Feeding ecology of three sympatric Sorex shrew species in montane forests of Slovenia

For the understanding of shrew communities, their coexistence and competition, the knowledge of diet partitioning among sympatric shrew species is crucial. In this study, the trophic niches of three coexisting Sorex species: S. alpinus, S. araneus and S. minutus were compared for the first time. Shrews were taken from a montane forest habitat in northern Slovenia (NS). A little known species, S. alpinus, fed mostly on Insecta (50 %) and Lumbricidae (25 %), as well as Lithobiomorpha, Araneae and Opiliones. Its diet differed significantly from the diet of S. araneus and S. minutus. On the other hand, a nearly-perfect trophic niche overlap was found for S. araneus and S. minutus suggesting their great hindrance of competition for food. For comparison, S. araneus from a montane forest habitat in southern Slovenia (SS) was considered. Sorex araneus from SS fed on 15 taxa, while the shrew diets in NS habitat were half as diverse. In contrast to previous studies, the nearly-perfect overlap of trophic niches in S. araneus-S. minutus indicates that in montane forest habitat, otherwise highly competitive shrews can share trophic niches.