Genetic Monitoring of a Lethal Control Programme for Wild Canids With Complex Mating Strategies

Although mammalian carnivores are ecologically important, they also drive human-wildlife conflicts. Managing carnivores using lethal control is controversial, in part because the impact of control effort is often uncertain due to limited abundance monitoring. We used an Australian metapopulation of wild dogs as a model system to investigate the feasibility of monitoring effective population size (N e ) to detect reductions in census population size (N c ) following control. Based on microsatellite data collected over an 11-year period, we parameterised an individual-based spatial population model for wild dogs that integrated demography, genetics, random or hierarchical mating, dispersal between subpopulations and compensatory immigration.N c andN ̂ e trajectories were simulated under different proportional culling rates and genetic sampling regimes. We also used simulations without culling as null models to define 95% critical values for assessing the significance of empirical changes inN ̂ e over time. We concluded there were significant reductions (39%-62%) inN ̂ e in each subpopulation of the wild dog metapopulation, mostly likely due to control. In simulations assuming a hierarchical rather than random mating system, the impact of control onN c was weakened because reproduction by subordinate individuals increased as dominant individuals were removed, yetN ̂ e reduced following culling. Sensitivity analyses demonstrated thatN ̂ e becomes an unreliable proxy ofN c when compensatory immigration is strong and compensatory reproduction is weak, in which caseN ̂ e can increase following culling due to the immigration of new genotypes. Nonetheless, our results suggestN ̂ e can provide information about wild dogN c over sufficiently short timescales to inform management.

Male dingo urinary scents code for age class and wild dingoes respond to this information

Chemical information in canid urine has been implicated in territoriality and influences the spacing of individuals. We identified the key volatile organic compound (VOC) components in dingo (Canis lupus dingo) urine and investigated the potential role of scents in territorial spacing. VOC analysis, using headspace gas chromatography-mass spectrometry (GC-MS), demonstrated that the information in fresh urine from adult male dingoes was sufficient to allow statistical classification into age categories. Discriminant function analyses demonstrated that the relative amounts or combinations of key VOCs from pre-prime (3-4 years), prime (5-9 years), and post-prime (≥10 years) males varied between these age categories, and that scents exposed to the environment for 4 (but not 33) days could still be classified to age categories. Further, a field experiment showed that dingoes spent less time in the vicinity of prime male dingo scents than other scents. Collectively, these results indicate that age-related scent differences may be discriminable by dingoes. Previous authors have suggested the potential to use scent as a management tool for wild canids by creating an artificial territorial boundary/barrier. Our results suggest that identifying the specific signals in prime-age male scents could facilitate the development of scent-based tools for non-lethal management.

Trouble in paradise: When two species of conservation and cultural value clash, causing a management conundrum

Threatened species throughout the world are in decline due to various causes. In some cases, predators of conservation or cultural value are causing the decline of threatened prey, presenting a conservation conundrum for managers. We surveyed marine turtle nests on K'gari (formally known as Fraser Island), Australia, to investigate dingo predation of green and loggerhead turtle nests, where each of these species is of conservation value. Our monitoring revealed that 84% of nests were predated by dingoes. Only 16% of nests were not consumed by dingoes, and only 5.7% of nests were confirmed to have successfully hatched. Up to 94% of nests were consumed in some areas, and predation rates were similar across different dingo packs. Information on the available numbers of nests and dingoes in the area indicated that turtle nests alone are sufficient to support extant dingoes over the summer. These results indicate that marine turtle eggs represent a previously unquantified but important food source for dingoes on K'gari, and that turtle nests at this rookery site are under serious threat from dingoes. This research should highlight the importance of prioritising the protection of turtle nests from dingoes or risk losing the entire rookery forever in the near future.

The Physiological Conundrum That is the Domestic Dog

Across Mammalia, body size and lifespan are positively correlated. However, in domestic dogs, the opposite is true: small dogs have longer lives compared with large dogs. Here, I present literature-based data on life-history traits that may affect dog lifespan, including adaptations at the whole-organism, and organ-level. Then, I compare those same traits to wild canids. Because oxidative stress is a byproduct of aerobic metabolism, I also present data on oxidative stress in dogs that suggests that small breed dogs accumulate significantly more circulating lipid peroxidation damage compared with large breed dogs, in opposition to lifespan predictions. Further, wild canids have increased antioxidant concentrations compared with domestic dogs, which may aid in explaining why wild canids have longer lifespans than similar-sized domestic dogs. At the cellular level, I describe mechanisms that differ across size classes of dogs, including increases in aerobic metabolism with age, and increases in glycolytic metabolic rates in large breed dogs across their lifespan. To address potential interventions to extend lifespan in domestic dogs, I describe experimental alterations to cellular architecture to test the "membrane pacemaker" hypotheses of metabolism and aging. This hypothesis suggests that increased lipid unsaturation and polyunsaturated fatty acids in cell membranes can increase cellular metabolic rates and oxidative damage, leading to potential decreased longevity. I also discuss cellular metabolic changes of primary fibroblast cells isolated from domestic dogs as they are treated with commercially available drugs that are linked to lifespan and health span expansion.

Human–dingo interactions on Fraser Island: an analysis of serious incident reports

Wild predators that attack people represent a significant challenge to the management authorities charged with conserving populations whilst minimising human safety risk. Fraser Island is home to an iconic population of dingoes (Canis dingo). However, conflict stemming from negative human–dingo interactions (incidents), some resulting in serious human injury and in one case, a fatality, is an ongoing concern. In an effort to highlight important factors influencing incident dynamics, we investigated the most serious incident reports gathered by the Queensland Parks and Wildlife Service for the period 2001–15. We found a consistent pattern of incidents peaking in March/April and also July, corresponding with dingo breeding and whelping seasons (respectively). Monthly vehicle permit numbers (a proxy for visitation) were not positively correlated with incident rates, except during the breeding season. Male dingoes, particularly subadult males, featured heavily in incidents. Despite the fatality being highly publicised and the advent of copious on-site warning messages and other management interventions, serious incidents continue to occur annually, including some involving children. This suggests that risks are either not always understood, or are otherwise being ignored. While our results demonstrate that dingoes generally pose minimal risk to humans, some risk remains, particularly where poorly supervised children are concerned.