Northern hairy-nosed wombat

The northern hairy-nosed wombat (Lasiorhinus krefftii) or yaminon is one of three extant species of wombats. It is one of the rarest land mammals in the world and is critically endangered. Its historical range extended across New South Wales, Victoria, and Queensland as recently as 100 years ago, but it is now restricted to one place, a 3-km2 range within the 32-km2 Epping Forest National Park in Queensland. In 2003, the total population consisted of 113 individuals, including only around 30 breeding females.[3] In the last census taken in 2013, the estimated population was 196 individuals, with an additional 9 individuals at the Richard Underwood Nature Refuge at Yarran Downs near St. George in southern Queensland. In recent years, the population has experienced a slow but steady increase to an estimated 230 individuals in 2015.[4]

Northern hairy-nosed wombat[1]
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Marsupialia
Order: Diprotodontia
Family: Vombatidae
Genus: Lasiorhinus
Species:
L. krefftii
Binomial name
Lasiorhinus krefftii
(Owen, 1873)
Northern hairy-nosed wombat range

Description

In general, all species of wombat are heavily built, with large heads and short, powerful legs. They have strong claws to dig their burrows, where they live much of the time. It usually takes about a day for an individual to dig a burrow.

Northern hairy-nosed wombats have bodies covered in soft, grey fur; the fur on their noses sets them apart from the common wombat. They have longer, more pointed ears and a much broader muzzle than the other two species.[5] Individuals can be 35 cm high, up to 1 m long and weigh up to 40 kg. The species exhibits sexual dimorphism, with females being somewhat larger than males due to the presence of an extra layer of fat. They are slightly larger than the common wombat and able to breed somewhat faster (giving birth to two young every three years on average).

The northern hairy-nosed wombat's nose is very important in its survival because it has very poor eyesight, so it must detect its food in the dark through smell. Examination of the wombat's digestive tract shows that the elastic properties of the ends of their large intestines are capable of turning liquid excrement into cubical scat.[6]

Behaviour

The northern hairy-nosed wombat is nocturnal, living underground in networks of burrows. They avoid coming above ground during harsh weather, as their burrows maintain a constant humidity and temperature.[7] They have been known to share burrows with up to 10 individuals, equally divided by sex. Young are usually born during the wet season, between November and April. When rain is abundant, 50-80% of the females in the population will breed, giving birth to one offspring at a time. Juveniles stay in their mothers' pouches for 8 to 9 months, and are weaned at 12 months of age.[8]

The fat reserves and low metabolic rate of this species permit northern hairy-nosed wombats to go without food for several days when food is scarce. Even when they do feed every day, it is only for 6 hours a day in the winter and 2 hours in the summer, significantly less than a similar-sized kangaroo, which feeds for at least 18 hours a day. Their diet consists of native grasses: black speargrass (Heteropogon contortus), bottle washer grasses (Enneapogon spp.), golden beard grass (Chrysopogon fallax), and three-awned grass(Aristida spp.), as well as various types of roots. The teeth continue to grow beyond the juvenile period, and are worn down by the abrasive grasses they eat.. Its habitat has become infested with African buffel grass, a grass species introduced for cattle grazing. The grass outcompetes the more nutritional and native grasses on which the wombat prefers to feed by limiting its quantity, forcing the wombat to travel further to find the native grasses it prefers, and leading to a reduction in biomass.[9]

Taxonomy

Nomenclature

The genus name Lasiorhinus comes from the Latin words lasios, meaning hairy or shaggy, and rhinus, meaning nose.[10] The widely accepted common name is northern hairy-nosed wombat, based on the historical range of the species, as well as the fur, or "whiskers", on its nose. In some older literature, it is referred to as the Queensland hairy-nosed wombat.[11]

Classification

The northern hairy-nosed wombat shares its genus with one other extant species, the southern hairy-nosed wombat, while the common wombat is in the genus Vombatus. Both Lasiorhinus species differ morphologically from the common wombat by their silkier fur, broader hairy noses, and longer ears.[12]

The koala is the most closely related marsupial to wombats, and is categorised in the same suborder, Vombatiformes.[13]

Conservation

Threats to the northern hairy-nosed wombat include small population size, predation, competition for food, disease, floods, droughts, wildfires, and habitat loss. Its small, highly localised population makes the species especially vulnerable to natural disasters. Originally there were two main groups of hairy-nosed wombats (Lasiorhinus latifrons) that were separated by Spencer Gulf in Australia, both species experienced a population decline between 1870 and 1920, with the main influences of competition for food, competition, and predation.[14] Wild dogs are the wombat's primary predator. As well, rabbits and the actions of land owners have contributed to the decline of these wombats. The necessity to control rabbits through methods that do not harm wombats can combat wombat decline.[15] The habitat at Epping Forest National Park is now well-protected for better chances of survival.

Due to these threats, the northern hairy-nosed wombat is listed as "endangered" by the Australian Species Profile and Threats Database (SPRAT),[16] and "critically endangered" by the IUCN.[2] Its range is restricted to about 300 ha (750 acres) of the Epping National Forest in east-central Queensland, 120 km northwest of Clermont.

In 2003, researchers performed a study to analyse the demography of the northern hairy-nosed wombat. In the study, researchers used double-sided tape in the burrows to collect hair of the wombats. Through DNA analysis, they found that the ratio of female to male NHN wombats was 0.308 out of 113 wombats. These findings allowed researchers to understand the demographics of the NHN wombat and opened up further research to better understand why there is a significant difference in males and females in the wild.[17]

There have been two reports of male northern hairy-nosed wombats contracting a fungal infection caused by Emmonsia parva, a soil saprophytic fungus. It is likely that the northern hairy-nosed wombats are inhaling the infection from the soil. These 2 case studies provide insightful new information on how we can prevent further deaths.[18]

To combat the vulnerability of this species, a number of conservation projects have been put into action over recent years. One example was the construction of a two-metre-high, predator-proof fence around 25 km2 of the park in 2000. A second, insurance colony of this species of wombat has been established at Richard Underwood Nature Refuge at Yarran Downs near St. George in southern Queensland.[19] This second population was established in 2008 and is also in a reserve surrounded by a predator-proof fence.[19] Within Epping Forest National Park, increased attention and funds have been given for wombat research and population monitoring, fire management, maintenance of the predator-proof fence, general management, and control of predators and competitors, and elimination of invasive plant species.[20] In addition, the species recovery plan of 2004 to 2008 included communication and community involvement in saving the species and worked to increase the current population in the wild, established other populations within the wombat's historical range, and worked with zoos to establish a captive husbandry program. Also, a volunteer caretaker program allows volunteers to contribute in monitoring the population and keeping the predator fence in good repair. Finally, DNA fingerprint identification of wombat hairs allows research to be conducted without an invasive trapping or radio-tracking program.[21] Due to the combined efforts of these forces, the northern hairy-nosed wombat population is slowly making a comeback.[22]

References
  1. Groves, C. P. (2005). "Order Diprotodontia". In Wilson, D. E.; Reeder, D. M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 43. ISBN 978-0-8018-8221-0. OCLC 62265494.
  2. Taggart, D.; Martin, R. & Horsup (2008). "Lasiorhinus krefftii". IUCN Red List of Threatened Species. 2008. Retrieved 2 September 2009.CS1 maint: ref=harv (link)
  3. Eastwood, K. (October–December 2003). "Saving the northern hairy-nosed wombat". Australian Geographic (72).
  4. Horsup, Alan (23 October 2015). "Northern hairy-nosed wombat". Queensland Government. The State of Queensland (Department of Environment and Heritage Protection). Retrieved 30 August 2016.
  5. Jew, Darren. "Northern Hairy-Nosed Wombat". Wildlife Preservation Society of Qld. Wildlife Queensland. Retrieved 23 February 2014.
  6. Akst, Jef. “Image of the Day Wombat Poop.” https://www.the-scientist.com/image-of-the-day/image-of-the-day--wombat-poop-65115
  7. Banks, Sam; Hoyle, Horsup; Sunnucks, Taylor (28 February 2006). "Demographic monitoring of an entire species (the northern hairy-nosed wombat, Lasiorhinus krefftii) by genetic analysis of non-invasively collected material". Animal Conservation. 6 (2): 101–107. doi:10.1017/S1367943003003135.
  8. Johnson, C. N.; Crossman (23 March 2009). "Dispersal and social organization of the northern hairy-nosed wombat Lasiorhinus krefftii". Journal of Zoology. 225 (4): 605–613. doi:10.1111/j.1469-7998.1991.tb04328.x.
  9. "Department of the Environment and Energy". Department of the Environment and Energy. Retrieved 2 May 2018.
  10. Gotch, A. F. (1979). Mammals, their Latin names explained. Poole: Blanchford Press.
  11. Gordon, G.; Riney, T.; Toop, J.; Lawrie, B.C.; Godwin, M.D. (1985). "Observations on the Queensland Hairy-nosed Wombat, Lasiorhinus krefftii (Owen)". Biological Conservation. 33 (2): 165–195. doi:10.1016/0006-3207(85)90102-8.
  12. Horsup, A. "Recovery plan for the northern hairy-nosed wombat Lasiorhinus krefftii 2004-2008". Report to the Department of Environment and Heritage, Canberra. Retrieved 12 April 2019.
  13. Triggs, B (2009). Wombats. Collingwood, Australia: CSIRO Publishing.
  14. Swinbourne, Michael J., et al. “Historical Changes in the Distribution of Hairy-Nosed Wombats (Lasiorhinus Spp.): a Review.” Australian Mammalogy, vol. 39, no. 1, 2017, p. 1., doi:10.1071/am15046.
  15. Ostendorf, Bertram; Peacock, David; Taggart, David A.; Swinbourne, Michael J. (4 April 2017). "Historical changes in the distribution of hairy-nosed wombats (Lasiorhinus spp.): a review". Australian Mammalogy. 39 (1): 1–16. doi:10.1071/AM15046. ISSN 1836-7402.
  16. "Lasiorhinus krefftii Northern Hairy-nosed Wombat". deh.gov.au. Retrieved 5 January 2007.
  17. Banks, Sam C.; Hoyle, Simon D.; Horsup, Alan; Sunnucks, Paul; Taylor, Andrea C. (13 June 2002). "Demographic monitoring of an entire species (the northern hairy-nosed wombat, Lasiorhinus krefftii) by genetic analysisof non-invasively collected material". Animal Conservation. 6 (2): 101–107. doi:10.1017/S1367943003003135.
  18. Schaffer‐White, A. B.; Harper, D.; Mayhew, M.; McKinnon, A.; Knott, L.; Allavena, R. E. (2017). "Pulmonary adiaspiromycosis in critically endangered northern hairy-nosed wombats (Lasiorhinus krefftii)". Australian Veterinary Journal. 95 (11): 431–436. doi:10.1111/avj.12642. ISSN 1751-0813. PMID 29076222.
  19. Department of Environment and Resource Management. "Northern hairy-nosed wombat". Queensland Government. Archived from the original on 6 June 2012. Retrieved 28 January 2011.
  20. Short, Jeff; Smith (2 May 1994). "Mammal Decline and Recovery in Australia". Journal of Mammalogy. 75 (2): 288–301. doi:10.2307/1382547. JSTOR 1382547.
  21. White, Lauren C.; Horsup, Alan; Taylor, Andrea C.; Austin, Jeremy J. (2014). "Improving genetic monitoring of the northern hairy-nosed wombat (Lasiorhinus krefftii)". Australian Journal of Zoology. 62 (3): 246–250. doi:10.1071/zo14031. S2CID 84706304.
  22. Sloane, M. A.; Sunnucks, Alpers; Taylor, Beheragary (September 2000). "Highly reliable genetic identification of individual northern hairy-nosed wombats from single remotely collected hairs: a feasible censusing method". Molecular Ecology. 9 (9): 1233–1240. doi:10.1046/j.1365-294x.2000.00993.x. PMID 10972763. S2CID 23163044.
  • Underhill D (1993). Australia's Dangerous Creatures. Sydney NSW: Reader's Digest. ISBN 978-0-86438-018-0.
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