Pumas, culpeo foxes, bad and good dogs. Assessing strategies to mitigate predation

The restoration of large predator populations in rural landscapes represents a wildlife management challenge worldwide. In human-dominated landscapes, disrupted ecological processes often dictate the success or failure of predation mitigation strategies. The aim of this study was to investigate sheep mortality patterns in Patagonian free-ranging sheep production systems to determine the impact of pumas ( Puma concolor ) and culpeo foxes ( Lycalopex culpaeus ). We considered the influence of socio-environmental (elevation, terrain ruggedness, NDVI, wild prey availability, European hare relative abundance, native carnivore relative abundance and distance to cities or villages) and management (state-subsidized lethal control and Livestock Guarding Dogs [LGD]) factors on the occurrence of sheep death events from five causes: Starvation-Hypothermia Complex, predation by pumas, culpeo foxes, or feral dogs ( Canis lupus familiaris ), and undetermined. We monitored sheep mortality across six commercial ranches (covering 1500 km 2 and 61,000 sheep) and used hierarchical Bayesian models to evaluate variables operating on sheep death event occurrence. We performed 139 necropsies; pumas, culpeo foxes, and domestic dogs were responsible for 25.9%, 22.3%, and 21.6% of deaths, respectively. Our work showed that (i) LGD significantly reduced sheep death occurrence due to puma predation, and (ii) the occurrence of sheep predation by culpeo foxes was directly influenced by fox relative abundance and inversely influenced by prey availability. We recommend moving beyond native carnivore eradication policies, instead allocating resources to promote LGD implementation. Finally, we urge replacing domestic dog anti-euthanasia laws with responsible ownership and population control policies.