Nitrogen isotope signature variability in plant species from open peatland

We report natural abundance of (15)N content in a suite of plants and lichens from a sloping open peatland in coastal northern British Columbia, Canada. A wide range of delta(15)N values varying between -11 and +3 parts per thousand were observed in the studied species. Herbs, mosses, and shrubs generally grouped individually along the delta(15)N 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 delta(15)N values from the cluster. Hummock-lawn gradient, which is illustrated as depth to water table, explains the variation in delta(15)N signature of cryptogams: the deeper the groundwater table, the more depleted is the (15)N. This trend might be explained by differences in nitrogen sources and/or differences in internal fractionation during nitrogen translocation processes. (c) 2005 Elsevier B.V. All rights reserved.