Dog–wildlife interactions across Spain suggest vulnerability in periurban areas and aquatic ecosystems

Free-ranging domestic carnivores pose important threats to wildlife, yet their impact is often underestimated. We inves- tigated the spatial distribution and environmental drivers of interactions between unleashed dogs Canis familiaris and wildlife across Spain, through a citizen-science survey, based on social network data mining and complemented by expert observations. We collected 130 verified interaction records from 2007 to 2022, covering 57 affected vertebrate species. We quantified the frequency and type of interactions (lethal outcomes, harassment, and disturbance) and tested their association with local habitat availability. Birds were the most frequently documented taxonomic group (68.99%), followed by mammals (28.68%) and reptiles (2.33%). Only 18.46% of interactions were fatal; nevertheless, our analyses suggest a possible concentration of dog–wildlife interactions in the surroundings of urban areas and aquatic ecosystems. No evidence was found that lethal outcomes were associated with either dog breed type or body size. Killing was more frequent during spring and summer, likely because wildlife is particularly vulnerable at this time and human outdoor activity increases, raising encounter rates. Our results highlight the vulnerability of biodiversity-rich periurban wetlands to disturbance by unleashed dogs, emphasising the need for targeted conservation measures, stricter leash enforcement, and public awareness initiatives