A Brief Scientific Data Analysis of Leadbeater’s Possum

Victoria’s Faunal Emblem (Australia)

Leadbeater’s Possum (Gymnobelideus leadbeateri) is a Critically Endangered (CR, acknowledging that population decreased by over 80%) possum who are geographically restricted to the central highlands of Victoria (Australia). They had been thought to be extinct (hadn’t been seen for 50 years) before they were rediscovered in 1961 (Lindenmayer 1995; Wilkinson 1961). I think this is because they are so tiny. Head and body length is about 150-170mm and about the same or a little bit longer length for their tails. Moreover, they are nocturnal and arboreal like other possums. So even if you had known that there were the possums in a Victoria’s central upland forest (dominated by the tallest flowering plant in the world!), it would have been still hard to see them.

Conservation Status

Leadbeater’s Possum was classified as CR on The IUCN Red List of  Threatened Species in 2014 (IUCN 2016). Before the assessment, they had been listed as Threatened, which includes Critically Endangered, Endangered and Vulnerable, for 31 years (IUCN 2016).

In response, there were scientists and conservationists who devoted themselves into preservation of the species for example, Professor David Lindenmayer at Australian National University. And of course, there are ongoing projects, and lots of efforts have been made by people.

Life History and Reproduction

They are monogamous and breed in winter and spring. Also they are polyoestrous, meaning that a second litter may be produced if the first is lost in a breeding season (Smith 1995). So they are pretty good at reproducing. Young are carried in the pouch for 80-93 days (they’re marsupial), before being left in the nest while the mother feeds for a further 5-40 days (Smith 1995). The average age at first emergence from the nest is about 111 days in captivity and 120 days in the wild (Smith 1995). At this stage wild animals weigh as little as 30-38 grams (Smith 1984, 1995). There are significantly different lifespans between the sexes, 7.5-11 years for males and 2.9-8 years for females (Smith 1995). This is due to several aspects. One is that males disperse their nests later (15 months) than females (10 months) (Smith 1995). Thus, males can learn and prepare more for their survivals. Also, there is a strange fact that males are accepted as non-breeding residents in neighbouring colonies or bachelor group (Smith 1995), so they don’t have to make their own nests while females have to establish theirs.

Importance of Mountain Ash (Eucalyptus regnans)

Mountain Ash (Eucalyptus regnans) is the tallest flowering plant in the world, among the tallest trees in the world, and is native to south-eastern Australia, mainly in Tasmania and Victoria.

Leadbeater’s Possum requires abundant uneven aged Mountain Ash, typically 190-400 years old or older because young trees don’t have hollows, which are used for nesting by Leadbeater’s Possums (Smith & Lindenmayer 1988; Lindenmayer et al 1991). The main factor of loss of Mountain Ash is logging and bushfire (IUCN 2016). Nevertheless, natural bushfire is required to maintain health of the forests. But problem is frequency and total area of potential habitat for the species. In other words, bushfire has been too frequent and habitat has been chopped down too much. In the terms of logging, 42,685 ha of Montane Ash forest in the central highlands has been logged in the past 40 years, including approximately 19,338 ha since late 1997.

Habitat and Population

As I mentioned above, they inhabit only in restricted forests. There are currently two habitats for the species, Yellingbo Conservation Reserve (Thomas 1989) and  Healesville-Marysville area (Lindenmayer et al 1989). However, fossil records suggest that they distributed along Great Dividing Range up to near Blue Mountains National Park in New South Wales (Broom 1895a, 1895b, 1896; Lindenmayer 1995; Hall 1974; Flood 1974; Wakefield 1967, 1972).

Population of Yellingbo Conservation Reserve is estimated at 40 individuals in 2014. However, there were 112 individuals in 2003. So the population declined by 64% since then. This is due to Black Saturday fire (a large scale bushfire occurred in 2009) which burnt 40-45% of their best habitat (IUCN 2016). Additionally, this population is genetically distinct from the Healesville-Marysville population.

The main population lives in Healesville-Marysville area, which holds about 1,500 individuals. Again, this population number has plummeted. In 1980 population was estimated at 7,500 individuals so the population decreased by 80% since then (Smith 1995; Smith et al 1985; Smith and Lindenmayer 1992). As a result, they are classified as CR in 2014. This decline is due to habitat loss. So now we look at the habitat areas. In 1989 their suitable habitat was estimated at 11,470 ha, but in 2013, only 2,225 ha remained (81% decline). So you can see the connection between habitat and population here.  Both habitat and main population have declined by 81% and 80% respectively since 1980’s.

Great Forest National Park

One way of helping Leadbeater’s Possum is to support Great Forest National Park which is a plan to protect the central highlands of Victoria. Visit the website. It tells you about the project far better than me. It is a great idea anyway.

Over thousands of years, nature has provided the resources that have helped us to survive and flourish. Now, in a time of need, we must help nature to survive. The Great Forest National Park is a project to secure the future of a threatened ecosystem. If we act now, we will be ensuring the forest can continue to provide services that support us- clean water, fresh air and storage of carbon. If we fail now, what future will we have chosen for our grandchildren and their grandchildren?  Please join me in supporting the creation of the Great Forest National Park.

Dr Jane Goodall (quotation from Great Forest National Park website)

The maintenance of an intact ecological system is the only way to ensure the continued existence of biodiversity, safeguard water supplies and provide spiritual nourishment for ourselves and future generations. It is for these reasons, and for the survival of the critically endangered Leadbeater’s Possum, that I support the creation of the Great Forest National Park for Victoria.

Sir David Attenborough (quotation from Great Forest National Park website)

Donation

Visit Friends of Leadbeater’s Possum website’s donation page. You can make a donation as small as AU$10.

Or visit Australian National University’s Victorian Central Highlands Research Fund page. You can donate online there.

References

  • Smith, A. P., (1984). Demographic consequence of reproduction, dispersal, and social interaction in a population of Leadbeater’s Possum. Pp. 359-73 in Possums and Gliders, eds A.P Smith and I. D. Hume, Surrey Beatty & Sons, (Sydney).
  • Smith, A. P. & Lindenmayer, D. B., (1992). Forest succession and habitat management for Leadbeater’s Possum in the state of Victoria, Australia. In Forest Ecology and Management. 49, 311-32.
  • International Union for Conservation of Nature. (2016). The IUCN Red List for Threatened Species.
  • Smith, A. P., (1995). The Natural History of Leadbeater’s Possum. In Leadbeater’s Possum. Edited by Myroniuk P. O. Zoological Board of Victoria, (Parkville).
  • Lindenmayer, D. B., (1995).  The distribution, nest tree and habitat requirements of Leadbeater’s Possum. In Leadbeater’s Possum. Edited by Myroniuk P. O. Zoological Board of Victoria, (Parkville).
  • Hall, L. S., (1974). A recent bone deposit at Marble Arch, NSW. Proceedings 10th Biannual Conference, Australian Speleological Federation, pp. 35-46.
  • Flood, J. M., (1974). Pleistocene man at Cloggs Cave – his tool kit and environment. In Mankind 9, 175-88.
  • Broom, R., (1895a). Report on a bone breccia deposit near the Wombeyan Caves NSW, with description of some new species of marsupials. In Proceedings of the Linnaean Society of NSW 10, 48-61.
  • Broom, R., (1895b). On a small fossil marsupial with large grooved pre-molars. In Proceedings of the Linnaean Society of NSW. 10, 562-67.
  • Broom, R., (1896). On a small fossil Petaurus-like marsupial. In Proceedings of the Linnaean Society of NSW. 10, 568-70.
  • Wakefield, N. A., (1972). Paleoecology of fossil mammal assemblages from some Australian caves. In Proceedings of the Royal Society of Victoria 85, 1-26.
  • Wakefield, N. A., (1967). Mammal bones in the Buchan district. In Victorian Naturalist 84, 211-14.
  • Wilkinson, H. E., (1961). The rediscovery of Leadbeater’s Possum, Gymnobelideus leadbeateri McCoy. In Victorian Naturalist 78, 97-102.
  • Thomas, V. C., (1989). The ecology of Leadbeater’s Possum in the Cockatoo Swamp, Yellingbo State Nature Researve. BSc (Hons) thesis, La Trobe University, Melbourne.
  • Lindenmayer, D. B., Smith, A. P., Craig, S. A., & Lumsden, L. F., (1989). A survey of the distribution of Leadbeater’s Possum, Gymnobelideus leadbeateri, in the Central Highlands of Victoria. In Victorian Naturalist. 106, 174-78.
  • Smith, A. P. & Lindenmayer, D. B., (1988). Tree hollow requirement of Leadbeater’s Possum and other Possums and gliders in timber production forests of the Victorian Central Highlands. In Australian Wildlife Research. 15, 347-62
  • Lindenmayer, D. B., Cunningham, R. B., Tanton, M. T., Smith, A. P., & Nix, H. A., (1991). Characteristics of hollow-bearing trees occupied by arboreal marsupials in the montane ash forests of the Central Highlands of Victoria, south eastern Australia. In Forest Ecology and Management. 40, 289-308.