Wombat conservation
History
It is thought that the northern hairy-nosed wombat was likely in decline when Europeans settled in Australia, at that time it was probably the least common of all wombat species. Records confirm the species occurred at three known locations, including the Riverina area in southern New South Wales, the Moonie River area in southern Queensland, and the Epping Forest area in central Queensland.
Since Europeans settled Australia, the main reasons for the species rapid decline include:
- the culling and/or destruction of burrows by farmers in southern New South Wales to control spread of rabbits (Swinbourne 2016) and,
- competition for food from introduced grazing animals, such as sheep, cattle and rabbits, particularly during droughts.
By the early 1980s, the northern hairy-nosed wombats in Epping Forest area of central Queensland were the last remaining population. Alarmingly, the population consisted of only 35 wombats, sparking an intensive research and recovery effort.
As the threats to northern hairy-nosed wombats are better understood, management actions continue to be developed and implemented to mitigate threatening processes. Since 2001, significant increases in wombat numbers have indicated recovery efforts are working. Regardless, ongoing work is needed to ensure the species continues to recover, to reduce the impact of existing threats and to identify and address potential new threats.
In recognition of this ongoing requirement, on 15 February 2018, the federal Department of Agriculture, Water and the Environment (DAWE) upgraded the conservation status of the northern hairy-nosed wombat from Endangered to Critically Endangered under the Environment Protection and Biodiversity Conservation Act 1999. In 2021, the status of northern hairy-nosed wombats under the Queensland Nature Conservation Act 1992 also changed to Critically Endangered. These changes occurred as part of a process to align the categories for threatened species in Australia with those used by the International Union for Conservation of Nature’s Red List of Threatened Species.
The Department of Environment, Science and Innovation (DESI) currently manage both northern hairy-nosed wombat populations at Epping Forest National Park (Scientific) and Richard Underwood Nature Refuge.
Threats
Small population size
A major threat to the northern hairy-nosed wombat's survival is its low population size. Small or isolated populations are more susceptible than larger populations to local catastrophes (i.e., flood, fire, or disease), loss of genetic diversity and inbreeding.
Predation
Previous records have shown predation by wild dogs is a considerable threat to the northern hairy-nosed wombat.
Competition for food
Northern hairy-nosed wombat’s main competitor for food, across its current range, is the eastern grey kangaroo.
Disease
Diseases such as toxoplasmosis (found in cat faeces) or mange, are potential threats to the wombats.
Floods
Floods are a potential threat to populations of northern hairy-nosed wombats, due to their ability to inundate burrow systems and destroy food resources.
In January 2008, Epping Forest National Park (Scientific) was isolated by floodwaters that covered most of central Queensland. The Belyando River, which normally flows some 10km to the west of the park, experienced considerable flooding. At the flood's peak, the park was in the middle of a vast inland sea, with water from the river flowing through the western boundary and wrapping around the park. Anxious departmental officers conducted a helicopter inspection during and after the flood. Fortunately, most of the wombat burrows appeared to be on elevated ground, above the water level.
Drought
Drought, such as the six-year long drought in the 1990s, slows the reproductive output of northern hairy-nosed wombats, and reduces body condition and survival rates in the population. A study by Crossman et al. (1994) found 50-75% of breeding females successfully bred when good summer rainfall occurred, whilst only 20% bred during a major drought.
Wildfire
Wildfire is not a direct threat to individual northern hairy-nosed wombats as deep burrows provide protection. However, fire will destroy food resources and may impact particular tree species whose roots provide stability in wombat burrows.
Loss of habitat
The habitat at Epping Forest National Park (Scientific) and Richard Underwood Nature Refuge is well protected. However, loss of habitat more broadly, through tree clearing and habitat alteration, means that there are a limited number of places to establish new populations of northern hairy-nosed wombats in the future.