Fat-tailed dunnarts (Sminthopsis crassicaudata) of the Werribee grasslands: a case study of a species in decline

Abstract. Grasslands are among the most endangered ecosystems, with <1% of Victorian grasslands remaining. Extinctions of many grassland fauna species have occurred since European settlement due to loss of suitable habitat, and dramatic range reductions continue for those that still exist. Fat-tailed dunnarts (Sminthopsis crassicaudata) are the only small ground-dwelling marsupial known to persist in Victorian grassland habitats. The last long-term targeted surveys for this species were conducted in Victoria in the 1970s. Incidental findings from more recent short-term targeted and non-targeted surveys in the same area suggest a decline. We performed direct targeted surveys for fat-tailed dunnarts at the 1970s survey site over a 12-month period in 2019 and found no evidence of fat-tailed dunnart presence. The species is classified as Near Threatened in the state and Least Concern internationally. Our work highlights the importance of targeted surveys to assess the stability of this species across Victoria, and the need for collection of long-term data to better identify population declines.