Dog invasion in agroforests: The importance of households, roads and dog population size in the surroundings

Dogs are considered an invasive species, whose presence in natural habitats adversely affects wildlife. We investigate the effects of household and road proximity, and of dog population size in the surroundings on the invasion of cacao agroforest by dogs, and evaluate if dogs raised in the vicinity are more likely to invade agroforests than dogs of unknown origin. The study was conducted in a landscape dominated by agroforests, within the cacao growing region of Southern Bahia, Brazil. Dogs were recorded by camera-traps in 15 agroforest sites, and we identified dogs inhabiting the vicinity of each sampled agroforest site by visiting all households up to 800 m from sampling sites. We obtained 115 photographic records of 47 individuals, and identified 213 dogs inhabiting the site surroundings. The number of individuals and frequency of visit of dogs tend to be higher in agroforests located nearer a household, but were not associated with the distance to the nearest road or the dog population size in the surroundings. The frequency of visits in agroforests did not differ between dogs residing in the surroundings and dogs of unknown origin. Our results indicate that the surroundings are not the main source of dogs invading agroforests, most likely because dogs perform long-distance movements in association to humans. Strategies to reduce the impacts of dogs on wildlife will gain from studies on movement ecology and should include practices to restrict dogs’ home range.