Do wildlife warning reflectors elicit aversion in captive macropods?

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. © CSIRO 2006

Contradiction and complacency shape attitudes towards the toll of roads on wildlife

© 2016 by the authors; licensee MDPI, Basel, Switzerland. Most people in the world now live in cities. Urbanisation simultaneously isolates people from nature and contributes to biodiversity decline. As cities expand, suburban development and the road infrastructure to support them widens their impact on wildlife. Even so, urban communities, especially those on the peri-urban fringe, endeavour to support biodiversity through wildlife friendly gardens, green spaces and corridors, and conservation estates. On one hand, many who live on city fringes do so because they enjoy proximity to nature, however, the ever increasing intrusion of roads leads to conflict with wildlife. Trauma (usually fatal) to wildlife and (usually emotional and financial) to people ensues. Exposure to this trauma, therefore, should inform attitudes towards wildlife vehicle collisions (WVC) and be linked to willingness to reduce risk of further WVC. While there is good anecdotal evidence for this response, competing priorities and better understanding of the likelihood of human injury or fatalities, as opposed to wildlife fatalities, may confound this trend. In this paper we sought to explore this relationship with a quantitative study of driver behaviour and attitudes to WVC from a cohort of residents and visitors who drive through a peri-urban reserve (Royal National Park) on the outskirts of Sydney, Australia. We distributed a self-reporting questionnaire and received responses from 105 local residents and 51 visitors to small townships accessed by roads through the national park. We sought the respondents’ exposure to WVC, their evasive actions in an impending WVC, their attitudes to wildlife fatalities, their strategies to reduce the risk of WVC, and their willingness to adopt new ameliorative measures. The results were partitioned by driver demographics and residency. Residents were generally well informed about mitigation strategies but exposure led to a decrease in viewing WVC as very serious. In addition, despite most respondents stating they routinely drive slower when collision risk is high (at dusk and dawn), our assessment of driving trends via traffic speeds suggested this sentiment was not generally adhered to. Thus we unveil some of the complexities in tackling driver’s willingness to act on reducing risk of WVC, particularly when risk of human trauma is low

Frequency and causes of kangaroo-vehicle collisions on an Australian outback highway

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. © CSIRO 2006

Predator scent induces differing responses in two sympatric macropodids

When prey species encounter the scent of a predator they must make a decision on how to respond. This may be either to ignore, flee, hide or alarm call. While many species are able to derive detailed information from the chemical cues associated with predator scent, for some the decision to respond is often made without being able to identify the actual location and intentions of the predator. Depending on the sociality and ecology of the species, it may pay to flee or to engage in predator inspection where knowledge is impure. We tested for this in two sympatric marsupial macropodids, the parma wallaby (Macropus parma) and the red-necked pademelon (Thylogale thetis), as little is known of how these species detect and respond to olfactory cues of predation risk. We observed that, when presented with a synthetic predator scent mimicking dog urine, the social forager, T. thetis, tended to spend more time close to the predator odour, while the solitary forager, M. parma, exhibited an aversive response. The results suggest that social and ecological constraints on the sensory modalities used in predator detection may influence how macropodids respond to olfactory predator cues. © CSIRO 2005

Suitability of acoustics as non-lethal deterrents for macropodids: The influence of origin, delivery and anti-predator behaviour

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. © 2011 CSIRO

'Pest' and resource: A legal history of Australia's kangaroos

This paper presents an investigation into the legal history of Australias 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 industrys 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 welfar

Effects of spines and thorns on Australian arid zone herbivores of different body masses

We investigated the effects of thorns and spines on the feeding of 5 herbivore species in arid Australia. The herbivores were the rabbit ( Oryctolagus cuniculus ), euro kangaroo ( Macropus robustus ), red kangaroo ( Macropus rufus ), sheep ( Ovis aries ), and cattle ( Bos taurus ). Five woody plants without spines or thorns and 6 woody plants with thorns were included in the study. The spines and thorns were not found to affect the herbivores' rates of feeding (items ingested/min), but they did reduce the herbivores' rates of biomass ingestion (g-dry/item). The reduction in biomass ingested occurred in two ways: at a given diameter, twigs with spines and thorns had less mass than undefended plants, and the herbivores consumed twigs with smaller diameters on plants with spines and thorns. The relative importance of the two ways that twigs with spines and thorns provided less biomass varied with herbivore body mass. Reduced twig mass was more important for small herbivores, while large herbivores selected smaller diameters. The effectiveness of spines and thorns as anti-herbivore defenses did not vary with the evolutionary history of the herbivores (i.e. native vs. introduced). Spines and thorns mainly affected the herbivores' selection of maximum twig sizes (reducing diameter and mass), but the minimum twig sizes selected were also reduced.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47795/1/442_2004_Article_BF00317715.pd

Arctic marine secondary organic aerosol contributes significantly to summertime particle size distributions in the Canadian Arctic Archipelago

Summertime Arctic aerosol size distributions are strongly controlled by natural regional emissions. Within this context, we use a chemical transport model with sizeresolved aerosol microphysics (GEOS-Chem-TOMAS) to interpret measurements of aerosol size distributions from the Canadian Arctic Archipelago during the summer of 2016, as part of the "NETwork on Climate and Aerosols: Addressing key uncertainties in Remote Canadian Environments" (NETCARE) project. Our simulations suggest that condensation of secondary organic aerosol (SOA) from precursor vapors emitted in the Arctic and near Arctic marine (ice-free seawater) regions plays a key role in particle growth events that shape the aerosol size distributions observed at Alert (82.5° N, 62.3° W), Eureka (80.1° N, 86.4° W), and along a NETCARE ship track within the Archipelago. We refer to this SOA as Arctic marine SOA (AMSOA) to reflect the Arctic marine-based and likely biogenic sources for the precursors of the condensing organic vapors. AMSOA from a simulated flux (500 μgm-2 day-1, north of 50° N) of precursor vapors (with an assumed yield of unity) reduces the summertime particle size distribution model-observation mean fractional error 2- to 4-fold, relative to a simulation without this AMSOA. Particle growth due to the condensable organic vapor flux contributes strongly (30 %-50 %) to the simulated summertime-mean number of particles with diameters larger than 20 nm in the study region. This growth couples with ternary particle nucleation (sulfuric acid, ammonia, and water vapor) and biogenic sulfate condensation to account for more than 90% of this simulated particle number, which represents a strong biogenic influence. The simulated fit to summertime size-distribution observations is further improved at Eureka and for the ship track by scaling up the nucleation rate by a factor of 100 to account for other particle precursors such as gas-phase iodine and/or amines and/or fragmenting primary particles that could be missing from our simulations. Additionally, the fits to the observed size distributions and total aerosol number concentrations for particles larger than 4 nm improve with the assumption that the AMSOA contains semivolatile species: the model-observation mean fractional error is reduced 2- to 3-fold for the Alert and ship track size distributions. AMSOA accounts for about half of the simulated particle surface area and volume distributions in the summertime Canadian Arctic Archipelago, with climaterelevant simulated summertime pan-Arctic-mean top-of-theatmosphere aerosol direct (-0:04Wm-2) and cloud-albedo indirect (-0:4Wm-2) radiative effects, which due to uncertainties are viewed as an order of magnitude estimate. Future work should focus on further understanding summertime Arctic sources of AMSOA

Dynamic social networks in guppies (Poecilia reticulata)

One of the main challenges in the study of social networks in vertebrates is to close the gap between group patterns and dynamics. Usually scan samples or transect data are recorded to provide information about social patterns of animals, but these techniques themselves do not shed much light on the underlying dynamics of such groups. Here we show an approach which captures the fission-fusion dynamics of a fish population in the wild and demonstrates how the gap between pattern and dynamics may be closed. Our analysis revealed that guppies have complex association patterns that are characterised by close strong connections between individuals of similar behavioural type. Intriguingly, the preference for particular social partners is not expressed in the length of associations but in their frequency. Finally, we show that the observed association preferences could have important consequences for transmission processes in animal social networks, thus moving the emphasis of network research from descriptive mechanistic studies to functional and predictive ones. © 2014 Springer-Verlag Berlin Heidelberg