey vegetation during the day, and at night forage on insects and fungi (Braithwaite 1995). This species appears to have a high degree of morphological and behavioural plasticity. For example, Cooper (1998) noted that bandicoots from open forests were on average larger than those from swamp-reed habitats. Lobert and Lee (1990) found differences in the timing and length of the breeding season, the number of litters produced per season and the rates of growth in populations of the southern brown bandicoot from Tasmania and Victoria. Paull (1995) found that southern brown bandicoot habitat is sensitive to fire management regimes and that over-frequent fire removes the preferred microhabitats for this species.

Survey methods

On the basis of previous surveys, the following survey techniques are recommended to detect the presence of the southern brown bandicoot in areas up to 5 hectares in size:

• 
  daytime searches for potentially suitable habitat, such as areas with a dense understorey and thick ground-cover, perhaps focussing on areas where fire has produced a mosaic of habitats that vary according to the time since burning (description of the survey technique and recommended effort is outlined in Section 3.1)
  
• 
  daytime searches for signs of activity, including tracks, scats, nests and diggings (description of the survey technique and recommended effort is outlined in Section 3.2). However, where the southern brown bandicoot occurs in sympatry with other bandicoot species, direct detection techniques should be used to distinguish between the species
  
• 
  collection of predator scats, owl casts or remains, targeting predatory bird/mammal nests/dens (description of the survey technique and recommended effort is outlined in Section 3.2)
  
• 
  soil plot surveys conducted according to the description of the technique and the recommended effort provided in Section 3.3.2
  
• 
  spotlight surveys conducted according to the description of the technique and the recommended effort provided in Section 3.3.3
  
• 
  hair sampling surveys (including the use of baited open tubes) with ten hair tunnels per hectare set in areas showing evidence of recent diggings and suitable habitat. These surveys should be conducted in autumn, according to the description of the technique provided in Section 3.3.7. A minimum of two surveys, each of 14 day duration, should be conducted, timed at least one month apart and at least one undertaken following significant rainfall
  
• 
  baited camera traps using universal bait (description of the survey technique is outlined in section 3.3.6) using one camera per hectare. Autumn is preferred, but can be year round if validated with supporting evidence. A minimum of two surveys, each of 14 day duration, should be conducted, timed at least one month apart and at least one undertaken following significant rainfall
  
• 
  community liaison to detect the location of additional populations of the species.
  

It is recommended that hair sampling surveys be conducted to distinguish between bandicoot species in a staged detection process, with initial effort focussing on searching for signs and soil plot surveys. Conducted in concert with baited camera traps, the efficacy of survey effort is likely to increase.

Live trapping (using cage traps) is not recommended to determine presence due to its inefficiency (southern brown bandicoot are often considered to be "trap shy") and the tendency of females to eject pouch young when trapped.

Similar species in range

The southern brown bandicoot occurs in sympatry with two species of bandicoot, including the long-nosed bandicoot Perameles nasuta on mainland eastern Australia and the eastern barred bandicoot Perameles gunnii in Tasmania.

The longer nose and larger ears of the long-nosed bandicoot distinguish it from the southern brown bandicoot. The white striped fur on the rump of the eastern barred bandicoot distinguishes this species from the southern brown bandicoot, which has a uniformly brown/grey coloured pelage. Furthermore, the southern brown bandicoot occurs in sympatry with several Potorous spp, which produce similar but smaller and more conical foraging pits (usually indistinguishable in the field to all but experienced observers). The distribution of the southern brown bandicoot overlaps with the long-nosed potoroo Potorous tridactylus along east coast mainland and Tasmania, Gilbert's potoroo Potorous gilbertii in Two Peoples Bay, Western Australia, and the long-footed potoroo Potorous longipes in north-eastern Victoria and adjacent area of ACT and NSW. The forepaw tracks of bandicoots are distinguished from those made by potoroos by the presence of three rather than five digits (B Triggs pers. comm.).
References

Braithwaite, R.W. 1995. southern brown bandicoot Isoodon obesulus. In ‘The Mammals of Australia’. Ed. Strahan, R. pp. 176-177 (Reed Books: Sydney).

Catling, P.C., Burt, R.J. and Kooyman, R. 1997. A comparison of techniques used in a survey of the ground-dwelling and arboreal mammals in forests in north-eastern New South Wales. Wildlife Research 24: 417-432.
Catling, P.C., Coops, N.C and Burt, R.J. 2001. The distribution and abundance of ground-dwelling mammals in relation to time since wildfire and vegetation structure in south-eastern Australia. Wildlife Research 28: 555-564.
Claridge, A. (2009). DECCW. Personal communication regarding the Southern-brown bandicoot.
Claridge, A.W. and Barry, S.C. 2000. Factors influencing the distribution of medium-sized ground-dwelling mammals in southeastern mainland Australia. Austral Ecology 25: 672-688.
Cooper, M.L. 1998. Geographic variation in size and shape in the southern brown bandicoot, Isoodon obesulus (Peramelidae: Marsupialia), in Western Australia. Australian Journal of Zoology 46: 145-152.
Lobert, B. and Lee, A. K. 1990. Reproduction and life history of Isoodon obesulus in Victorian heathland. In Bandicoots and Bilbies. Eds. Seebeck, J.H., P.R. Brown, R.L. Wallis and C.M. Kemper. pp. (Surrey Beatty and Sons: Sydney).
Paull, D. 1995. The distribution of southern brown bandicoot (Isoodon obesulus obesulus) in South Australia. Wildlife Research 22: 585-600.
Paul, D. 2008. southern brown bandicoot Isoodon obesulus. In ‘The Mammals of Australia’. (Eds. S. Van Dyck and R. Strahan) pp. 180-182 (Reed New Holland: Sydney).
Pope, L., Storch, D., Adams, M., Moritz, C. and Gordon, G. 2001. A phylogeny for the genus Isoodon and a range extension for I. obesulus peninsulae based on mtDNA control region and morphology. Australian Journal of Zoology 49: 411-434.
Rees, M. and D. Paull. 2000. Distribution of the southern brown bandicoot (Isoodon obeslus) in the Portland region of south-western Victoria. Wildlife Research 27: 539-545.
Rounsevell, D.E., Taylor, R. and Hocking, R. 1991. Distribution of Native Terrestrial Mammals in Tasmania. Wildlife Research 18:699-717.
Sanderson, K.J. and Kraehenbuel, J. 2006. southern brown bandicoots Isoodon obesulus obesulus in Belair National Park. Australian Mammalogy 28(2): 147-152.
Triggs, B. (2009). Dead Finish. Personal communication regarding the southern brown bandicoot.
Zenger, K.R, Eldridge, M.K., and Johnston, P.G. 2005. Phylogenetics, population structure and genetic diversity of the endangered southern brown bandicoot (Isoodon obesulus) in south-eastern Australia. Conservation Genetics 6: 193-204.