Stable carbon isotope ecology of small mammals from the Sterkfontein Valley: Implications for habitat reconstruction

摘要

AbstractCarbon isotope analyses of tooth enamel have been widely employed by paleoecologists to understand past habitats. Most such studies use large- to medium-bodied mammals and exclude small taxa. However, analysis of fossil small mammals holds promise for resolving questions about past environments because these animals are often present in the fossil record (especially in South African cave sites), are diverse in dietary and habitat preference, yet have limited lifespans and home range sizes. Thus, the carbon isotope compositions of small mammal communities and/or species might reflect the composition of vegetation in local environments at fine scales.In this study, we assessed the degree to which carbon isotope compositions of small mammal tooth enamel record spatial changes in habitat in a southern African savanna environment. Modern small mammal specimens were collected from the pellet accumulations of three barn owl (Tyto alba africanus) roosts located within microhabitats varying from open grassland to mixed woodland. We examined rodent carbon isotope compositions within taxa, between taxa, and between tooth types in an effort to characterize variation within this group. We also compared rodent community δ13Cenamelcomposition between microhabitat types to evaluate how well small mammal isotope data reflect vegetation composition local to the roosts. Our analyses suggest that the relationship between small mammal community carbon isotopic means and vegetation composition is complex, but that with appropriate taxonomic control and consi