Citizen science and diet analysis shed light on dog-wildlife interactions in Italy

Domestic dogs Canis familiaris may cause a range of impacts on wildlife through predation, competition, pathogen transmission, harassment and hybridisation with wolves and other wild canids, yet such effects are less known than those of other domestic species. In this work, we have combined citizen science data and information collected by scientists on the potential impact of free-ranging dogs on wildlife in Italy. Citizen science data, obtained through online surveys on social networks, consisted of pictures of wildlife killed or harassed by dogs from 2002 to 2022. Additional records were collected from articles in newspapers. We also provide the results of a diet analysis from domestic dog scats, collected in the countryside in central Italy in 1998-1999, for which we assessed prey selection by comparing consumption with availability. The citizen science survey provided 589 records: dogs attacked and killed 95 species, mostly mammals and birds, including small game species. Among species of conservation concern, dogs attacked/killed Mustela putorius and Hystrix cristata, both included in Annex IV of the Habitats Directive, and the Italian endemic Lepus corsicanus and Passer italiae. Over 90% of the attacks were caused by unleashed dogs in the presence of their owner in urban and periurban areas. The 148 dog scats analysed contained 30 prey species, mainly mammals, which made the staple of the dog diet, followed by amorphous material, most likely pet food. Remains of domestic sheep were frequent in the diet, as were hares Lepus europaeus and roe deer Capreolus capreolus among wild mammals. Wild boar Sus scrofa ranked first among the selected prey species, followed by hares, whereas roe deer and grey partridges Perdix perdix were negatively selected. The mitigation of the impact of domestic carnivores on wildlife strongly requires awareness raising to promote responsible pet ownership and strict avoidance of dogs' freeranging behaviour, especially where encounters with wildlife are most likely.