An attempt to evidence post-fire adaptation of red fox diet in a Mediterranean area

Abstract

Although fires are common in Mediterranean ecosystems, there are substantial knowledge gaps regarding post-fire shifts in animal diets, especially for carnivores. Red fox Vulpes vulpes is a generalist medium-size carnivore known to have a positive post-fire response, probably due to increased prey availability or facility to hunt. As small mammals are often one of its primary food categories, and early successional visitors of post-fire habitats, we hypothesize a change in red fox diet composition in the warm season after a fire. Hair trapping and scat collection were used to investigate selection of small mammals in a typical Mediterranean region, 3 years after a fire. The diet composition of the fox was compared with that of the fox in the same area in 1992, and with other undisturbed Mediterranean areas. Diet selection was evaluated through the Forage ratio and single resource preference tests. Red fox diet was consistent with other Mediterranean areas, with fruits and seeds, invertebrates, and small mammals being the most consumed categories. However, small mammals were consumed significantly less than in 1992, while fruits and seeds significantly more. Resource selection analysis indicated avoidance for some ground-foraging small mammals, including Crocidura spp. house mouse Mus domesticus and voles, whereas Apodemus spp. were selected. Arboreal-foraging species, e.g. red squirrel Sciurus vulgaris and garden dormouse Eliomys quercinus were used in proportion to their availability. We concluded that this mesocarnivore had high feeding plasticity and exploited various resources according to their availability and catchability. Future studies are needed to further investigate red fox and other carnivores’ food shifts after fire disturbance, including various seasons, other successional stages and competition within predator guilds.