title: Nitrogen cycling in an extreme hyperarid environment inferred from δ(15)N analyses of plants, soils and herbivore diet.
abstract: Climate controls on the nitrogen cycle are suggested by the negative correlation between precipitation and δ(15)N values across different ecosystems. For arid ecosystems this is unclear, as water limitation among other factors can confound this relationship. We measured herbivore feces, foliar and soil δ(15)N and δ(13)C values and chemically characterized soils (pH and elemental composition) along an elevational/climatic gradient in the Atacama Desert, northern Chile. Although very positive δ(15)N values span the entire gradient, soil δ(15)N values show a positive correlation with aridity as expected. In contrast, foliar δ(15)N values and herbivore feces show a hump-shaped relationship with elevation, suggesting that plants are using a different N source, possibly of biotic origin. Thus at the extreme limits of plant life, biotic interactions may be just as important as abiotic processes, such as climate in explaining ecosystem δ(15)N values.
authors.affiliation: Departamento de Ecología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.|Institute of Ecology and Biodiversity (IEB), Las Palmeras 3425, Ñuñoa, Santiago, Chile.|FONDAP Center for Genome Regulation and Millennium Nucleus Center for Plant Systems and Synthetic Biology. Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.
authors.forename: Francisca P
authors.initials: FP
authors.lastname: Díaz
authors.affiliation: Departamento de Ecología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.|Institute of Ecology and Biodiversity (IEB), Las Palmeras 3425, Ñuñoa, Santiago, Chile.|Laboratorio Internacional de Cambio Global, LINCGlobal PUC-CSIC.|Instituto Pirenaico de Ecología, Montañana, España.
authors.forename: Matías
authors.initials: M
authors.lastname: Frugone
authors.affiliation: FONDAP Center for Genome Regulation and Millennium Nucleus Center for Plant Systems and Synthetic Biology. Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Gutiérrez
authors.affiliation: Departamento de Ecología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.|Institute of Ecology and Biodiversity (IEB), Las Palmeras 3425, Ñuñoa, Santiago, Chile.|FONDAP Center for Genome Regulation and Millennium Nucleus Center for Plant Systems and Synthetic Biology. Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.|Laboratorio Internacional de Cambio Global, LINCGlobal PUC-CSIC.
authors.forename: Claudio
authors.initials: C
authors.lastname: Latorre
mesh_terms: D000818:Animals; D002244:Carbon / Q000032:analysis; D002677:Chile; D003889:Desert Climate; D004777:Environment; D005243:Feces / Q000737:chemistry*; D060434:Herbivory; D007553:Isotope Labeling; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D010944:Plants / Q000378:metabolism*; D012987:Soil / Q000737:chemistry*
chemical_list: D012987:Soil; D002244:Carbon; D009584:Nitrogen