CONICET | Buscador de Institutos y Recursos Humanos

In ecologically pristine ecosystems, top-down effects of apex predators play a fundamental role in shaping trophiccascades and structuring ecosystems, but in human-modified landscapes anthropogenic effects may markedly alterthe ecological role of predators. In particular, human-provisioned food subsidies represent a serious concern for theconservation of apex predators, even though little empirical attention has been given to this aspect in assessingconservation outcomes. To assess the extent to which anthropogenic food subsidies affected feeding ecology of aprotected wolf (Canis lupus) population in a human-modified landscape, we integrated scat-analysis (n=1141 from 4packs; Jan 2005Mar 2009) and winter field inspections of Global Positioning System telemetry re-locations (n = 595clusters and 96 single locations from 5 wolves in 5 packs and 3 floaters; 20082011) of wolves living in a historicalnational park of central Italy hosting both wild prey and livestock at high densities. We revealed that livestockdominated the wolf diet (mean biomass = 63.3±14.2% SD), secondarily supplemented by wild prey (36.7±5.3%, mostlywild boar, roe deer, and red deer). During winter, we revealed a higher propensity of wolves to scavenge (72.5%; n=91feeding events) rather than killing prey, and feeding behavior was affected by prey type (i.e., domestic vs wildungulates) as the large majority of scavenged carrions (75.8%) were livestock carcasses abandoned on the groundand died for reasons different from predation. Feeding behavior was not affected by social affiliation (i.e., packmembers vs solitary wolves), indicating that pack members, even if aided by cooperative hunting, were equally likelythan solitary wolves to scavenge rather than killing prey; yet, 27.5% of winter feeding events involved predation,exclusively targeted to wild prey. Our findings indicate that large livestock carrion subsidies may strongly depresspredatory behavior in wolves, despite the occurrence of an abundant wild prey community, and have relevantecological, evolutionary and management implications. Reliance on human-provided livestock carrion subsidies likelyalters the ecological role of wolves by reducing their top-down cascading effects on the ecosystem, and this hasrelevant reflections for the conservation of wolves and other apex predators in national parks. Accordingly, we call formore strict regulations to govern livestock management and practices and argue that, at least in national parks,conservation goals of apex predators need to explicitly consider their ecological role.