Bennett's Wallaby Macropus Rufogriseus Research Articles

Dietary partitioning of Australia's two marsupial hypercarnivores, the Tasmanian devil and the spotted-tailed quoll, across their shared distributional range.

Australia’s native marsupial fauna has just two primarily flesh-eating ‘hypercarnivores’, the Tasmanian devil (Sarcophilus harrisii) and the spotted-tailed quoll (Dasyurus maculatus) which coexist only on the island of Tasmania. Devil populations are currently declining due to a fatal transmissible cancer. Our aim was to analyse the diet of both species across their range in Tasmania, as a basis for understanding how devil decline might affect the abundance and distribution of quolls through release from competition. We used faecal analysis to describe diets of one or both species at 13 sites across Tasmania. We compared diet composition and breadth between the two species, and tested for geographic patterns in diets related to rainfall and devil population decline. Dietary items were classified into 6 broad categories: large mammals (≥ 7.0kg), medium-sized mammals (0.5–6.9kg), small mammals (< 0.5kg), birds, reptiles and invertebrates. Diet overlap based on prey-size category was high. Quoll diets were broader than devils at all but one site. Devils consumed more large and medium-sized mammals and quolls more small mammals, reptiles and invertebrates. Medium-sized mammals (mainly Tasmanian pademelon Thylogale billardierii), followed by large mammals (mainly Bennett’s wallaby Macropus rufogriseus) and birds, were the most important prey groups for both species. Diet composition varied across sites, suggesting that both species are flexible and opportunistic foragers, but was not related to rainfall for devils. Quolls included more large mammals but fewer small mammals and invertebrates in their diet in the eastern drier parts of Tasmania where devils have declined. This suggests that a competitive release of quolls may have occurred and the substantial decline of devils has provided more food in the large-mammal category for quolls, perhaps as increased scavenging opportunities. The high diet overlap suggests that if resources become limited in areas of high devil density, interspecific competition could occur.

Influence of patch characteristics on browsing of tree seedlings by mammalian herbivores

Summary In south‐eastern Australia, browsing of commercial tree seedlings by mammalian herbivores in plantation forestry incurs a large economic cost to the industry, through its effect on tree survival, growth and form. In the absence of lethal methods to control herbivore populations, appropriate manipulation of vegetation through silvicultural management may reduce browsing but it relies on understanding the feeding responses of the herbivores to such changes. We evaluated the extent to which vegetation patch characteristics affected browsing of pine Pinus radiata seedlings by generalist mammalian herbivores, including red‐bellied pademelons Thylogale billardierii, Bennett's wallaby Macropus rufogriseus rufogriseus and the common brushtail possum Trichosurus vulpecula. In field trials, browsing of pine seedlings was greatest when they were located in patches of high quality, i.e. palatable short vegetation (grass), intermediate in high‐quality tall vegetation (Lomandra longifolia) and least in low‐quality tall vegetation (bracken and shrub). Patch structure also affected browsing: in low‐quality patches pine seedlings were browsed more in short vegetation patches (12–24 cm shorter than the seedling) than in tall vegetation patches (at least as tall as the seedling). This difference was at least partly because herbivores took, on average, 2 weeks longer to locate seedlings in tall than in short vegetation. In trials with captive red‐bellied pademelons and brushtail possums, pine seedlings were browsed similarly in small short grass and soil patches. However, when these patches were large and spatially separated, they were browsed more in short grass than soil patches. Selection at the patch or individual plant level therefore depended on spatial scale and proximity of the patches. Synthesis and applications. The influence of patch characteristics on browsing has the potential to be exploited for the management of browsing damage to commercially important tree seedlings in forestry plantations. Retention of relatively tall vegetation, particularly if it is unpalatable, in areas at risk of heavy browsing, for example by delaying the use of herbicide, may be a useful management strategy for reducing browsing. This needs to be weighed against the potential detrimental competitive effects of neighbouring vegetation on the seedlings.

A re-examination of Dithyridium cynocephali Ransom 1905, a metacestode parasite from the thylacine Thylacinus cynocephalus

Re-examination of Dithyridium cynocephali Ransom 1905, a metacestode parasite from the thylacine Thylacinus cynocephalus, has revealed it to be morphologically indistinguishable from metacestodes of the tapeworm Anoplotaenia dasyuri found in the eastern quoll Dasyurus viverrinus and the spotted-tailed quoll D. maculatus, in Bennett's wallaby Macropus rufogriseus rufogriseus and in the Tasmanian pademelon Thylogale billardierii. The Tasmanian devil Sarcophilus harrisii is the predominant definitive host for A. dasyuri, but the two quoll species can also serve as definitive hosts. It is considered likely that quolls may act as intermediate hosts through the occasional consumption of Tasmanian devil faeces containing infective A. dasyuri eggs. The thylacine may have become infected with A. dasyuri in a similar manner, by engaging in coprophagy in the wild or in captivity.