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Long-nosed Potoroo

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The Long-nosed Potoroo (Potorous tridactylus) is a member of the Rat-Kangaroo family (Potoroidae), meaning they are more closely related to other macropods (Kangaroos and Wallabies) than to the Bandicoots they can superficially resemble.

If you’re lucky enough to get a close look, you will see their hind feet closely resemble that of other macropods and they are more than capable of hopping at speed into thick vegetation cover when they feel threatened. The Long-nosed Potoroo ranges in weight from 660g up to 1640g (1) and is one of the smallest members of its family (2).  Long-nosed potoroos are nocturnal and solitary but non-territorial (3, 4, 5, 6). Males have been found to be significantly larger than females with respect to head length, foot length and bodyweight (6). As with all marsupials, the Long-nosed Potoroo gives birth to tiny, underdeveloped young after a short gestation period and this joey continues the rest of its development in the pouch of its mother. Female Long-nosed Potoroos are known to produce a single young per litter with a pouch life of approximately four months (2, 7).

Habitat

In Victoria, the Long-nosed Potoroo occurs in six discrete regions, including the south-western region, Grampians, Otways, Western Port, Wilsons Promontory and east Gippsland (8).  Within its geographic range, which generally corresponds with areas of rainfall >760mm, the Long-nosed Potoroo has been found in a wide variety of forest types (9). In the forest types where they have been detected, dense ground cover is a distinctive feature (8, 9, 10, 11). This cover likely assists the Potoroo’s in a variety of ways such as providing shelter sites throughout the day and protection from both terrestrial and airborne predators (9).  However, it has been found that the foraging activity of Potoroo’s is greatest in areas where the understorey vegetation is less dense (9). Therefore, a patchwork of habitat types and ground cover densities is likely to be best for Long-nosed Potoroo survival, allowing them to seek shelter throughout the day (in the densely covered areas) and forage throughout the night (in more open habitats) (9). The home range estimates for Long-nosed Potoroo’s differ between genders, with males ranging somewhere between 2-4ha while females occupy smaller ranges of 1.5-3ha (4, 6, 12).

Diet (and its importance to the ecosystem!)

Throughout the year, the foraging patterns of Long-nosed Potoroos are dynamic, meaning they exploit a range of locations throughout their range for food resources that change throughout the year (13, 14).  So a Potoroo’s diet will change seasonally, ranging from fungi and seeds throughout Autumn and Winter through to invertebrates and fruit during Spring and Summer (15).  Much of the food consumed by the Long-nosed Potoroo is obtained underground, so these creatures are well adapted to digging shallow excavations in the litter and soil using their long, well developed claws (15).  Potoroo’s eat many types of food such as bulbs, tubers, roots, fruit and invertebrates, but… it is fungi that they favour most of all (15, 16). The Long-nosed Potoroo’s highly developed sense of smell makes them incredibly good at detecting and unearthing a range of fungi species for consumption (17). Importantly, many species of fungi consumed by Potoroo’s, lack active mechanisms for spore dispersal and the fungi are therefore dependent upon animals to spread their spores (15).  The fungi consumed by potoroos are thought to form beneficial mycorrhizae on trees (particularly Eucalyptus sp.) and shrubs, so it is very likely that the Long-nosed Potoroo plays a critical role in the dispersal and colonisation of environmentally important fungi throughout its range (14, 18).

Threats

Considering the preference of Long-nosed Potoroo’s for dense ground cover for shelter and more open areas for foraging, the protection of habitats with varying vegetation structure and diversity will be critical for the continued survival of this species. The historical habitat range of the Long-nosed Potoroo has declined greatly over the last 200 years since European settlement as a result of habitat loss/fragmentation for agriculture and human settlement, altered fire regimes and overgrazing by stock (19).  In addition, Long-nosed Potoroo’s are predated upon by a wide variety of animals both native (Tiger Quolls, Owls, Raptors, Dingoes) and introduced (Foxes and Cats) (9). Unfortunately, there is evidence that suggests the efficient hunting skills of the fox are not impeded by the dense understory vegetation that Potoroo’s rely upon for shelter (17, 18).  If effective fox control measures are in place it appears that the abundance of Long-nosed Potoroo’s can rebound (7, 21, 22).  However, it is likely that cat control must also be in place to give these animals the best chance of continued survival because when foxes alone are removed cat numbers increase in the absence of their competitors (23, 24).  Altogether, predation by introduced predators, habitat loss/ modification and inappropriate fire regimes are believed to be major contributors to the decline of Long-nosed Potoroos (3, 25).

So the Long-nosed Potoroos of the Otways need our help to overcome the pressures mounted against them and continue their vital role in the environment!  Please report any sightings of this marvellous mini-macropod to our threatened species hotline:

0 ‘I SPOTTED’ 1 (0 4 7768833 1)

Things to look for:

  • Fur of a chocolatey/dark brown colour
  • An animal that appears like an oversized rat (hence rat-kangaroo)
  • Hopping gait when moving fast
  • Long-ish nose (if you can see it!)

References:

  1. Johnston, P. G. (2008). Long-nosed potoroo. In ‘The Mammals of Australia’. (Eds S. van Dyck and R. J. Strahan.) pp. 302– (Reed New Holland: Sydney.)
  2. Norton, M.A. et al. (2010a) Habitat Associations of the long-nosed potoroo (Potorous tridactylus) at multiple spatial scales, Australian Journal of Zoology58, 303-316
  3. Seebeck, J. H., Bennett, A. F., and Scotts, D. J. (1989). Ecology of the Potoroidae – a review. In ‘Kangaroos, Wallabies and Rat-kangaroos’. (Eds G. Grigg, P. Jarman and I. Hume.) pp. 67– (Surrey Beatty: Sydney.)
  4. Long, K. I. (2001). Spatio-temporal interactions among male and female long-nosed potoroos, Potorous tridactylus (Marsupialia: Macropodoidea): mating system implications. Australian Journal of Zoology 49, 17– doi:10.1071/ZO00077
  5. Johnston, P. G. (2008). Long-nosed potoroo. In ‘The Mammals of Australia’. (Eds S. van Dyck and R. J. Strahan.) pp. 302– (Reed New Holland: Sydney.)
  6. Norton, M.A. et al. (2010b) Population Biology of the long-nosed potoroo (Potorous tridactylus) in the Southern Highlands of New South Wales, Australian Journal of Zoology, 58, 362-368
  7. Claridge, A. W., Seebeck, J., and Rose, R. (2007). ‘Bettongs, Potoroos and the Musky Rat-kangaroo.’ (CSIRO Publishing: Melbourne.)
  8. Seebeck, J.H. (1981) Potorous tridactylus (Kerr) (Marsupialia : Macropodidae): its Distribution, Status and Habitat Preferences in Victoria, Australian Wildlife Research8, 285-306
  9. Bennett, A.F. (1993) Microhabitat Use by the Long-nosed Potoroo, Potorous tridactylus, and other Small Mammals in Remnant Forest Vegetation of South-western Victoria, Wildlife Research20, 267-85
  10. Menkhorst, P. W., and Beardsell, C. M. (1982). Mammals of southwestern Victoria from the Little Desert to the coast. Proceedings of the Royal Society of Victoria 94, 221-47.
  11. Amos, P.J. (1983) The potoroo in Queensland, Queensland Agricultural Journal 108, 5-6
  12. Bennett, A.F. (1987) Conservation of Mammals within a fragmented forest environment: the contributions of insular biogeography and autecology. In ‘Nature Conservation: The Role of Remnants of Native Vegetation’. (Eds D.A. Saunders, G.W. Arnold, AA Burbidge and AJM Hopkins.) pp. 41-52 (Surrey Beatty: Sydney)
  13. Claridge, A.W., Cunningham, R.B., Tanton, T. (1993a) Foraging patterns of the long-nosed potoroo (Potorous tridactylus) for hypogeal fungi in mixed-species and regrowth eucalypt forest stands in southeastern Australia, Forest Ecology and Management, 61, 75-90
  14. Claridge, A.W., Tanton, M.T., Cunningham, R.B. (1993b) Hypogeal fungi in the diet of the long-nosed potoroo (Potorous tridactylus) in Mixed-species and Regrowth Eucalypt Forest Strands in South-eastern Australia, Wildlife Research, 20, 321-37
  15. Bennett, A.F. and Baxter, B.J. (1989) Diet of the Long-nosed Potoroo, Potoroo tridactylus, (Marsupialia: Potoroidae), in South-western Victoria, Australian Wildlife Research16, 263-71.
  16. Schlager, F. E. (1981). The distribution and status of the rufous rat-kangaroo, Aepyprymnus rufescens, and the long-nosed potoroo, Potorous tridactylus, in northern New South Wales. Univ. New England, Armidale, N.S.W., Dep. Ecosystem Manage. Project Rep. No.
  17. Vernes, K, and Jarman, P. (2014) Long-nosed potoroo (Potorous tridactylus) behaviour and handling times when foraging for buried truffles, Australian Mammalogy36, 128-130
  18. Claridge, A. W. (1992). Is the relationship among mycophagous marsupials, mycorrhizal fungi and plants dependent on fire? Australian Journal of Ecology 17, 223-5.
  19. Norton, M.A., Prentice, A. Dingle, J., French, K., Claridge, A.W. (2015) Population characteristics and management of the long-nosed potoroo (Potorous tridactylus) in high-quality habitat in the Southern Highlands of New South Wales, Australian Mammalogy37, 67-74.
  20. Short, J. S. (1998). The extinction of rat-kangaroos (Marsupialia: Potoroidae) in New South Wales, Australia. Biological Conservation 86, 365–377. doi:10.1016/S0006-3207(98)00026-3
  21. Murray, A. J., Poore, R. N., and Dexter, N. (2006). Project Deliverance – the response of ‘critical weight range’ mammals to effective fox control in mesic forest habitats in far east Gippsland, Victoria. Department of Sustainability and Environment, Melbourne.
  22. Dexter, N., and Murray, A. (2009). Impact of fox control on the relative abundance of forest mammals in East Gippsland, Victoria. Wildlife Research 36, 252– doi:10.1071/WR08135
  23. Christensen, P., and Burrows, N. (1995). Project Desert Dreaming: experimental reintroduction of mammals to the Gibson Desert, Western Australia. In ‘Reintroduction Biology of Australian and New Zealand Fauna’. (Ed. M. Serena.) pp. 199– (Surrey Beatty: Sydney.)
  24. Risbey, D. A., Calver, M. C., Sort, J., Bradley, J. S., and Wright, I. W. (2000). The impact of cats and foxes on the small vertebrate fauna of Hierisson Prong, Western Australia. II. A field experiment. Wildlife Research 27, 223–235. doi:1071/WR98092
  25. Claridge, A. W., and Barry, S. C. (2000). Factors influencing the distribution of medium-sized ground-dwelling mammals in south-eastern mainland Australia. Austral Ecology 25, 676– doi:10.1111/j.1442-9993.2000.tb00074.x