Use of Atlantic Forest protected areas by free-ranging dogs: estimating abundance and persistence of use

Worldwide, domestic dogs (Canis familiaris) are one of the most common carnivoran species in natural areas and their populations are still increasing. Dogs have been shown to impact wildlife populations negatively, and their occurrence can alter the abundance, behavior, and activity patterns of native species. However, little is known about abundance and density of the free-ranging dogsthat use protected areas. Here, we used camera trapdata with an open-robust design mark–recapture modelto estimate the number of dogs that used protected areasin Brazilian Atlantic Forest. We estimated the time period these dogs used the protected areas, and explored factors that influenced the probability of continued use (e.g., season, mammal richness, proportion of forest), while accounting for variation in detection probability. Dogs in the studied system were categorized as rural free-ranging, and their abundance varied widely across protected areas(0–73 individuals). Dogs used protected areasnear human houses for longer periods (e.g., >50% of sampling occasions) compared to more distant areas. We found no evidence that their probability of continued use varied with season or mammal richness. Dog detection probability decreased linearly among occasions, possibly due to the owners confining their dogs after becoming aware of our presence. Comparing our estimates to those for native carnivoran, we found that dogs were three to 85 times more abundant than ocelots ( Leoparduspardalis), two to 25 times more abundant than puma( Pumaconcolor), and approximately five times more abundant than the crab-eating fox( Cerdocyon thous). Combining camera trappingdata with modern mark–recapture methods provides important demographic information on free-ranging dogsthat can guide management strategies to directly control dogs' abundance and ranging behavior.