Oxygen and Carbon Isotope Variations in a Modern Rodent Community – Implications for

Background: The oxygen (d18O) and carbon (d13C) isotope compositions of bioapatite from skeletal remains of fossil mammals are well-established proxies for the reconstruction of palaeoenvironmental and palaeoclimatic conditions. Stable isotope studies of modern analogues are an important prerequisite for such reconstructions from fossil mammal remains. While numerous studies have investigated modern large- and medium-sized mammals, comparable studies are rare for small mammals. Due to their high abundance in terrestrial ecosystems, short life spans and small habitat size, small mammals are good recorders of local environments. Methodology/Findings: The d18O and d13C values of teeth and bones of seven sympatric modern rodent species collected from owl pellets at a single locality were measured, and the inter-specific, intra-specific and intra-individual variations were evaluated. Minimum sample sizes to obtain reproducible population d18O means within one standard deviation were determined. These parameters are comparable to existing data from large mammals. Additionally, the fractionation between coexisting carbonate (d18OCO3) and phosphate (d 18OPO4) in rodent bioapatite was determined, and d 18O values were compared to existing calibration equations between the d18O of rodent bioapatite and local surface water (d18OLW)