Domestic dogs as invasive species: from local to global impacts

Abstract

Domestic dogs are the most abundant carnivores worldwide. Food and othersubsidies to dogs do not prevent their predation on wildlife. Dog impacts on wildlife are suspected to be significant, yet the nature of dog-wildlife interactions is not fully understood. In this context I addressed three specific objectives. First, I tested the hypothesis that the distribution of dogs influences the space use of potential prey.This hypothesis was tested using as target species the southern pudu (Pudu puda), a globally vulnerable deer. Second, I tested the hypothesis that the management of domestic dogs and cats influences their impacts on wild vertebrates. Third, I assessed whether dogs are a global concern for biodiversity conservation by conducting a broad literatura review.The study conducted on pudus in Chile revealed that dogs are frequent andefficient predators of this species. In occupancy models applied to camera-trapdata, the variable that best explained the distribution of pudus was the probabilityof dog presence. The second study, confirmad that domestic dogs preyed on mostthreatened mammals present in two sites. My results provided support for the hypothesis that the less ca re domestic animals receive from owners the higher the probability those animals will prey on wildlife. Finally, the literature review showed that dogs are considered a threat for 160 mammalian species. These numbers are very similar to those observed for feral cats, one of the most damaging invasive species worldwide. The review al so revealed that the few studies on the spatial consequences of the presence of dogs converge in suggesting that they are athreat for groups such as Carnivores and Artiodactyls.M y findings suggest that dogs are efficient predators for species such as the pudu, and that these predation events may have consequences for the distribution of these species. Considering the potentially large number of species affected by dogs, and the fact that the impacts of dogs depend especially on human factors, I discuss the role of dog management to reduce their impacts.