Stable isotope ratios (δ15n and δ13c) of syntopic shrews (Sorex)

Local species richness in shrew (Soricidae) assemblages is often high, and the mechanisms of ecological separation remain relatively unexplored. In this study, hair samples from 6 species of Sorex in 3 separate assemblages were analyzed for stable carbon (C-13/C-12) and nitrogen (N-15/N-14) isotope ratios to investigate dietary differences. At each locality, common species exhibited a broad range in delta(15)N and, to a lesser extent, delta(13)C, whereas non-overlapping signatures characterized the less abundant species. Because the naturally occurring stable isotope ratios of carbon and nitrogen vary with microenvironment and trophic level, the results support the idea that shrews achieve coexistence through resource partitioning. This study is the first to report stable isotope data on syntopic shrews and provides a direction for future research into resolving the mechanisms of ecological separation in shrew communities.