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Ballard, Guy
- PublicationSocial, conservation and economic implications of rabies in Australia(Royal Zoological Society of New South Wales, 2017)
;Sparkes, Jessica; ; Biophilia, our inherent love of living things, is a major driver of the modern conservation ethic worldwide. Australians are particularly fond of wildlife and consequently, our fauna are key to our national image. As a nation, we are known for our relatively carefree attitude towards some of the world's most dangerous animals, including venomous snakes and spiders, as well as sharks. This has arisen largely because we are familiar with these species, understand the actual level of risk they pose and have some idea of how to safely interact with them. Unfortunately, the relationship between Australians and our wildlife could change significantly. Canine rabies, an infamous, fatal, viral zoonosis, is now less than 300 kilometers from the Australian mainland. We must face the possibility of a 'when', rather than 'if' scenario and begin to plan for rabies management on a continent where virtually the entire population is naïve. Human and animal health would be affected. People, domestic animals and wildlife may die. Perhaps worse, in terms of scale, is the likely change in the Australian way of life, including the way we perceive, value and interact with wildlife, pets and livestock. Of course, rabies is endemic in many other countries and people continue to actively engage in conservation programs, but these people have had a long time to come to terms with the risk in their midst and many undergo prophylactic vaccination to enable them to work with wildlife. Here, we discuss Australia's impending future with particular regard to how canine rabies could change our lives, the impacts it could have on wildlife conservation and the steps we must take to be prepared. - PublicationInvasive species and their impacts on agri-ecosystems: issues and solutions for restoring ecosystem processes
Humans are the most invasive of vertebrates and they have taken many plants and animals with them to colonise new environments. This has been particularly so in Australasia, where Laurasian and domesticated taxa have collided with ancient Gondwanan ecosystems isolated since the Eocene Epoch. Many plants and animals that humans introduced benefited from their pre-adaptation to their new environments and some became invasive, damaging the biodiversity and agricultural value of the invaded ecosystems. The invasion of non-native organisms is accelerating with human population growth and globalisation. Expansion of trade has seen increases in purposeful and accidental introductions, and their negative impacts are regarded as second only to activities associated with human population growth. Here, the theoretical processes, economic and environmental costs of invasive alien species (i.e. weeds and vertebrate pests) are outlined. However, defining the problem is only one side of the coin. We review some theoretical underpinnings of invasive species science and management, and discuss hypotheses to explain successful biological invasions. We consider desired restoration states and outline a practical working framework for managing invasive plants and animals to restore, regenerate and revegetate invaded Australasian ecosystems.
- PublicationSatellite and telecommunication alert system for foot-hold trapping(CSIRO Publishing, 2021)
; ; ; ;Croft, Simon ;Lawson, GeoffContext. Improving the welfare outcomes for captured animals is critically important and should underpin 'best-practice' trapping. Most Australian States and Territories have regulations and guidelines that form a legal framework for the maximum number of hours an animal can be restrained in a trap. Because servicing all traps within preferred time frames (less than 24 h) can be logistically difficult or is considered undesirable for efficacy reasons, some jurisdictions have adopted relatively long trap-checking intervals (up to 72 h).
Aims. We developed and tested the signal transmission and alert efficacy of a foot hold-trap alert system, based on Celium technology, so as to advise trappers of the activation of individual foot-hold traps, even in remote locations.
Methods. We refined the Celium trap-alert system and designed a below-ground wireless node that transmits a message via satellite or by using the cellular system when a foot-hold trap is sprung. We tested signal transmission and alert efficacy in three locations, with a focus in Australia.
Key results. Transmission of signals from nodes to hubs and to a smart-phone application were used to resolve interference problems and to identify signal limitations and strengths. During the capture of 34 dingoes, 91% of captures resulted in an alert being received. False negatives were attributed to technical issues with nearby transmitters swamping signals, and software problems that have since been resolved. In 40 captures of dogs and foxes, only one trap-alert transmitter (mole) was uncovered by a target animal and no devices were damaged by animals post-capture.
Conclusions. This cable-less trap-alert system successfully uses both cellular and satellite networks to transmit messages from desert and coastal locations to trappers, in Australia. We confirmed that this trap-alert system is not detected by target predators in the areas tested and can be effectively used to alert trappers when traps have been sprung.
Implications. This trap-alert system provides a tool to improve welfare outcomes for trapped target and non-target animals through Australia and New Zealand and wherever trapping occurs. It, furthermore, provides a solution to checking traps daily when the distance to and between traps cannot be covered within an appropriate time frame. Although trap alerts can never replace the value of daily trap checking by the trapper, they provide a solution to a management problem, namely, one of accessibility to sites.
- PublicationCanine rabies in Australia: Modelling spread through the landscape(Australasian Society for Infectious Diseases, 2014)
;Sparkes, Jessica; ; ; Introduction: Canine rabies, a fatal viral zoonosis, is now less than 300 kilometres from Indonesian archipelago. To respond to this imminent threat, we need to model how rabies will spread through Australian ecosystems, to develop effective rabies management plans. This will improve our chances of minimising reaction times and containing outbreaks. Aims: To quantify contact rates, abundance, population turnover and dog bite frequency, in order to inform models of canine rabies spread. This is essential for identifying critical control points. - PublicationSignaling systems in Australian wild dogs: Who's calling and who cares?Alarm and distress vocalizations are important anti-predator strategies for many species. An alarm call is a particular vocal response to potential or actual danger, whereas a distress call is an involuntary emotional response to a similar situation and/or stimuli. Alarm and distress calls are often associated with prey species. Australian wild dogs (dingoes, feral dogs and their hybrids) have been observed utilizing similar strategies in response to intense human interactions. We analyzed the spectral (frequency and amplitude shifts) and temporal (call length) components of vocalizations recorded from trapped wild dogs and compared these to vocalizations from captive individuals under non-stressful situations. (i) Vocal responses to trapping are not restricted to distress calls. (ii) The structure of wild dog vocalizations differs across sites, suggesting local dialects or individual differences exist. (iii) Age and social status may affect the type of call elicited by an individual. Understanding the differences in vocalizations of wild dogs in varying environments is vital to the success of remote acoustic monitoring endeavors and to the improvement of wildlife management as a proxy for individual stress. Understanding how vocal communication varies across groups will aid in understanding the evolution of the dingo.
- PublicationConventional distance sampling versus strip transects and abundance indices for estimating abundance of greater gliders (Petauroides volans) and eastern ringtail possums (Pseudocheirus peregrinus)Context: Accurate estimates of abundance are extremely useful for wildlife management and conservation. Estimates generated from distance sampling are typically considered superior to strip transects and abundance indices, as the latter do not account for probability of detection, thereby risking significant error.
Aims: To compare density estimates generated from conventional distance sampling (CDS) of arboreal marsupials with strip transect density estimates and abundance indices.
Methods: Off-track CDS and strip transects were used to estimate densities of P. volans and P. peregrinus across ∼ 2.6 km2 of remnant eucalypt forest at Mt Duval in north-eastern New South Wales.
Key Results: CDS density estimates for P. volans (1.36 ha−1, 95% confidence interval (CI) of 1.07-1.72 ha−1) and P. peregrinus (0.28 ha−1, 95% CI 0.22-0.35 ha−1) were consistent with densities reported in other studies conducted in open eucalypt forests. A strip transect width of 40m for P. volans resulted in a collective set of values for density (1.35 ha−1), error (s.e. ∓ 0.14), precision (cv 0.10) and 95% CI (1.07–1.62 ha−1) closest to those associated with the CDS-generated density estimate (1.36 ha−1, s.e. ∓ 0.15, cv 0.10, 95% CI 1.07–1.72 ha−1). Strip widths of 10 to 40m resulted in density estimates for P. peregrinus closest to those generated through CDS, but much less precise.
Conclusions: Although a 40-m wide strip transect provided a robust density estimate for P. volans at Mt Duval, this is unlikely to be consistent across different study areas. Strip transects provided less precise density estimates, or underestimated P. peregrinus density at Mt Duval, when compared with CDS density estimates. CDS should be favoured over strip transects or abundance indices for estimating P. volans and P. peregrinus abundance, because it is capable of providing more meaningful and robust abundance estimates by accounting for the probability of detection from the transect line across different habitats.
Implications: Researchers, conservation managers and decision makers should be aware that common methods for assessing arboreal marsupial abundance have serious potential weaknesses. Thus, it would be prudent to invest in studies that address imperfect detection to improve the quality of monitoring data. - PublicationEnvisioning the future with 'compassionate conservation': An ominous projection for native wildlife and biodiversity(Elsevier BV, 2020-01)
;Callen, Alex ;Hayward, Matt W ;Klop-Toker, Kaya ;Allen, Benjamin L; ;Beranek, Chad T ;Broekhuis, Femke ;Bugir, Cassandra K ;Clarke, Rohan H ;Clulow, John ;Clulow, Simon ;Daltry, Jennifer C ;Davies-Mostert, Harriet T ;Di Blanco, Yamil E ;Dixon, Victoria; ;Howell, Lachlan G ;Kerley, Graham I H ;Legge, Sarah M ;Lenga, Dean J ;Major, Tom ;Montgomery, Robert A ;Moseby, Katherine ;Meyer, Ninon ;Parker, Dan M ;Periquet, Stephanie ;Read, John ;Scanlon, Robert J ;Shuttleworth, Craig ;Tamessar, Cottrell T ;Taylor, William Andrew ;Tuft, Katherine ;Upton, Rose M O ;Valenzuela, Marcia ;Witt, Ryan RWuster, WolfgangThe 'Compassionate Conservation' movement is gaining momentum through its promotion of 'ethical' conservation practices based on self-proclaimed principles of 'first-do-no-harm' and 'individuals matter'. We argue that the tenets of 'Compassionate Conservation' are ideological - that is, they are not scientifically proven to improve conservation outcomes, yet are critical of the current methods that do. In this paper we envision a future with 'Compassionate Conservation' and predict how this might affect global biodiversity conservation. Taken literally, 'Compassionate Conservation' will deny current conservation practices such as captive breeding, introduced species control, biocontrol, conservation fencing, translocation, contraception, disease control and genetic introgression. Five mainstream conservation practices are used to illustrate the far-reaching and dire consequences for global biodiversity if governed by 'Compassionate Conservation'. We acknowledge the important role of animal welfare science in conservation practices but argue that 'Compassionate Conservation' aligns more closely with animal liberation principles protecting individuals over populations. Ultimately we fear that a world of 'Compassionate Conservation' could stymie the global conservation efforts required to meet international biodiversity targets derived from evidenced based practice, such as the Aichi targets developed by the Convention on Biological Diversity and adopted by the International Union for the Conservation of Nature and the United Nations.
- PublicationEffects of Sex and Reproductive State on Interactions between Free-Roaming Domestic Dogs(Public Library of Science, 2014)
;Sparkes, Jessica; ; ; Free-roaming dogs ('Canis familiaris') are common worldwide, often maintaining diseases of domestic pets and wildlife. Management of these dogs is difficult and often involves capture, treatment, neutering and release. Information on the effects of sex and reproductive state on intraspecific contacts and disease transmission is currently lacking, but is vital to improving strategic management of their populations. We assessed the effects of sex and reproductive state on short-term activity patterns and contact rates of free-roaming dogs living in an Australian Indigenous community. Population, social group sizes and rates of contact were estimated from structured observations along walked transects. Simultaneously, GPS telemetry collars were used to track dogs' movements and to quantify the frequency of contacts between individual animals. We estimated that the community's dog population was 326±52, with only 9.8±2.5% confined to a house yard. Short-term activity ranges of dogs varied from 9.2 to 133.7 ha, with males ranging over significantly larger areas than females. Contacts between two or more dogs occurred frequently, with entire females and neutered males accumulating significantly more contacts than spayed females or entire males. This indicates that sex and reproductive status are potentially important to epidemiology, but the effect of these differential contact rates on disease transmission requires further investigation. The observed combination of unrestrained dogs and high contact rates suggest that contagious disease would likely spread rapidly through the population. Pro-active management of dog populations and targeted education programs could help reduce the risks associated with disease spread. - PublicationInferring inter‑colony movement within metapopulations of yellow‑footed rock‑wallabies using estimates of kinship
Understanding the exchange of individuals between wildlife populations, particularly those with naturally fragmented habitats, is important for the effective management of these species. This is of particular consequence when the species is of conservation concern, and isolated populations may be lost due to pressures from predation or competition, or catastrophic events such as wildfire. Here we demonstrate the use kinship and population structure analysis to show potential recent movement between colonies in metapopulations of yellow-footed rock-wallaby (Petrogale xanthopus Gray 1854) at two sites in the Grey Range of Queensland, and at four sites in the Gawler Ranges of South Australia. These colonies are also compared to a single colony from the Flinders Ranges, a connected landscape of rock-wallaby habitat. Using reduced representation next-generation sequencing, we acquired and filtered a set of similar to 17,000 single-nucleotide polymorphisms to examine population genetic variation, structure and relationships within populations, and also identify putative migrants. Initial STRUCTURE analysis re-confirmed each population should be considered separately. Tests of population genetic variation identify several colonies appearing to be experiencing genetic erosion, also with low calculated effective population sizes (Ne = 4.5-36.6). Pairwise comparisons of individual relatedness (relatedness coeffiecients; r) implied several contemporary movement events between colonies within both the Gawler and Grey Ranges (r > 0.125), which was then affirmed with tests for putative first generation migrants. These results are of particular note in South Australia, where threat abatement (management of key predators and competitors) may facilitate dispersion. Additionally, in Queensland, colonies are separated by anthropogenic barriers: predator exclusion fencing designed to exclude dingoes (Canis familiaris) from grazing land, which may hinder dispersal. This work highlights the usefulness of population genetics to inform management outcomes in wildlife, in this case, highlighting the need for threatened species management at the landscape level.
- PublicationHuman-resource subsidies alter the dietary preferences of a mammalian top predator(Springer, 2014)
;Newsome, Thomas M; ; ;van de Ven, Remy ;Story, GeorgeannaDickman, ChrisResource subsidies to opportunistic predators may alter natural predator-prey relationships and, in turn, have implications for how these predators affect co-occurring prey. To explore this idea, we compared the prey available to and eaten by a top canid predator, the Australian dingo ('Canis lupus dingo'), in areas with and without human-provided food. Overall, small mammals formed the majority of dingo prey, followed by reptiles and then invertebrates. Where human-provided food resources were available, dingoes ate them; 17% of their diet comprised kitchen waste from a refuse facility. There was evidence of dietary preference for small mammals in areas where human-provided food was available. In more distant areas, by contrast, reptiles were the primary prey. The level of seasonal switching between small mammals and reptiles was also more pronounced in areas away from human-provided food. This reaffirmed concepts of prey switching but within a short, seasonal time frame. It also confirmed that the diet of dingoes is altered where human-provided food is available. We suggest that the availability of anthropogenic food to this species and other apex predators therefore has the potential to alter trophic cascades.