Lee, E, Klöcker, U, Croft, DB & Ramp, D 2004, 'Kangaroo-vehicle collisions in Australia's sheep rangelands, during and following drought periods.', Australian Mammalogy, vol. 26, no. 2, pp. 215-215.
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The effects of roads on wildlife behaviour and ecological function are poorly known in aridAustralia. The most obvious impact is roadkill from wildlife-vehicle collisions. Therefore wecollected statistics on kangaroo-vehicle collisions, investigated the causal factors of thesecollisions, and related roadkill mortality to the population structure, size and distribution of fourkangaroo species in two intensive six month studies during and following drought. Theresearch was conducted along a 21.2 km sealed section of the Silver City Highway betweenBroken Hill and Tibooburra that passes through the University of New South Wales (NSW)Arid Zone Research Station at ‘Fowlers Gap’ in north-western NSW. The rate of roadkill washigher during drought (20.8 roadkills month-1) than non-drought (2.6 roadkills month-1).Affected species were red kangaroos (Macropus rufus), euros (Macropus robustus erubescens),western grey kangaroos (Macropus fuliginosus) and eastern grey kangaroos (Macropusgiganteus). During drought, M. fuliginosus and M. giganteus were killed in lower proportionsthan their proportion in the source population, otherwise species were killed in proportion totheir density along the road. There were no sex biases but male M. r. erubescens were muchmore likely to be beside the road than females and thus were killed more often during drought.The majority of roadkills were young individuals around 2 years old. Curves and stockracesalong the road significantly increased the likelihood of roadkills. Likewise the frequency ofroadkills was a function of the kangaroo population density along the road, night time trafficvolume, low rainfall and higher vegetation cover and greenness along the road relative tosurrounding areas. We evaluate the relationships between these causal factors and kangaroovehiclecollisions, and discuss the possible effects of these collisions on kangaroo populationstructure under drought and post-drought conditions.
Ramp, D & Coulson, G 2004, 'Small-scale patch selection and consumer-resource dynamics of eastern grey kangaroos', JOURNAL OF MAMMALOGY, vol. 85, no. 6, pp. 1053-1059.
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Models of kangaroo populations have primarily focused on the prediction of population growth and distribution in relation to environmental variation at broad geographic scales. Current understanding of small-scale patterns in distribution, habitat breadth, and niche occupation is less complete. A powerful model of dispersion is ideal free distribution (IFD) theory. In plant-herbivore grazing systems, the most appropriate IFD models are those that allow for the incorporation of a standing crop of resources. Using eastern grey kangaroos (Macropus giganteus), we test the predictions of a previously described standing-crop IFD model where the number of consumers on a patch is proportional to the resource input rate, the standing crop of resources on all patches at equilibrium are equal (in the absence of interference), and the resource mortality rate is directly equivalent to the resource input rate, and is independent of the resource density (in the absence of interference). We make these comparisons at both the habitat and patch scale. At the habitat scale, we observed significant departures from these predictions that are consistent with the commonly reported occurrence of undermatching, whereas at the patch scale, little concordance with the predictions was observed. These results suggest that eastern grey kangaroos select for resources at the habitat scale but not at the level of the patch.
