Hybridization between domesticated animals and their wild counterparts can disrupt adaptive gene combinations, reduce genetic diversity, extinguish wild populations and change ecosystem function. The dingo is a free-ranging dog that is an iconic apex predator and distributed throughout most of mainland Australia. Dingoes readily hybridize with domestic dogs, and in many Australian jurisdictions, distinct management strategies are dictated by hybrid status. Yet, the magnitude and spatial extent of domestic dog-dingo hybridization is poorly characterized. To address this, we performed a continent-wide analysis of hybridization throughout Australia based on 24 locus microsatellite DNA genotypes from 3637 free-ranging dogs. Although 46% of all free-ranging dogs were classified as pure dingoes, all regions exhibited some hybridization, and the magnitude varied substantially. The southeast of Australia was highly admixed, with 99% of animals being hybrids or feral domestic dogs, whereas only 13% of the animals from remote central Australia were hybrids. Almost all free-ranging dogs had some dingo ancestry, indicating that domestic dogs could have poor survivorship in nonurban Australian environments. Overall, wild pure dingoes remain the dominant predator over most of Australia, but the speed and extent to which hybridization has occurred in the approximately 220 years since the first introduction of domestic dogs indicate that the process may soon threaten the persistence of pure dingoes.
Dogs originated more than 14,000 BP, but the location(s) where they first arose is uncertain. The earliest archeological evidence of ancient dogs was discovered in Europe and the Middle East, some 5-7 millennia before that from Southeast Asia. However, mitochondrial DNA analyses suggest that most modern dogs derive from Southeast Asia, which has fueled the controversial hypothesis that dog domestication originated in this region despite the lack of supporting archeological evidence. We propose and investigate with Y chromosomes an alternative hypothesis for the proximate origins of dogs from Southeast Asia--a massive Neolithic expansion of dogs from this region that largely replaced more primitive dogs to the west and north. Previous attempts to test matrilineal findings with independent patrilineal markers have lacked the necessary genealogical resolution and mutation rate estimates. Here, we used Y chromosome genotypes, composed of 29 single-nucleotide polymorphism (SNPs) and 5 single tandem repeats (STRs), from 338 Australian dingoes, New Guinea singing dogs, and village dogs from Island Southeast Asia, along with modern European breed dogs, to estimate the evolutionary mutation rates of Y chromosome STRs based on calibration to the independently known age of the dingo population. Dingoes exhibited a unique haplogroup characterized by a single distinguishing SNP mutation and 14 STR haplotypes. The age of the European haplogroup was estimated to be only 1.7 times older than that of the dingo population, suggesting an origin during the Neolithic rather than the Paleolithic (as predicted by the Southeast Asian origins hypothesis). We hypothesize that isolation of Neolithic dogs from wolves in Southeast Asia was a key step accelerating their phenotypic transformation, enhancing their value in trade and as cargo, and enabling them to rapidly expand and replace more primitive dogs to the West. Our findings also suggest that dingoes could have arrived in Australia directly from Taiwan, independently of later dispersals of dogs through Thailand to Island Southeast Asia.
Context Many rare and endangered species are threatened by the effects of hybridisation with their domesticated and often numerically dominant relatives. However, factors that influence interactions between hybridising species are poorly understood, thus limiting our ability to develop ameliorative strategies. Aims Here, we identify family groups and investigate patterns of gene flow between dingoes (Canis lupus dingo) and domestic dogs (C. l. familiaris) in the Tanami Desert of central Australia. We aimed to determine whether human-provided resources facilitate hybridisation or alter typical patterns of dingo breeding and social behaviour. We also ask whether remote townships are arenas for dingo–dog hybridisation. Methods Tissue samples and morphological details were collected from dingo-like animals around two mine sites where humans provide abundant supplementary food and water. Using molecular DNA analyses, we assigned animals to population clusters, determined kinship and the numbers of family groups. Rates of hybridisation were assessed around the mines and in two nearby townships. Key results Of 142 samples from mine sites, ‘pure’ dingoes were identified genetically in 89% of cases. This predominance of dingoes was supported by our observations on coat colour and body morphology. Only 2 of 86 domestic dogs sampled at the two townships showed evidence of dingo ancestry. Around the mine sites, there were two distinct population clusters, including a large family group of 55 individuals around a refuse facility. Conclusions Where superabundant and consistent food, and reliable water, was available, dingo packs were much larger and co-existed with others, contrary to expectations derived from previous research. Dingo sociality and pack structures can therefore be altered where human-provided food and water are constantly available, and this could facilitate accelerated rates of hybridisation. Implications The development of appropriate domestic-waste management strategies should be a high priority in remote areas to ensure only normal rates of population increase by dingoes, and other canids more broadly. It will also potentially impede hybridisation rates if typical canid social and behavioural traits remain intact. Additionally, areas surrounding remote human settlements are likely arenas for accentuated dingo–domestic dog interactions and should be a target for future studies.
To investigate movements and habitat selection by wild dogs we attached satellite-linked global positioning system (GPS) units to nine wild dogs (Canis lupus dingo and Canis lupus familiaris) captured in eastern Victoria in summer 2007. Units estimated locations at 30-min intervals for the first six months and then at 480-min intervals for six more months. DNA testing revealed all these wild dogs to be related. Home ranges of males were almost three times larger than those of females (males: 124.3 km2 ± 56.3, n = 4; females: 45.2 km2 ± 17.3, n = 5) and both sexes preferred subalpine grassland, shrub or woodland at the landscape and home-range scales. Wild dogs were recorded more often than expected within 25 m of roads and less often than expected within 25 m of watercourses. Wild dogs displayed higher-velocity movements with shallow turning angles (generally forwards) that connected spatial and temporal clusters comprising slower-velocity, shorter, and sharper turning movements. One wild dog travelled 230 km in 9 days before returning to its home range and another travelled 105 km in 87 days. The home-range sizes reported in this study are much larger than previously reported in south-eastern Australia. This finding, together with previous studies, suggests that the spatial scale at which wild dog management occurs needs to be reconsidered.
Large predators can significantly impact livestock industries. In Australia, wild dogs (, and hybrids) cause economic losses of more than AUD$40M annually. Landscape-scale exclusion fencing coupled with lethal techniques is a widely practiced control method. In Western Australia, the State Barrier Fence encompasses approximately 260,000km of predominantly agricultural land, but its effectiveness in preventing wild dogs from entering the agricultural region is difficult to evaluate. We conducted a management strategy evaluation (MSE) based on spatially-explicit population models to forecast the effects of upgrades to the Western Australian State Barrier Fence and several control scenarios varying in intensity and spatial extent on wild dog populations in southwest Western Australia. The model results indicate that populations of wild dogs on both sides of the State Barrier Fence are self-sustaining and current control practices are not sufficient to effectively reduce their abundance in the agricultural region. Only when a combination of control techniques is applied on a large scale, intensively and continuously are wild dog numbers effectively controlled. This study identifies the requirement for addressing extant populations of predators within fenced areas to meet the objective of preventing wild dog expansion. This objective is only achieved when control is applied to the whole area where wild dogs are currently present within the fence plus an additional buffer of ~20 km. Our modelling focused on the use of baiting, trapping and shooting; however, we acknowledge that additional tools may also be applied. Finally, we recommend that a cost-benefit analysis be performed to evaluate the economic viability of an integrated control strategy.
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