The wonderful world of the wombat

Wombats are native Australian marsupials. There are three species – the northern hairy-nosed wombat (Lasiorhinus krefftii), southern hairy-nosed wombat (Lasiorhinus latifrons) and bare-nosed wombat (Vombatus ursinus). They are important ecological engineers as their burrowing supports aeration and turnover of the soil and provides shelter for other species.

Interestingly, wombats have continuously growing teeth, needed to breakdown the tough vegetation they consume. As herbivores, the diet of wombats consists mostly of grasses, but also sedges and flowering plants. Non-invasive DNA metabarcoding studies have found that bare-nosed wombats eat more than 200 plant species, and the northern hairy-nosed wombat mostly consumes buffel grass, an invasive grass that is outcompeting native grasses in their habitats. Diets also differ seasonally and at different locations where the wombats live but is largely thought to vary based on forage availability.

Wombats are however under threat on many fronts. Since European settlement, land clearing, changed fire regimes, introduced pests, increased urbanisation and subsequently roadkill, as well as disease have reduced wombat numbers.

The most at-risk species of wombat is the northern hairy-nosed wombat which were reduced in number to around 20 individuals late last century. Luckily, a predator-proof fence established in 2000 reduced the risk to the species from dog attacks, and since that time, the number of individuals has increased.

A second translocation site at Richard Underwood Nature Refuge was established in 2009, and this year a third translocation site at Powrunna State Forest saw the arrival of 15 individuals. Although things seem bright for this species in the short-term, the species remains listed as critically endangered by the International Union for the Conservation of Nature (IUCN) Red List.

In contrast, the bare-nosed wombat is listed as least concern on IUCN Red List with two of the biggest threats to this species identified as roadkill and sarcoptic mange.

Roadkill is a major threat for wombats because they traverse roads to find food, mates, and suitable habitat. Citizen science data collected on wombat roadkill has shown an average of 478 wombats are killed per year. Wombat roadkill occurs more in winter and early-spring, when day length is relatively short. NSW and VIC have a higher number of wombats killed on roads compared to the ACT and TAS.

Sarcoptic mange is a terminal disease in wombats if they are not treated, and in humans is called scabies. It is caused by a parasitic mite called Sarcoptes scabiei, which burrows into the skin and causes itching, hair loss, and in the longer term, the skin will be exposed to infection and the wombat will die from those secondary infections if not treated.

A wombat being treated for sarcoptic mange.

Wombats are also easily stressed and do not cope well in captivity, so treating wombats with sarcoptic mange as non-invasively as possible in the field is best. However, treating free-living wombats in the field is problematic because wombats frequent more than one burrow, have large home ranges, are large and not easily handled, and nocturnal.

The WomSAT (Wombat Survey and Analysis Tool) is a national citizen science project with more than 23,000 sightings submitted by citizen scientists, that records observations of wombats and their burrows in real-time.

The information is being used to map the distribution of wombats and to better understand their biology. It is also being used to map roadkill hotspots to identify locations best suited to the introduction of mitigation strategies and to record observations of wombats with sarcoptic mange to better understand the disease and how it varies in different locations and seasons.

WomSAT has recently been upgraded to allow wombat carers to track sarcoptic mange in the field, which will assist in determining the best methods to use to treat wombats in the field and for carers to track their progress.

A new training program has also been developed in close consultation with the Wombat Protection Society of Australia Incorporated. The training program is supported by the NSW National Parks and Wildlife Services Curb Wombat Mange Program and the Foundation for National Parks and aims to improve wombat conservation through safely and effectively curbing mange through increased education.

Ultimately the training will provide wildlife carers with accreditation and approval to treat wombats in the field and improve the outcomes for wombats. The course also provides an opportunity for more people to get involved in wombat conservation. The link for the course is available on the WomSAT website.

This article was written by Associate Professor Julie Old and Dr Hayley Stannard, a Senior Lecturer in Animal Anatomy and Physiology at Charles Sturt University. Funding for the training programme was provided by NSW NPWS Curb Mange Program and the Foundation for National Parks via The Wombat Protection Society of Australia. Photos courtesy of Marie Wynan of the Wombat Protection Society.