When ancestry haunts – can evolutionary links to ancestors affect vulnerability of Australian prey to introduced predators? A preliminary study

The high extinction risk of Australian marsupials has been attributed to their failure to recognise novel predators, the application of inappropriate antipredator responses, and advanced hunting strategies of novel predators. This study is a preliminary attempt to explore whether the Lumholtz’ tree-kangaroo (Dendrolagus lumholtzi) (a) is able to recognise odour cues from different predators as threats, and (b) possesses predator-archetype specific antipredator responses. A small number of available captive tree-kangaroos were exposed to faecal odours from two extant predators of different archetypes (python, dingo), a regionally extinct predator which closely matches past terrestrial predators (Tasmanian devil), and a novel predator (domestic dog). Lavender oil was used as non-predator novel odour and water as control. Results suggest that all subjects associated the presented odours with a threat, albeit to different degrees, but did not display predator-archetype specific responses. It appears that this species applies an ancestral antipredator response of flight-on-the ground when encountering predators, including novel predators. Although the results need to be confirmed with more animals, further studies on the vulnerability of Australian prey to novel predators should take the ancestral history of Australian prey species into account.

Patterns and composition of medium and large vertebrate roadkill, based on six annual surveys along two adjoining highways in south-eastern Queensland, Australia

Six annual single-pass roadkill surveys along two adjoining rural Queensland highways near Carnarvon Gorge National Park revealed 612 medium-size to large vertebrates, representing more than 18 taxa. Most were mammals (92%), particularly macropods. Losses averaged 0.26 animals km–1 year–1 (range = 0.17–0.33), with variation possibly reflecting road repair/reconstruction and record seasonal rainfalls. Annual roadkill totals for the 390-km highway were projected to be over 5000 vertebrates, with more than half being large macropods. A consistent hotspot or ecological trap was noted along a 17-km high-traffic-volume stretch north of Roma. Because the sparsely populated outback is habitat for much Australian wildlife, multiyear baseline data are vital to identify the magnitude of the problem and inform future research.