Dingo Populations Research Articles

More than Mere Numbers: The Impact of Lethal Control on the Social Stability of a Top-Order Predator

Population control of socially complex species may have profound ecological implications that remain largely invisible if only their abundance is considered. Here we discuss the effects of control on a socially complex top-order predator, the dingo (Canis lupus dingo). Since European occupation of Australia, dingoes have been controlled over much of the continent. Our aim was to investigate the effects of control on their abundance and social stability. We hypothesized that dingo abundance and social stability are not linearly related, and proposed a theoretical model in which dingo populations may fluctuate between three main states: (A) below carrying capacity and socially fractured, (B) above carrying capacity and socially fractured, or (C) at carrying capacity and socially stable. We predicted that lethal control would drive dingoes into the unstable states A or B, and that relaxation of control would allow recovery towards C. We tested our predictions by surveying relative abundance (track density) and indicators of social stability (scent-marking and howling) at seven sites in the arid zone subject to differing degrees of control. We also monitored changes in dingo abundance and social stability following relaxation and intensification of control. Sites where dingoes had been controlled within the previous two years were characterized by low scent-marking activity, but abundance was similar at sites with and without control. Signs of social stability steadily increased the longer an area was allowed to recover from control, but change in abundance did not follow a consistent path. Comparison of abundance and stability among all sites and years demonstrated that control severely fractures social groups, but that the effect of control on abundance was neither consistent nor predictable. Management decisions involving large social predators must therefore consider social stability to ensure their conservation and ecological functioning.

Keystone effects of an alien top-predator stem extinctions of native mammals

Alien predators can have catastrophic effects on ecosystems and are thought to be much more harmful to biodiversity than their native counterparts. However, trophic cascade theory and the mesopredator release hypothesis predict that the removal of top predators will result in the reorganization of trophic webs and loss of biodiversity. Using field data collected throughout arid Australia, we provide evidence that removal of an alien top-predator, the dingo, has cascading effects through lower trophic levels. Dingo removal was linked to increased activity of herbivores and an invasive mesopredator, the red fox (Vulpes vulpes), and to the loss of grass cover and native species of small mammals. Using species distribution data, we predict that reintroducing or maintaining dingo populations would produce a net benefit for the conservation of threatened native mammals across greater than 2.42 x 10(6) km(2) of Australia. Our study provides evidence that an alien top predator can assume a keystone role and be beneficial for biodiversity conservation, and also that mammalian carnivores more generally can generate strong trophic cascades in terrestrial ecosystems.

A national framework for research on trophic regulation by the Dingo in Australia

There is increasing evidence that the Dingo Canis lupus dingo plays an important ecological role as a trophic regulator in Australian ecosystems. However, there is sufficient remaining uncertainty about the nature of this role as to hinder the development of effective management policies. This review defines strategic directions for future research on the trophic role of Dingoes by developing a national Dingo research framework. The framework aims to increase our knowledge of the influence that Dingoes have on the maintenance of biodiversity, thereby encouraging Dingo conservation and the refinement of current land-use practices. The framework begins by identifying four major bioclimatic zones across Australia that pose different questions and challenges for Dingo research. For each zone we construct a model that identifies major interactions between Dingoes and key prey or competitor species, and then used the models to identify key research needs, the possible advantages of maintaining Dingo populations within each zone, and ways to tease out unstudied interactions. Important questions identified in the review include the effects of Dingoes on native marsupial populations, vegetation communities, herbivore diets, the use of structural refugia by mesopredators, predator and prey behaviour, and the effect of habitat modification on these interactions. We briefly review legislative constraints and other factors, such as the ongoing hybridization of Dingo populations with domestic dog breeds, that may impede future studies. If research activities follow this framework, we believe that policy and management will be better informed, benefiting both the Dingo and the natural ecosystems and production systems where it occurs.

Threatened species indicate hot-spots of top-down regulation

The introduction of alien mesopredators and herbivores has been implicated as the main driver of mammalian extinction in Australia. Recent studies suggest that the devastating effects of invasive species are mitigated by top-order predators. The survival of many threatened species may therefore depend on the presence and ecological functioning of large predators. Australia’s top predator, the dingo (Canis lupus dingo), has been intensively persecuted across the continent and it is extremely rare to find dingo populations that are not being subjected to lethal control. We predicted that the presence of threatened species point out places where dingo populations are relatively intact, and that their absence may indicate that dingoes are either rare or socially fractured. A comparison of a site which harbors a threatened marsupial, the kowari (Dasyuroides byrnei), and a neighboring site where the kowari is absent, offers support for this suggested pattern.

Hybridisation between the dingo, Canis lupus dingo, and the domestic dog, Canis lupus familiaris, in Victoria: a critical review

This paper reviews two separate population models proposed for a group of wild canids inhabiting the Victorian eastern highlands and re-analyses some of the data used. The first model was based upon two studies that used eight skull measurements in a canonical variate equation. Those studies classified population samples into three separate groups consisting of dingoes, feral domestic dogs and their hybrids. The second model, based upon a later study, classified a separate and additional population sample on the basis of both coat colour and physical appearance, but also cross-referenced the classifications to their canonical scores. That study rejected the model of three separate canid groups and the ability of the canonical variate equation to differentiate ‘pure’ dingoes from other canids. Instead the population was classified as a single group of dingo-like wild canids with an increased range in the variability of their physical characteristics compared to the original dingo population. After a re-evaluation of the data from the latter study and careful examination of the limitations of the canonical variate equation, the evidence presented here supports the population model of a single group of wild canids. Theoretical considerations associated with these two population models are discussed, as are the limitations of the canonical variate equation to classify the Victorian eastern highlands and other Australian wild canid populations.

An evaluation of genetic analyses, skull morphology and visual appearance for assessing dingo purity: implications for dingo conservation

The introgression of domestic dog genes into dingo populations threatens the genetic integrity of ‘pure’ dingoes. However, dingo conservation efforts are hampered by difficulties in distinguishing between dingoes and hybrids in the field. This study evaluates consistency in the status of hybridisation (i.e. dingo, hybrid or dog) assigned by genetic analyses, skull morphology and visual assessments. Of the 56 south-east Queensland animals sampled, 39 (69.6%) were assigned the same status by all three methods, 10 (17.9%) by genetic and skull methods, four (7.1%) by genetic and visual methods; and two (3.6%) by skull and visual methods. Pair-wise comparisons identified a significant relationship between genetic and skull methods, but not between either of these and visual methods. Results from surveying 13 experienced wild dog managers showed that hybrids were more easily identified by visual characters than were dingoes. A more reliable visual assessment can be developed through determining the relationship between (1) genetics and phenotype by sampling wild dog populations and (2) the expression of visual characteristics from different proportions and breeds of domestic dog genes by breeding trials. Culling obvious hybrids based on visual characteristics, such as sable and patchy coat colours, should slow the process of hybridisation.

Dingo Control or Conservation? Attitudes Towards Urban Dingoes (Canis lupus dingo) as an Aid to Dingo Management

Author(s): Atkinson, Sarah A. | Abstract: There is surprisingly little research into urban dingoes, even though urban areas in Australia are rapidly increasing, along with a concurrent increase in the number of reported conflicts with wildlife. Misguided and so-called ad hoc management of dingo populations, often caused by an over-reaction by the media to a situation, is commonly accredited for these conflicts. There can also be confusion over whom to contact when problems arise. A survey of the attitudes of parents of school-aged children towards urban dingoes in their area was carried out in Maroochy Shire, in South-East Queensland. Respondents generally believed that dingoes could be dangerous, but they preferred that control methods used be ‘humane’. Most respondents obtained their knowledge of dingoes from television and news media; about ¾ of respondents requested information regarding dingo management issues. The Queensland Parks and Wildlife Service was selected by a majority of respondents as the preferred agency to deal with dingo management.

Assessing the taxonomic status of dingoes Canis familiaris dingo for conservation

ABSTRACT The conservation status of the dingo Canis familiaris dingo is threatened by hybridization with the domestic dog C. familiaris familiaris. A practical method that can estimate the different levels of hybridization in the field is urgently required so that animals below a specific threshold of dingo ancestry (e.g. 1/4 or 1/2 dingoes) can reliably be identified and removed from dingo populations. Skull morphology has been traditionally used to assess dingo purity, but this method does not discriminate between the different levels of dingo ancestry in hybrids. Furthermore, measurements can only be reliably taken from the skulls of dead animals. Methods based on the analysis of variation in DNA are able to discriminate between the different levels of hybridization, but the validity of this method has been questioned because the materials currently used as a reference for dingoes are from captive animals of unproven genetic purity. The use of pre‐European materials would improve the accuracy of this method, but suitable material has not been found in sufficient quantity to develop a reliable reference population. Furthermore, current methods based on DNA are impractical for the field‐based discrimination of hybrids because samples require laboratory analysis. Coat colour has also been used to estimate the extent of hybridization and is possibly the most practical method to apply in the field. However, this method may not be as powerful as genetic or morphological analyses because some hybrids (e.g. Australian cattle dog × dingo) are similar to dingoes in coat colour and body form. This problem may be alleviated by using additional visual characteristics such as the presence/absence of ticking and white markings.

Dingoes on Fraser Island—Tourism Dream or Management Nightmare

Fraser Island is a unique tourist destination catering to more than 300,000 visitors annually. A significant attraction of the World Heritage-listed island are the dingoes, which are regarded as one of the purest strains in Australia. The dingo population is estimated to be between 150 and 200 animals and their conservation is of national significance. Concerns have long been expressed about the potential for dangerous interactions between dingoes and humans. As visitation to the Island has increased, aspects of the environment have changed and dingoes have altered their normal habits. Management practices have focussed on removing unnatural food sources, such as open rubbish dumps, and educating the public. On April 30, 2001, dingoes mauled a 9-year-old boy to death and the public demanded firm management decisions. However, the fundamental question remained. Do we manage the animals or the people? Public opinion was polarised. This article describes the issues and politics of managing dingoes and tourists on Fraser Island, and highlights how a single serious incident can influence management decisions.

The diets of cats, foxes and dingoes in relation to prey availability in the Tanami Desert, Northern Territory

In most areas of Australia, mammals constitute the staple diets of cats, foxes and dingoes. In central Australia the abundance of mammals is often too low to meet the dietary requirements of these carnivores and yet populations of cats, foxes and dingoes persist. To investigate alternative feeding strategies of cats, foxes and dingoes in arid environments, their diets were monitored in relation to prey availability in two areas of the Tanami Desert where rabbits do not occur. Dietary information was obtained by analysing predator scats collected between 1995 and 1997. Prey availability was monitored by track counts, pitfall trapping, Elliott trapping, and bird counts along walked transects. In contrast to dietary studies elsewhere in Australia, it was found that reptiles were an important component of the diets of predators in the Tanami Desert, and should be classified as seasonal staples. Birds increased in importance in the diets of cats and foxes during the winter, when reptiles were less active. There was considerable overlap between the diets of all three predators, although dingoes ate more large prey items (e.g.�macropods) than the other two predators. Results highlight the opportunistic feeding habits of cats, foxes and dingoes and show that, although mammalian prey are less important in central Australia than has been found elsewhere, species that are vulnerable to extinction, such as the bilby (Macrotis lagotis), mulgara (Dasycercus cristicauda) and marsupial mole (Notoryctes typhlops), are also consumed by these predators.

Parasites of the bridled nailtail wallaby (Onychogalea fraenata) (Marsupialia : Macropodidae)

The bridled nailtail wallaby (Onychogalea fraenata), an endangered macropod, has been reintroduced into the wild after a captive-breeding program. As part of a management program to assess the risks to its survival O. fraenata were trapped and examined for ecto- and endoparasites. From February to September 1996, 55 wallabies from Taunton National Park, central Queensland, some trapped more than once, were visually examined for ectoparasites. The blood of 39 O. fraenata was tested for antibodies against Toxoplasma gondii and Echinococcus granulosus and a total of 82 faecal samples were examined microscopically. In addition, in a second study a complete carcase, three complete gastro-intestinal tracts, and a single stomach, obtained from various sources, including Idalia National Park, were examined for helminth parasites. The most prevalent ectoparasites were the ticksAmbylomma triguttatum and Haemaphysalis bancrofti. Other ectoparasites included four species of trombiculid mites and a louse, Heterodoxus sp. A single instance of the nippoboscid fly, Ortholfersia minuta, was found. From the serological surveys, antibodies against Toxoplasma and Echinococcus were detected in 15% and 21% respectively. No trematode or cestode eggs or protozoal cysts were found in faeces. Nematode eggs had a prevalence of 92% with a mean egg density of 500 eggs per gram. Strongyloides sp. (larvae) was the most prevalent nematode in faeces. In the postmortem study, seven nematode species (Cloacina polyxo, Hypodontus macropi, Labiostrongylus onychogale, Macropostrongyloides baylisi, Macropoxyuris sp., Rugopharynx australis and Zoniolaimus buccalis) and four cestode species (Progamotaenia bancrofti, P. zschokkei, P. abietiformis and larval E. granulosus) were found. Six of the nematode species are new host records. The presence of infection with the introduced parasites T. gondii and E. granulosus, both recognised as serious pathogens, is of management significance. Since the definitive hosts of these parasites are cats and canids respectively, control of cat, dog and dingo populations within the Park will lessen the incidence of infection with these parasites.

Measuring predator control effectiveness: reducing numbers may not reduce predator impact

Author(s): Allen, Lee | Abstract: The fundamental assumption in the management of predators is that reducing predator numbers will reduce their predation impact on livestock. Research on dingoes (Canis lupus dingo) has shown this assumption to be incorrect in beef production areas in northern and western Queensland. Aerial and ground baiting with 1080 (fluoroacetate) is the principal dingo-control method used in extensive pastoral areas of Australia. This paper compares four approaches to measure the effectiveness of these control programs. Dingo abundance was reduced in 11 of 13 baiting campaigns monitored with almost two-thirds of these producing g50% reduction. However, concurrent decline in dingo abundance occurred in non-baited areas due to seasonal changes in dingo populations. When this was taken into account, less than half of the control programs produced g50% reduction. The time taken for dingoes to recolonize baited areas is also an important measure of effectiveness. In two-thirds of the control programs, conducted in the first nine months of the year, dingoes recolonized prior to the period of peak calving (November/December) when the biggest threat to calves existed. The timing and the scale of control programs affect the rate of re-colonization. Calf loss was subsequently higher and occurred more frequently in baited areas compared to non-baited areas. Seasonal conditions, the status of prey populations, and the impact of control programs on social organization and prey selection, are key factors affecting calf predation. Control programs should be assessed by measuring impact rather than changes in predator numbers. The assumption that a direct relationship exists between predator numbers and impact is not valid for dingoes in beef production areas in northern Australia.

Population indices for wild carnivores: a critical study in sand-dune habitat, south-western Queensland

Populations of feral cats, foxes and dingoes were assessed at four sites in the northern Simpson Desert from May 1995 to October 1996 using track counts. Counts were based on presence/absence of footprints on sandplots placed randomly throughout each of the four sites, with all habitats being sampled in accordance with their availability. Sandplots were repositioned between sampling periods so that data were temporally independent. This unbiased method was used to assess the reliability of more conventional indices of carnivore abundance based on spotlighting and counts of footprints on roads, which were run concurrently with the random sandplot counts. The sandplot data were also used to assess habitat use of the three study species. Counts on regularly spaced sampling plots along roads were correlated with random sandplot counts for foxes, but not for cats. Conversely, an index of activity based on counting individual tracks along roads was correlated for cats, but not for foxes. Spotlighting counts appeared to have little relationship with random sandplot counts for either species, with random sandplot counts and spotlight counts of foxes being correlated for only one of the four sites and no correlations being apparent for cats. The sandplot data showed that cats used dune crests preferentially over other habitats, while foxes preferred both dune crests and roads. Dune crests are probably used as natural runways by both species. Dingoes used roads preferentially over other habitats. It was concluded that differences in the use of roads and other runways by the carnivores can potentially lead to biases in indices collected along roadways. In relation to the random sandplot counts, foxes were overestimated by road counts and spotlighting relative to cats, the latter bias being related possibly to temporal differences in the activity patterns of the two species.

Evaluation of three relative abundance indices for assessing dingo populations

Three methods of assessing relative abundance of wild canids were evaluated on a population of dingoes, Canis lupus dingo (Corbett), on a cattle station in south-westem Queensland. The tested indices relied on measurements of activity based on spoor. Two of the techniques attracted the target species to tracking stations through the use of a novel (fatty acid scent) or food-based (buried meat) attractant. The third index (activity) measured the number of dingo tracks crossing tracking stations placed at 1-km intervals along a road transect. All three indices had a high level of agreement for detecting differences in relative abundance, with correlation coefficients exceeding 0.85. When the stations were analysed in 1-km segments, the activity index proved the most sensitive, producing proportionally more positive responses than either of the other two indices irrespective of whether the tracking stations were assessed at 1-, 2-, 3- or 4-day intervals. Inconsistencies between indices existed, with the derived abundance indices not showing the anticipated reduction following population reduction. The effect of season and the interaction between dingo activity and index methodology are discussed.

V. Human Predation on The Dingo

The scalp bonus certificates of 18 614 dingoes destroyed on the mid-north coast of NSW between 1958 and 1983 were examined. Annual scalp returns were highest in 1961 (1546), fell to 256 by 1974 then rose to 475 by 1983. The decline was associated more with a reduction in the area from which dingoes were taken rather than a reduced offtake from the overall area. Half the dingoes were taken by trapping and 37% were shot, although shooting, which was more opportunistic than trapping, became relatively more common during the period. The sex ratio of the dingoes killed was strongly biased towards males but there was evidence that this reflected the sex ratio in the dingo population. We suggest that the bias arose from higher natural mortality of female pups associated with their smaller size.The number of hunters declined during the study. On average, each operated for 2.3 years (range 1-22) and killed 6.4 dingoes (range 1-231). A small group of hunters made a significant contribution to the total scalp take over time and there was some evidence of harvesting amongst this group. Two-thirds of the scalps were taken by property owners or their relatives and only 22% by hunters with no obvious association with the land on which they hunted. Because of this and the lack of any relationship between the cash value of the bonus and scalp returns, the value of the bonus system as an incentive to control dingoes is questionable.

The Effectiveness of Aerial Baiting for the Control of Dingoes in North-Western Australia

Radiotracking was used to evaluate the effectiveness of aerial baiting in controlling populations of wild dingoes, Canisfamiliaris dingo. Four baitings were carried out in the West Pilbara region of Western Australia, using fresh-meat baits or factory-produced baits, poisoned with compound 1080. In one trial fresh-meat baits killed all 18 radio-collared dingoes; in another, factory baits killed 63% of radio-collared dingoes; in a third, 62% were killed by factory and fresh-meat baits. The factors considered to be most important in influencing the results of these trials included the number and distribution of baits dropped, bait type, and the age and social status of dingoes. Aerial baiting was shown to be an efficient and cost-effective dingo control technique under the conditions existing during the study. The long-term effects on the dingo population are discussed.

The Ecology of the Dingo in North-Eastern New South Wales. 2. Diet.

The diet of two populations of dingoes, from adjacent areas different in topography and altitude, from 1969 to 1974, were similar. The remains of native mammals were found in over 90% of the scats, and Wallabia bicolor was the most important single prey species in both areas. The high frequency of large native species in this and other studies of dingoes' diet suggested that dingoes may be essentially predators of the larger native species. The mammalian composition of the diet varied significantly between May-October and November-April; this reflected a change in the hunting strategy ofthe dingo, as an outcome of behavioural necessity rather than a change in the relative abundances of prey species. Concurrent with an increase in the dingo population, the composition of the diet changed between 1972 and 1974, with an increased concentration on larger prey species in the later years; this also indicated a change in hunting strategy. Large prey species provide potentially more biomass per unit kill; and this change in hunting strategy may be a behavioural mechanism for buffering dingo populations against either increases in their own population or decreases in those of their prey.

Distribution and Population Dynamics of Dingoes (Canis familiaris) and Feral Pigs (Sus scrofa) in Queensland, 1945-1976

Both species are widespread in Queensland but there is evidence of increased numbers and a wider distribution of feral pigs in the latter part of the survey period, associated with reduced numbers of dingoes following a sodium monofluoroacetate (1080') poisoning campaign. Dingoes and, more particularly, feral pigs showed indications of delayed density-dependent mortality. The causes of mortality in dingo populations include social restrictions on breeding. Mortality of feral pigs was significantly related to dingo numbers (predation) and to rainfall (food supply). Variation in annual rainfall had a more pronounced effect on feral pig mortality in areas of low rainfall than in areas of higher rainfall. -from Author

The Diet of the Dingo in Western Australia.

Between 1971 and 1976, 160 stomachs of dingo [Canis dingo] were collected from rangeland of Western Australia, with conditions ranging from those of arid Nullarbor to tropical Kimberley. There were 14 empty stomachs. In the other stomachs, mammals were the main food by percentage of number and volume. The main mammal foods were macropods, mainly red kangaroo (Megaleia rufa) and euro (Macropus robustus), which together were over 70% by volume of food and occurred in over 65% of stomachs. There were small amounts of domestic sheep, cattle or goats and some food had been eaten as carrion, probably including one sheep that had been shot. Birds provided small volume but were found in 15% of stomachs; the main bird was emu (Dromaius novaehollandiae). Small mammals, reptiles and insects were found and grasshoppers or locusts may be an important food during plagues of those insects. Where rabbits occurred they were a large part of the diet and dingo population may fluctuate in response to changes in rabbit population. Dingos seemed to be opportunistic feeders and to prefer wild animals to domestic stock even though those were usually equally available.