Sandhill dunnart

The sandhill dunnart is commonly known as a species of "marsupial mouse". The genus name of dunnart was likely derived from the Noongar word "danard". It is the second largest of the 19 dunnart (Sminthopsis) species, with an adult body mass of up to for females and for males. suggest that it is basal to its genus. The sandhill dunnart usually moves by running smoothly on all four legs, sometimes with sudden short stops, during which they often squat with the forebody slightly elevated. The maximum speed recorded for S. psammophila is . ==Ecology==

Diet The species prefers to eat invertebrate prey, such as ants, beetles, spiders, grasshoppers, termites, wasps and centipedes. In the Western Great Victoria Desert, the sandhill dunnart has an ant-rich diet, commonly consuming Camponotus spp. (sugar ants) and Iridomyrmex spp. (meat ants). Physiology In severe conditions when food is scarce, the sandhill dunnart enters short and shallow periods of torpor. The species' documented states of mental and physical inactivity helps it to conserve water and energy. Sexual maturity for both the male and female dunnart is reached by one year of age. Behaviour Sandhill dunarts are typically solitary and nocturnal, emerging shortly after dusk and foraging almost continuously until dawn. Populations have naturally low densities but can increase significantly following major rainfall events. Individuals exhibit both "resident" or highly mobile "transient" behaviour to locate resource patches when they become available. ==Distribution==

The sandhill dunnart currently inhabits sandy, semi-arid regions dominated by spinifex (Triodia) grasslands in South Australia and Western Australia. However, the type specimen was caught "with a thrown boot" during the Horn Expedition in 1894 in the Northern Territory. Subsequently, it was recorded in owl pellets only in Uluru's caves. Shortly after, the sandhill dunnart was mistakenly presumed extinct. In 1969, the sandhill dunnart was detected on Eyre Peninsula in South Australia. Eyre Peninsula is a well-studied stronghold. Records have been radiocarbon dated to approximately 2-3 thousand years ago. From the 1990s, the Yellabinna Regional Reserve in South Australia was confirmed as a second stronghold. From 2017, several S. psammophila records were confirmed between the Eyre Peninsula and Yellabinna populations. The third stronghold is the Western Australian Great Victoria Desert. Individuals were detected near Mulga Rockhole in 1985 and later in/near Queen Victoria Spring Nature Reserve and near Tropicana Gold Mine. In 2018, another population was detected 150 km north of the known range. Ancient sandhill dunnart bones have been recorded by Dr Alex Baynes near Yalgoo and Lake Barlee (400-600 km west of the current population), indicating that the sandhill dunnart was once more widespread in Western Australia. Each stronghold is genetically differentiated, based on the frequency of microsatellite alleles and CR haplotypes, and should be considered as distinct Management Units for conservation. Yellabinna and Western Australian populations share a mtDNA haplotype, indicating historical connectivity across the southern Great Victoria Desert. No significant genetic structure or sex-biased dispersal was detected locally, suggesting that both sexes are highly mobile. Individuals can therefore relocate to neighbouring resource patches when available. Although previously more widespread, the sandhill dunnart has experienced a significant range contraction. The sandhill dunnart may continue to contract south in the future because of the effects of climate change. Due to the cessation of suitable spinifex habitats in the south, the Great Victoria Desert populations are at risk of extinction by 2070. == Habitat ==

Sandhill dunnarts are nocturnal and typically dig burrows to shelter from the climatic extremes of the day. Hence, the population density of the sandhill dunnart is difficult to estimate. ==Threats==

The decline of the sandhill dunnart is likely due to a combination of factors. Predation by introduced species such as the red fox and feral cat, habitat degradation by livestock grazing, land clearance (e.g., in Eyre Peninsula where only 43 % of the original vegetation remains Wildfires are a major threat to the sandhill dunnart as it requires mature spinifex grassland habitats. However, the sandhill dunnart has been radio tracked to shelters in a range of fire ages, including recently burned habitats. Rapidly increasing temperatures, irregular rainfall patterns and more frequent/extreme events (e.g., wildfires and droughts) are particularly dangerous in Australia. Water is already scarce, vegetation is highly flammable, and the generally flat landscape impedes elevation shifts that allow species to compensate against rising temperatures. Modelling predicts that under RCP 8.5 which is our current greenhouse gas (GHG) emissions pathway, suitable habitat for S. psammophila may reduce by 95% in Western Australia by 2050. By 2070, only the Eyre Peninsula population may remain viable and the continental distribution of S. psammophila may contract by up to 80%. However, this contraction could be halved if emissions peak in 2040 then reduce (RCP 4.5). == Conservation ==

Sminthopsis psammophila is listed as 'Endangered' under the Australian Federal EPBC Act (1999). Western Australian populations are listed as 'Endangered' by the Biodiversity Conservation Act (2016) and South Australian populations are listed as 'Vulnerable' by the National Parks and Wildlife Act (1972). The IUCN conservation status has fluctuated from 'Data Deficient' to 'Endangered' and is now classified as 'Vulnerable'. However, the IUCN conservation status of S. psammophila may require review. Translocations to reserves in climatic refuges or to artificial desert ecosystems may be required. Prior to colonisation, sandhill dunnart habitats were managed by the First Australians. Cultural/traditional burning practices promoted landscapes which supported fauna and flora. Globally, two-way science and right-way fire programs have produced results for many threatened species. Hence, Indigenous Protected Areas are key for the conservation of Australian species. Citizen science projects with community groups such as the Friends of the Great Victoria Desert should be also promoted. Most significantly, mitigating the effects of climate change by reducing GHG emissions is vital for the conservation of S. psammophila and many other Australian species. ==References==