Oral Presentation- Symposium 12th International Mammalogical Congress

The diversity of carnivorous marsupials (Dasyuridae) in the Australian arid zone (#247)

Chris R Pavey 1 , Gerhard Koertner 2 , Fritz Geiser 2
  1. Land and Water, CSIRO, Darwin, Northern Territory, Australia
  2. Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales, Australia

Arid Australia supports a high diversity of carnivorous marsupials (Dasyuridae) with about half of the Australian species living entirely or partially in the arid zone. This environment is dominated by long periods with low resource availability and daily extremes in temperature. Here we examine patterns of occurrence and mechanisms of persistence of dasyurids with a particular focus on a 10-year study in the western Simpson Desert. The study area supported an assemblage of 10 species. Population dynamics varied across species, but two species showed a pattern of capture that is analogous to population irruptions of sympatric rodents. These two species, the kultarr (Antechinomys laniger) and fat-tailed dunnart (Sminthopsis crassicaudata) had within-site capture rates as high as 31% (31 animals per 100 trap-nights) during peaks of abundance. All dasyurids used torpor. A detailed study of torpor patterns in the two larger species, brush-tailed mulgara (Dasycercus blythi) and crest-tailed mulgara (D. cristicauda) showed that torpor use was frequent and bouts of torpor were long during winter. However, torpor did not seem to be employed as an immediate response to energy shortage, rather it was tied to reproduction. Both mulgara species captured a broad prey base that included vertebrates, invertebrates and plants. Diets were dominated by invertebrates less than 2 g in body mass. These findings indicate that torpor ensures reproductive success and ongoing persistence in arid carnivorous marsupials and it enables species inhabiting environments with high resource variation (e.g. gibber plain) to exploit peaks in prey availability.