Demographic variation and range contraction in the northern quoll, Dasyurus hallucatus (MArsupialia : Dasyuridae).

Abstract

Mark-recapture studies of northern quoll (Dasyurus hallucatus) were conducted in lowland savanna in Kakadu National Park during two periods: in 1985-87 when total mammal abundance was high, and in 1989-91 when total mammal abundance was low. Population characteristics from these studies are compared with results from a 1977-79 study in sandstone escarpment country 40 km to the south-east and from studies in a range of habitats on the Mitchell Plateau in the Kimberley. Populations in rocky country are most dense with animals often surviving two or three years. In contrast, populations in savanna are more sparse, with males and females rarely surviving beyond one mating season. While all populations seem to undergo an annual period of stress, it is the savanna populations that seem most vulnerable. An analysis of the distribution of northern quolls shows a 75% recent range reduction, from being widespread over much of northern Australia to six smaller rocky regions. Possible causes of the decline include cattle, cane toads and exotic disease.