Ecology and conservation status of the northern spot-tailed quoll, Dasyurus maculatus with reference to the future of Australia's marsupial carnivores

Burnett, Scott Edward (2001) Ecology and conservation status of the northern spot-tailed quoll, Dasyurus maculatus with reference to the future of Australia's marsupial carnivores. PhD thesis, James Cook University.

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Abstract

The Spot-tailed quoll Dasyurus maculatus is a member of the carnivorous marsupial family, Dasyuridae, and is the largest marsupial carnivore on the Australian mainland. D. maculatus occurs in Tasmania and along the eastern seaboard of Australia as far north as south-east Queensland with a disjunct population in the Wet Tropics World Heritage Area in north Queensland.

Despite being one of the very first Australian mammals to be encountered by Europeans, the ecology of D. maculatus is very poorly known. This dearth of knowledge is worrying given the documented reduction in its geographic range and its listing as threatened or endangered in all mainland states in which it occurs. This study was thus undertaken with the intention of (a), documenting the species' ecology and (b),using this data to elucidate the reasons behind its endangered status and to chart a course for the species recovery.

Fieldwork was conducted between 1992 and 1994 inclusive, solely within the Wet Tropics Area of north Queensland. However, the results are relevant throughout the species' range. The ecology of D. maculatus was studied using capture-mark-recapture, radio-telemetry, mapping of latrine sites, scat analysis and quantification of the prey community. The distribution and abundance of the species within north Queensland was documented by accessing sighting records from a range of unpublished sources including Government Departments, local naturalists and from the community at large, and by field survey. The conservation status of the species was assessed by, (a) conducting Population Viability Analysis, (b) noting changes in the species distribution and abundance, (c) identifying weaknesses in the species life-history strategy and, (d) identification of those phylogenetic, behavioural and environmental factors which expose the species to extinction within the short and long term.

Twenty-four female and 26 male D. maculatus were captured a total of 186 times during this study. The species was found to occur at low densities (approx. 1 individual of each sex per 3km2). Mating occurred during the winter months (June- September) and the average litter size was 5.2. No female was known to breed in more than two successive seasons. Spot-tailed quolls specialised on mammalian prey but showed very little preference for any of the available mammalian prey. The species is highly mobile; one male travelled over six kilometres in 24hr and one female travelled 1km in 3hr. Five radio-collared females occupied discrete and non-overlapping home ranges of up to 11km2. Quolls use roads as latrine sites, and densities of scats of up 30 km-1 of road were not uncommon. Historically, D. maculatus was found throughout the latitudinal range of the Wet Tropics area, however, it appears to have become extinct in the southern Wet Tropics in the 1940' s. It is currently known from eight isolated populations on mountaintops or tablelands in the Wet Tropics and is apparently restricted to rainforest above 700m asl. The total population of the species in the Wet Tropics Area is estimated to be less than 1000 individuals.

I propose that the endangerment of D. maculatus throughout its mainland Australian range can be attributed to its life-history strategy and population ecology which render populations susceptible to extinction through relatively low increases of extrinsic mortality, and its behaviour which exposes individual quolls to the agents of extrinsic mortality. The short-term recovery of quoll populations is thus dependent upon reducing that extrinsic mortality. This can be achieved through education, revised wild dog baiting guidelines and in some instances control of Eutherian carnivore populations. Risk analysis shows that Eutherian carnivores can contribute to the extinction of Quoll populations through predation and competition. This effect is further exacerbated by life-history differences between Quolls and Eutherian carnivores which mean that populations of the Eutherians are intrinsically more persistent under conditions of low recruitment or elevated extrinsic mortality, than those of the Spot-tailed Quoll. In the longer term, I suggest that the survival of Quolls, and the radiation of Australian marsupial carnivores in general, is severely threatened by Australia's Eutherian carnivore fauna.

Item ID: 17435
Item Type: Thesis (PhD)
Keywords: spot-tailed quoll, Dasyurus maculatus, species ecology, abundance, distribution, reproduction, life histories, diet, conservation status, threats, pressures, Eutherian carnivores, predation, competition, species recovery, conservation measures, Wet Tropics World Heritage Area, Mount Windsor Tableland
Date Deposited: 22 Jun 2011 22:16
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050211 Wildlife and Habitat Management @ 50%
06 BIOLOGICAL SCIENCES > 0602 Ecology > 060208 Terrestrial Ecology @ 50%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960806 Forest and Woodlands Flora, Fauna and Biodiversity @ 100%
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