Impacts of Free-Ranging Dogs on a Community of Vertebrate Scavengers in a High Andean Ecosystem

Background and Research Aims: Native vertebrate scavenger communities may be affected by free-ranging dogs (Canis lupus familiaris), but little information is available on this subject. We aimed to evaluate the influence of free-ranging dogs on a community of native vertebrate scavengers and to propose management and conservation actions. Methods: Between November 2014 and June 2016, we systematically monitored 37 ungulate carcasses in the buffer zone of Antisana National Park, Andes of Ecuador at an elevation range between 3000 and 4150 m asl. We monitored carcasses with camera traps operating 24 hours per day. Results: We obtained 1010 independent events and recorded seven vertebrate scavenger species. Free-ranging dogs were present at carcasses for 40.39% of the total activity time, but the most frequently recorded species were the Andean fox (Lycalopex culpaeus) and the Carunculated Caracara (Phalcoboenus carunculatus). The scavenging birds were diurnal, the Andean fox was mostly nocturnal, and the free-ranging dogs were active in all periods of the day. Native scavenger species changed their peak of activity to times when the free-ranging dogs were less active, probably to avoid agonistic encounters. The presence of free-ranging dogs negatively influenced the number of independent events of the native species. Conclusion: The presence of free-ranging dogs showed a negative relationship with the residence time and the number of independent events of native scavenging species. Furthermore, their presence modified the hour of the peak in the activity patterns of the scavenger community. Implications for Conservation: The presence of free-ranging dogs may have important implications for the conservation of the Vulnerable Andean Condor (Vultur gryphus) in Ecuador. To achieve the conservation goals of native vertebrate scavengers, particularly of Andean Condors, it is necessary to develop environmental education programs, provide technical training in responsible dog ownership, and conduct campaigns to sterilize and control dogs.