Suchergebnisse

Context Roads have numerous impacts on wildlife populations, such as forming barriers to movement and isolating them from resources. However, knowledge of how wildlife behave in road-impacted environments is limited. Aims Our aim was to assess the suitability of roadside habitat for the swamp wallaby (Wallabia bicolor). Methods We measured the home range, habitat use and body metrics of swamp wallabies at two roadside locations. The home ranges and fitness of the roadside wallabies were compared with the metrics of swamp wallabies within the adjacent reserve. Key results The roadside wallabies had a preference for canopy cover, but not for other habitat features. The roadside home ranges were stable and relatively small. The nocturnal ranges were considerably smaller and further from the road than were diurnal ranges. Only one wallaby crossed the road during the study, via an underpass. There was a significant positive linear correlation between pes length and bodyweight. Roadside wallabies were significantly heavier than were reserve wallabies. Conclusions Our study suggested that individual wallabies avoid the road, are habituated to the roadside environment and may even benefit from it. At the very least, roadside habitats are adequate for the swamp wallaby. Implications Fencing and road crossings are likely to be beneficial conservation-management measures for swamp wallabies in roadside reserves.

A goal to reduce the frequency of animal–vehicle collisions is motivating extensive research on this topic world-wide. Over the last 30 years, one popular mechanism to warn wildlife of approaching vehicles has been the wildlife warning reflector, manufactured and distributed under the brands Swareflex (Austria) and Strieter-Lite (USA). These reflectors were designed to scare deer and other ungulates from roadways at night by reflecting light from the headlights of approaching vehicles into the eyes of animals on the road verge. Robust documentation of their effectiveness has been lacking, yet there has been a push in Australia to examine their efficacy with regard to medium to large macropodids. Field trials of the reflectors are problematic and difficult to design rigorously, so we chose to examine the behavioural response of two captive macropodid species (Macropus rufus and M. rufogriseus) to the reflectors on a simulated road in order to derive some indication as to their efficacy. The behavioural response to the reflectors was negligible for both species and not consistent with an aversive effect to deter road use or crossing. We conclude that they would be of little value in our efforts to reduce the frequency of collisions of kangaroos or wallabies with vehicles in Australia.

Kangaroo–vehicle collisions are frequent on Australian highways. Despite high economic costs, detrimental effects on animal welfare, and potential impacts on population viability, little research has been done to investigate the impact of road mortality on kangaroo populations, where and why accidents occur, and how the collisions can be mitigated. We therefore collected data on species (Macropus rufus, M. giganteus, M. fuliginosus, M. robustus), sex and age of kangaroos killed on a 21.2-km bitumenised section of outback highway over 6 months in far western New South Wales, Australia. The spatial and temporal distribution of road-killed kangaroos was investigated in relation to the cover and quality of road-side vegetation, road characteristics, the density of kangaroos along the road, climatic variables and traffic volume. A total of 125 kangaroos were found killed on the road at a rate of 0.03 deaths km–1 day–1. Grey kangaroos of two species (M. giganteus, M. fuliginosus) were under-represented in the road-kill sample in comparison with their proportion in the source population estimated during the day. No bias towards either sex was found. The age structure of road-killed kangaroos was similar to age structures typical of source kangaroo populations. Road-kills mainly occurred in open plains country. In road sections with curves or stock races, road-kill frequencies were higher than expected. Greater cover and greenness of roadside vegetation at the verge probably attracted kangaroos to the road and variation in this vegetation affected the spatial distribution of road-kills. The temporal distribution of road-kills was positively correlated with the volume of night-time traffic. The probability of a kangaroo–vehicle collision increased exponentially with traffic volume. Results are discussed in relation to the potential for mitigation of kangaroo–vehicle collisions.

Context Auditory devices used to deter wildlife are a potentially humane and effective way of minimising deleterious interactions with humans and their livelihoods and have been used successfully for many species around the world. Acoustic cues can be used to manipulate anti-predator behaviour, encouraging animals to forage elsewhere. Employing acoustics derived from natural sources to make use of innate behavioural responses has been suggested to outperform novel or artificial sounds; however, anti-predator strategies vary among sympatric species and will influence the utility of acoustic stimuli for deterring wildlife. Aims We aimed to test the interaction between the source of origin (natural or novel) and species traits (anti-predator strategy – grouping behaviour) on the efficacy of using acoustic stimuli to elicit alarm responses for two species in the family Macropodidae commonly associated with browsing on forest plantation seedlings; the red-necked pademelon (Thylogale thetis) and the red-necked wallaby (Macropus rufogriseus banksianus). Methods We tested these factors in captivity using playback experiments of acoustic stimuli and monitored the behavioural responses of subjects. Results Red-necked pademelons exhibited strong responses to bioacoustic and novel stimuli but did not greatly differentiate among them. Short-term habituation to predator calls was detected whereas responsiveness to novel sounds increased. Red-necked wallabies most strongly responded to conspecific distress calls, showing no sign of short-term habituation. Conclusions Results from the present and other studies suggest that bioacoustic deterrents, particularly those utilising natural conspecific sounds, aimed at communicating danger, have the potential to play an important role in non-lethal wildlife management, although that responsiveness varies with the form of anti-predator strategies employed. Implications If alarm responses translate into subjects vacating targeted areas, then there is some potential to implement non-lethal acoustic deterrents for macropodids alongside other management measures aimed at preventing impacts on primary production. Problematically, our experiments showed that without accurate acoustic delivery, particularly of sounds with infrasonic components, the development of effective bioacoustic deterrents may remain stymied.

Context. Prescribed (or controlled) burning is frequently advocated as a means of reducing fuel loads in peri-urban forests to minimise the risk of high-intensity wildfires. An important consideration in prescribed burns is the impact on native wildlife.


Aims. An opportunity arose to follow the movements of radio-collared peri-urban swamp wallabies during a prescribed burn and after an unexpected wildfire in the same location a short time later. Movement data was used to assess the relative impacts of the prescribed burn and wildfire on mortality, emigration and habitat use; the behavioural responses and methods of avoidance used by swamp wallabies in response to an oncoming fire front; and the management implications for wildlife that inhabit fire-prone habitats in proximity to human settlement where wildfire mitigation is necessary.


Methods. Here we report on the movements of radio-collared swamp wallabies, Wallabia bicolor, before, during and after a prescribed fire and after a wildfire on the same site 6 months later.


Key results. No radio-collared swamp wallabies were killed during the prescribed burn and only one wallaby was observed to emigrate from the area post-fire. This contrasted to the wildfire where one wallaby died during or just after the fire and another perished in the post-fire environment a few months later. The wildfire also increased emigration post-fire.


Conclusions. We demonstrate that wallabies can avoid fire fronts and that this avoidance behaviour may be more successful during cooler fires. The prescribed burn provided a suitable habitat for wallabies but did not result in a shift in habitat preference.


Implications. Mitigation of the impact of prescribed burns on swamp wallabies may be achieved by allowing sufficient time for habitat complexity to re-establish between burns.

This paper presents an investigation into the legal history of Australia's kangaroos. It aims to provide a detailed analysis of how the law and policy governing the killing of kangaroos has evolved over time in response to changing public perceptions. This history begins with the pre-European period and traces the impact of European colonisation, early growth of the commercial kangaroo industry, and the increased role of science and regulation upon kangaroos. The paper critiques the historical designation of kangaroos as 'pests' that need to be 'managed' and argues that such an approach is inconsistent with current scientific understanding. As this 'pest' status has fallen in importance there has been a shift in regulatory goals from damage mitigation to resource utilisation, although government planning and policy continue to cite damage mitigation alongside objectives to maintain viable populations and a sustainable and commercially viable industry. While the kangaroo industry's current focus is upon the 'sustainable use of wildlife', the history of attitudes towards kangaroos as 'pests' is so deeply and widely entrenched that it is impossible for the industry to meet welfare standards. The article concludes that the commercial kangaroo industry does not have any clearly defined policy benefit and should be reassessed to take greater account of the impact it has on ecosystems and kangaroo welfare.