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Australian National University (2012)

Is the dingo top dog ? : the influence of dingo management on the behaviour of introduced carnivores in arid Australia, with implications for native fauna conservation

Brawata, Renee Louise

Titre : Is the dingo top dog ? : the influence of dingo management on the behaviour of introduced carnivores in arid Australia, with implications for native fauna conservation

Auteur : Brawata, Renee Louise

Université de soutenance : Australian National University

Grade : Doctor of Philosophy (PhD) 2012

Résumé
An improved understanding of how ecosystems function is important for effective natural resource management and biodiversity conservation. Recent research suggests that top-order predators have important ecological roles in many ecosystems through controlling populations of smaller predators. This thesis examined how the management of Australia’s apex predator, the dingo (Canis lupus dingo), influenced the activity and behaviour of two introduced mesopredators, the red fox (Vulpes vulpes) and feral cat (Felis catus) and select prey species. The aim was to increase our understanding of the role dingoes may play in the conservation of endangered fauna through the trophic regulation of exotic mesopredators. The study monitored the activity and behaviour of dingoes, foxes, feral cats and select prey species at five sites in arid Australia. Dingo management varied between the study sites. Sites included areas where dingoes remained uncontrolled, where dingoes were controlled through exclusion fencing and where 1080 poison baiting was conducted. At each site the activity of predators and prey, including macropods, rabbits and small vertebrates was monitored over two summers. Sampling times included prior to, three months post and one year post a significant rainfall event. Transects and scent stations were used to measure activity while behaviour was monitored through direct observation and the use of a thermal imaging camera attached to a remote recording system. Results showed the management of dingoes to be a key determinant of the activity of foxes and select prey, including macropods, rabbits and small mammals. Feral cat activity showed a positive response to both dingo and fox control through poison baiting. Dingo management also affected the activity of mesopredators around shared resources, particularly in proximity to water resources. Both feral cats and foxes showed an avoidance response to the presence of dingoes around water points, and again feral cats displayed an increased response to the removal of both canids. Habitat use by mesopredators did not appear to be affected by dingo management, and while foxes showed a behavioural avoidance response, limited data was collected on the response of feral cats to dingoes at shared food and water resources so results were inconclusive. The results of this study supported the presence of top-down regulation occurring in the arid ecosystems under some conditions and that behavioural mechanisms, such as avoidance, are important in the ability of dingoes to regulate smaller predator populations. While arid ecosystems are traditionally viewed as "bottom-up" or productivity driven, evidence from this research showed that while the strength of trophic regulation by dingoes may fluctuate, top-down effects occurred both prior to and post significant rainfall events at the study sites. In particular, strong relationships were found between dingo management, fox activity and fox behaviour at the study sites regardless of rainfall. In conclusion, it may be that dingoes provide a net benefit to prey populations, particularly medium-sized and small mammals, through reducing predatory impacts of foxes and under some conditions, feral cats. Thus retaining dingo populations in some ecosystems may assist in the management of biodiversity over the long term, including the conservation of native fauna populations susceptible to fox and feral cat predation. While further research into the trophic effects of dingoes in other bioregions is recommended, through improving our understanding of such trophic interactions, results from this research could assist managers in making more ecologically informed decisions about control of top-order carnivores in arid areas.

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