RESUMO
Darwin's fox is an opportunistic omnivorous predator native to Chile classified as endangered by the IUCN Red List. Habitat use by Darwin's foxes can be negatively affected by the presence of free-ranging dogs that range freely across native and non-native habitats and can be a source of fox mortality. The objective of this study was to analyze the isotopic similarity of Darwin's fox and sympatric free-ranging dogs in Chiloé Island to determine the impact of anthropogenic environmental alterations on wild predators. We use hair samples to characterise and compare their δ13C and δ15N values and to evaluate isotopic similarity and isotope niches overlap. A generalised linear model was used to associate the isotope value with landscape variables (forest cover and vegetation type) and distance to the nearest house. We found no significant differences in δ13C or δ15N values between foxes and dogs, and a marginally significant isotope niche overlap (59.4â %). None of the selected variables at landscape and site scale were related to isotope values. Although our study is not a probe of direct contact between foxes and free-ranging dogs, the high isotopic similarity highlights the risk of pathogen spillover from free-ranging dogs to Darwin's foxes.
Assuntos
Carbono , Cães , Animais , Isótopos de Nitrogênio , ChileRESUMO
Antibodies against Spotted Fever Group (SFG) Rickettsia and Coxiella burnetii, investigated through indirect antibody immunofluorescence tests, were detected in serum samples from 3.1% and 0% of 358 rural dogs, respectively, and in none of 32 wild foxes tested. SFG Rickettsia seropositive dogs were only detected in the Mountain Desert (8%) and the Steppe-Mediterranean (9%) regions. Exposure in the Mountain Desert, where no ticks and fleas were found on any dog, could correspond to a new SFG Rickettsia sp. recently described in soft ticks or to a related agent. Our survey confirms low endemicity in the country of C. burnetii, as observed in recent serosurveys in humans.