Plains Mouse - profile

Indicative distribution

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Key:

known

predicted

The areas shown in pink and/purple are the sub-regions where the species or community is known or predicted to occur. They may not occur thoughout the sub-region but may be restricted to certain areas. ( click here to see geographic restrictions). The information presented in this map is only indicative and may contain errors and omissions.

Scientific name: Pseudomys australis

Conservation status in NSW: Vulnerable

Commonwealth status: Vulnerable

Gazetted date: 21 May 2021

Profile last updated: 24 May 2021

Description

The Plains Rat (Pseudomys australis) is one of the largest rodents still present in the arid zone, with a body mass up to 50 g. It has a stocky build, rounded snout and long ears. It has greyish upperparts, often lustrous in appearance, with paler flanks and cream or white underparts. The tail is also bicoloured- being brown or grey above and white underneath, and can grow to 12 cm in length.

Distribution

The Plains Rat is restricted to the gibber (stone-covered) plains of Lake Eyre Basin in northern South Australia, and is now presumed to be extinct in Queensland and NSW. The previous distribution of this species extended from the western edge of the Nullabor Range, to central Queensland, as well as the inland slopes of the Great Dividing Range to the mouth of the Murray River. In the Northern Territory, it was formerly present only in the extreme south-east region.

Habitat and ecology

The Plains Rat is primarily found in gibber (stone-covered) plains and mid slopes with boulders, small stones and gilgais (water soaks, depressions). In years of very good rainfall, this species occur on adjoining sandy plains. During poor conditions, core refuge areas may occur on low-lying gilgais and watercourses of gibbber plains.
During poor rainfall years, Plains Rat populations are able to survive without drinking, as water is obtained from the metabolism of starches in its food. However drainage depressions and areas of cracking clays are a sometimes a source of water and generally hold a greater concentration of seeds and dry plant matter than most other habitats. The cracks in the soil trap wind-blown material and decrease its likelihood of harvest by other species such as parrots and other birds. It has been suggested that these areas are the most productive areas of stony desert landscapes compared to sodic and unstable sections of gibber that restrict plant growth.
The Plains Rat forages and is most active during the cool night. A major component of the species' diet is seeds along with other plant material, while invertebrates and fungi are a minor component.
The Plains Rat constructs shallow, complex burrows. In this species' primary habitat, burrows/nests are dug into cracks in the gibber. In secondary habitat areas, complex burrow systems are dug in the softer, more friable soils usually found around the base of chenopod shrubs.
Nests are maintained by breeding females. Breeding is not seasonal but appears to be associated with increased availability of food following significant rainfall events. After these conditions deteriorate, populations can collapse and become undetectable as food resources diminish. Litter size is usually three to four (and up to seven) and weaning takes place 28 days after birth.

Threats

The Plains Rat has suffered a significant reduction in total distribution since European colonisation. Habitat degradation, trampling and over grazing by cattle and rabbits is of particular concern. Also, foxes and dingoes are reported to prey on the Plains Rat and may have contributed to the reduction in its distribution. The Letter-winged Kite is also reported to prey on the Plains Rat. The role of these threats is exacerbated during periods of extreme weather and periods of restricted resource availability.
Predation by introduced species, primarily feral cats and foxes
Competition from large feral herbivores.
Competition from rabbits.
Risk of low genetic diversity from range contraction and fragmentation of known populations potentially limiting long-term viability
Limited known Plains Mice populations reducing New South Wales population viability
Inappropriate fire regime.
Insufficient understanding of distribution and factors influencing the species abundance
Disturbance or clearance of critical habitat (where the species occurs) from pastoral or agricultural development (particularly overstocking). Livestock and feral herbivores trample burrows, increase siltation of cracks in clay refuges and deplete available habitat and food resources.
Increased intensity and frequency of droughts, and increased daytime temperature may negatively impact a range of critical food resources (e.g., grass seeds and invertebrates) and habitat suitability (i.e. making surface soils less suitable for burrows).
Lack of understanding of mesopredator interactions particularly between the species and native and introduced predators where cats and foxes are controlled
Black rats may potentially predate on juvenile Plains Mice where populations are established and their ranges overlap (e.g. mesic environments, more so than arid), which may reduce the success of Plains Mouse introductions.

Recovery strategies

A Saving Our Species conservation project is currently being developed for this species and will be available soon. For information on how you can contribute to this species' recovery, see the Activities to assist this species section below.

Activities to assist this species

There is no existing management program for the wild population of this species in the Northern Territory. A national Recovery Plan is currently being drafted by the South Australian Department of Environment and Heritage.
The Alice Springs Desert Park maintains a captive colony and the species is on permanent display in the nocturnal house at the park.