Fine-scale spatio-temporal and dietary responses of red foxes to wolf recovery in a mediterranean protected area

Preserving ecological complexity is a major goal of conservation biology. The recovery of large carnivores across Europe is expected to restore key interspecific interactions in trophic webs. Apex predators generally interfere with mesocarnivores, but facilitative interactions may occur through scavenging. Facilitative versus suppressive interactions may vary with increasing predator abundance, but information is scarce. We analysed changes in spatiotemporal and trophic behaviour of the red fox Vulpes vulpes in a prey-rich, Mediterranean protected area recently recolonized by the wolf Canis lupus, over six years from early recolonisation to the time of maximum predator expansion. Camera trapping records (n = 2619 wolf and n = 26195 fox detections) revealed a strong interspecific spatiotemporal association. Seasonal interspecific temporal overlap was high (Δ = 0.70–0.94, 0–1 scale) and increased throughout the study. A positive spatial association occurred between fox and wolf detection rates, and recurrent-event analyses supported attraction rather than avoidance. The occurrence of ungulates in the fox diet (n = 5150 analysed scats) peaked in the early recolonisation phase, but decreased with increasing wolf abundance. The wolf diet was dominated by wild ungulates and fox hair occurred in only 2 of the 2849 wolf scats. Our results emphasise complex interactions following wolf recovery, with increased foraging opportunities for foxes, and association prevailing over avoidance. However, benefits decreased with increasing wolf abundance, suggesting a lesser availability of leftovers for scavengers. Overall, our results indicate the restoration of the ecological role of apex predators in a prey-rich area, as well as the importance of prey availability to reduce competitive interactions.