The Threatened Species Scientific Committee agreed that this species was eligible to be retained as vulnerable on 2 December 2010

Advice from the Threatened Species Scientific Committee (the Committee) on the list of Threatened Species under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)

1. Reason for Conservation Assessment by the Committee This advice follows assessment of new information on: Isoodon obesulus nauticus ( ( subspecies))

2. Summary of Species Details Taxonomy The subspecies Isoodon obesulus nauticus is recognised by Thomas (1922) and Robinson et al., (2000). State Listing Status This subspecies is listed as vulnerable under the National Parks and Wildlife Act 1972. Description The southern brown bandicoot has coarse dark greyish or yellowish fur above and white fur below. The tail and upper surface of the feet are usually dark brown. This subspecies is paler in colour and markedly smaller than the mainland subspecies, weighing 600 g (males) and 530 g (females) when mature (Copley et al., 1990). Distribution The subspecies occurs on East and West Franklin Islands and , in the Nuyts Archipelago, off the west coast of South

Australia’s . Relevant Biology/Ecology The southern brown bandicoot (Nuyts Archipelago subspecies) is a crepuscular and nocturnal marsupial that prefers thick vegetation cover. Like the mainland subspecies, the Nuyts Archipelago subspecies probably breeds opportunistically and is capable of a high reproductive rate under favourable conditions. However, mortality of juveniles and young is very high (Copley et al., 1990). Threats Known The main identified threats to the southern brown bandicoot (Nuyts Archipelago subspecies) include habitat changes; and their susceptibility to stochastic events, as a result of the subspecies extremely limited distribution and small population sizes (Kemper, 1990; Maxwell et al., 1996). The spread of the introduced weed Crystalline iceplant (Mesembryanthemum crystallinum) on each of the islands (Lee, 1995) is of concern. Crystalline iceplant inhibits the growth of native plants by accumulating salt in the soil and by leaving behind mats of dry plant matter that may take several years to decompose. There is reason for concern in the longer term that the islands, particularly Franklin Island, may become increasingly dominated by iceplant and other salt tolerant species and less by perennial shrubs (Read, 1984). Potential In addition to known threats cited above, potential threats include the establishment of feral animals, Felis catus (feral cats) and Vulpes vulpes (European red xoxes) on the islands (Sautter, pers. comm., 2010).

Isoodon obesulus nauticus (southern brown bandicoot (Nuyts Archipelago subspecies)) Listing Advice Page 1 of 4 The Threatened Species Scientific Committee agreed that this species was eligible to be retained as vulnerable on 2 December 2010

3. Public Consultation Notice of the proposed amendment was made available for public comment for 30 business days. Any comments received that are relevant to the survival of the species have been considered by the Committee.

4. How judged by the Committee in relation to the EPBC Act criteria and Regulations Criterion 1: It has undergone, is suspected to have undergone or is likely to undergo in the immediate future a very severe, severe or substantial reduction in numbers Not eligible

Criterion element Evidence Reduction in numbers Insufficient data – This species is thought to have declined in numbers on St Francis Island as a result of land clearing and degradation, but no quantitative data are available (Maxwell et al., 1996). Subfossil evidence also suggests the Southern Brown Bandicoot (Nuyts Archipelago subspecies) previously occurred on Flinders Island and Reevesby Island (Paull, 1995). Given records of historical decline and a lack of data on recent population trends and numbers (within the past 14 years), there are insufficient data available to determine whether reductions in population numbers have been or would be substantial.

Criterion 2: Its geographic distribution is precarious for the survival of the species and is very restricted, restricted or limited Not eligible

Criterion element Evidence Geographic distribution Very restricted – The extent of occurrence is estimated to be approximately 13 km2 and the area of occupancy is likely to be AND slightly less (Maxwell et al., 1996). Geographic distribution Insufficient data – This species is known from only three locations; precarious East and West Franklin Islands and St Francis Island in the Nuyts Archipelago, South Australia (Maxwell et al., 1996). As the three known populations occur on isolated islands its distribution is considered to be severely fragmented. Given a lack of data on recent population trends and the impact of known threats, there are insufficient data to determine continuing decline and therefore, determine the precariousness of this species distribution.

Criterion 3: The estimated total number of mature individuals is very low, low or limited; and either (a) evidence suggests that the number will continue to decline at a very high, high or substantial rate; or (b) the number is likely to continue to decline and its geographic distribution is precarious for its survival Not eligible

Isoodon obesulus nauticus (southern brown bandicoot (Nuyts Archipelago subspecies)) Listing Advice Page 2 of 4 The Threatened Species Scientific Committee agreed that this species was eligible to be retained as vulnerable on 2 December 2010

Criterion element Evidence Total no. of mature Insufficient data – The most recent data available indicates an individuals estimated total population size of 1500 individuals (Maxwell et al., 1996). AND Continued rate of decline Insufficient data – See Criterion 1 OR Total no. of mature Low – The most recent data available indicates an estimated total individuals population size of 500 individuals (Maxwell et al., 1996). AND Continued decline likely Insufficient data – See Criterion 2 AND Geographic distribution Insufficient data – See Criterion 2 precarious

Criterion 4: The estimated total number of mature individuals is extremely low, very low or low Eligible for listing as vulnerable

Criterion element Evidence Total no. of mature Low – The most recent data available indicates an estimated total individuals population size of 1500 individuals (Maxwell et al., 1996).

Criterion 5: Probability of extinction in the wild that is at least (a) 50% in the immediate future; or (b) 20% in the near future; or (c) 10% in the medium-term future Not eligible

Criterion element Evidence Probability of extinction in No data the wild

5. Recommendations The Committee recommends that no amendment be made to the list referred to in section 178 of the EPBC Act and that Isoodon obesulus nauticus remains eligible for inclusion in the vulnerable category of the list.

Threatened Species Scientific Committee 2 December 2010

Isoodon obesulus nauticus (southern brown bandicoot (Nuyts Archipelago subspecies)) Listing Advice Page 3 of 4 The Threatened Species Scientific Committee agreed that this species was eligible to be retained as vulnerable on 2 December 2010

6. References cited in the advice Copley P, Read V, Robinson A and Watts C (1990). Preliminary studies of the Nuyts Archipelago bandicoot Isoodon obesulus nauticus on the Franklin Islands, South Australia, in J. Seebeck, P. Brown, R. Wallis & C. Kemper (eds) (1990), Bandicoots and Bilbies, Surrey Beatty & Sons Pty Ltd, Chipping Norton. Kemper C (1990). Status of bandicoots in South Australia, in J. Seebeck, P. Brown, R. Wallis & C. Kemper (eds) (1990), Bandicoots and Bilbies, Surrey Beatty & Sons Pty Ltd, Chipping Norton. Lee AK (1995). The Action Plan for Australian Rodents, Australian Nature Conservation Agency, Goanna Print, Canberra. Maxwell S, Burbidge AA and Morris K (1996). The 1996 Action Plan for Australian Marsupials and Monotremes. Available on the Internet at: http://www.biodiversity.environment.gov.au/threaten/plans/action/marsupials/1.htm Paull D (1995). The Distribution of the Southern Brown Bandicoot (Isoodon obesulus obesulus) in South Australia. Wildlife Research 22: 585-600 Paull D (2008). Southern Brown Bandicoot (Isoodon obesulus), in S. Van Dyck, & R. Strahan, (eds), The Mammals of Australia (Third edition), Publishers (Australia) Pty Ltd. Pope LC, Storch D, Adams M, Moritz C and Gordon G. (2001). A phylogeny for the genus Isoodon and a range extension for Isoodon obesulus peninsulae based on mtDNA control region and morphology. Australian Journal of Zoology 49: 411–434. Read VT (1984). The Stick-nest Rats of Australia: A preliminary report. Deptartment of Environment and Planning, Adelaide. Robinson AC, Casperson KD and Hutchinson MN, (eds). (2000). A list of the Vertebrates of South Australia (Third Edition), Heritage and Biodiversity Division, Department for Environment and Heritage, Adelaide. Sautter E (2010) Personal communication, 23 September 2010. Ecologist, Threatened Flora, Department of Environment and Natural Resources, South Australia. Thomas (1922). Nuyts’ Islands Bandicoot (Isoodon Nauticus), in F. Wood Jones (1923). The mammals of South Australia – Part 1, Government Printer, Adelaide. Zenger KR, Eldridge MDB and Johnston PG (2005). Phylogenetics, population structure and genetic diversity of the endangered southern brown bandicoot (Isoodon obesulus) in south-eastern Australia. Conservation Genetics 6:193–204.

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