The Forrest's mouse (Leggadina forresti), or desert short-tailed mouse, is a small species of rodent in the family Muridae. It is a widespread but sparsely distributed species found across arid and semi-arid inland Australia, commonly found in tussock grassland, chenopod shrubland, and mulga or savannah woodlands.
Description
The Forrest's mouse is a small mouse weighing between 15 and 25 grams (0.53 and 0.88 oz),[2] but recorded to 30 grams (1.1 oz).[3] Short, thick tail that is distinctly less than (60–70%) of the combined head and body length.[2][4] Body is thickset with a broad, blunt muzzle,[2] and relatively small ears and eyes.[4] Upperparts are a thick, lustrous and short fur of pale yellow brown or greyish fawn, with a pencilling of darker hairs, and small white patches behind the ears.[2][4] There is a strong demarcation to white under the lower jaw, chin and feet, with the sparsely haired tail grey above and pale grey below, and the ears rounded and pinkish-grey.[2]
Taxonomy
Oldfield Thomas first identified Leggadina forresti in 1906 from a specimen collected at Alexandria Station in the Northern Territory.[5] The genus Leggadina contains two species, both found in Australia including Leggadina forresti and the tropical short-tailed mouse, or Lakeland Downs mouseLeggadina lakedownensis, which is found in moist tussock grassland and tropical savannah of coastal northern Australia.[2]
The species was previously listed as Lower Risk/near threatened in 1996 on the IUCN Red List of Threatened Species, but was reassessed in 2008 as a species of least concern.[1] The Forrest's mouse is not listed under the Australian Environment Protection and Biodiversity Conservation Act 1999, but is listed as Vulnerable in NSW on Schedule 2 of the Threatened Species Conservation Act 1995.
Ecology and habitat
Example of habitat of the Forrest's mouse
A nocturnal and terrestrial animal, the Forrest's mouse shelters during the day in a grass nest in shallow burrows (possibly at the base of spinifex tussocks), and also in cracks in the soil.[2][4]
Although little is known on the population dynamics and social organisation of the species, it is thought they are a solitary animal, occurring in low densities regardless of habitat suitability.[5] Individuals have been recorded entering a state of torpor in both captivity and the wild, and longevity is estimated to be 1.5 to 2 years.[7]
Habitats are varied and include: riparian Coolabah forest, tussock grassland, stony saltbush plains, mulga and savannah woodlands, chenopod shrubland and sandy ridges,[4] and cracking clay pans.[8]
Reproduction
The reproductive rate of Forrest's mouse peaks during winter and spring, with some breeding occurring in autumn,[7] and thought to be related to rainfall.[2] Litter size is usually of three to four young, with a gestation period of 35 days, and a weaning period of 28 days,[9] when the young reach around 9 grams (0.32 oz) in weight.[5] It is unclear as to the age at which individuals reach sexual maturity.[7]
Diet
The Forrest's mouse has a varied diet, and is considered an omnivore. Food items identified include seeds, green plant stems and leaves, arthropods including beetles and spiders, and fungi.[2][7][10] Assessment of stomach contents concluded the major food item was seed (47%), followed by arthropods at 27%, with the remainder consisting of stem and leaf material.[11] It is generally thought that the Forrest's mouse does not rely on standing water for drinking, as it obtains sufficient moisture from its diet in a similar fashion to other well adapted desert rodents.[7]
Predators
The Forrest's mouse is subject to predation by both introduced animals and native predators. Both feral cats Felis catus and the European red fox Vulpes vulpes have been recorded as preying on the Forrest's mouse in Queensland,[12] which has been identified as a contributing factor in the decline of native rodents.[7] The barn owlTyto alba is known to prey on the species in South Australia,[13] and other birds of prey recorded consuming the Forrest's mouse include the letter-winged kiteElanus scriptus in the Simpson Desert.[14] In assessing the risk of dingoCanis lupus dingo predation to threatened vertebrates in western NSW after re-introduction, it was found that the Forrest's mouse faced a high risk of predation from dingoes, based on bodyweight, behaviour and habitat.[15]
Threats
Heavy grazing and the trampling of habitat by domestic stock, feral goats, rabbits and pigs has been identified as a threat to the Forrest's mouse.[4] Grazing by stock affects native rodents through the removal of shrubs and grasses that provide food and shelter, and powder and compact the topsoil, which makes burrowing difficult or impossible.[7] This can also make the Forrest's mouse more vulnerable to predation, and reduces the ability to move between isolated habitats.[4]
Predation by feral cats and foxes is considered a threat to the Forrest's mouse, and exotic species such as the house mouseMus domesticus have the ability to sustain the population of predators.[7] The house mouse, along with other introduced herbivores compete with the Forrest's mouse for food resources and habitat.[4]
The loss of habitat through inappropriate or altered fire regimes is recognised as a threatening process for native rodents, however it is unclear as to whether the Forrest's mouse is adversely affected by current fire regimes, or what requirements are needed in terms of fire history.[7]
The use of 1080 poison(sodium monofluoroacetate) in pest control has the potential to poison the Forrest's mouse through the ingestion of baits,[4][7] and the use of pesticides for the control of locusts may also represent a threat.[7]
The introduction of standing water through farm dams and irrigation schemes has the potential to attract potential predators and competitors of the Forrest's mouse,[4] and serve as focal point for herbivores and the modification of vegetation through grazing.[7]
A loss of habitat through the clearing of trees, shrubs and grasses, the removal of ground debris and loss of hollows have also been identified as a threat to the survival of the Forrest's mouse.[4]
^ abcdefghijMenkhorst, P., and Knight, F. (2001). A field Guide to the Mammals of Australia. Oxford University Press South Melbourne, p.184 ISBN0-19-550870-X
^Breed, W. G.; Taylor, J. (2000). "Body mass, testes mass, and sperm size in Murine rodents". Journal of Mammalogy. 81 (3): 758–768. doi:10.1093/jmammal/81.3.758.
^Reid, J. R. W. (2008). Central Short-tailed Mouse, Leggadina forresti. In Van Dyck, S., and Strahan, R. (eds). The Mammals of Australia. Third Edition. Reed New Holland, Sydney, Australia, pp. 581–583.
^Murray, B. R.; Dickman, C. R.; Watts, C. H. S.; Morton, S. R. (1998). "The dietary ecology of Australian desert rodents". Wildlife Research. 26: 857–858. doi:10.1071/wr97046_co.
^Read, D. G. (1984). "Diet and habitat preference of Leggadina forresti (Rodentia: Muridae) in Western New South Wales". Australian Mammalogy. 7 (4): 215–217. doi:10.1071/AM84023. S2CID254718645. In NPWS. (2002). Forrest's Mouse (Leggadina forresti) and Sandy Inland Mouse (Pseudomys hermannsburgensis) Recovery Plan. NSW National Parks and Wildlife Service, Hurstville, NSW. http://www.environment.nsw.gov.au/resources/nature/approvedSandyforest.pdf
^McDowell, M. C.; Medlin, G. C. (2009). "The effects of prey selection of the barn owl (Tyto alba) in the Strzelecki Regional Reserve, north-eastern South Australia". Australian Mammalogy. 31: 47–55. doi:10.1071/am08115.
^Allen, B. L.; Fleming, P. J. S. (2012). "Reintroducing the dingo: the risk of predation to threatened vertebrates of western New South Wales". Wildlife Research. 39: 35–50. doi:10.1071/WR11128. S2CID83937657.
