Nitrogen isotope signature variability in plant species from open peatland

We report natural abundance of 15N content in a suite of plants and lichens from a sloping open peatland in coastal northern British Columbia, Canada. A wide range of δ15N values varying between −11 and +3‰ were observed in the studied species. Herbs, mosses, and shrubs generally grouped individually along the δ15N gradient from enriched to more depleted values. This grouping probably reflects similar nitrogen acquiring strategies within the group, but some species with different strategies showed deviated δ15N values from the cluster. Hummock-lawn gradient, which is illustrated as depth to water table, explains the variation in δ15N signature of cryptogams: the deeper the groundwater table, the more depleted is the 15N. This trend might be explained by differences in nitrogen sources and/or differences in internal fractionation during nitrogen translocation processes.