Biogeochemistry

, Volume 80, Issue 2, pp 143–171

Regional Assessment of N Saturation using Foliar and Root \(\varvec {\delta}^{\bf 15}{\bf N}\)

  • L. H. Pardo
  • P. H. Templer
  • C. L. Goodale
  • S. Duke
  • P. M. Groffman
  • M. B. Adams
  • P. Boeckx
  • J. Boggs
  • J. Campbell
  • B. Colman
  • J. Compton
  • B. Emmett
  • P. Gundersen
  • J. Kjønaas
  • G. Lovett
  • M. Mack
  • A. Magill
  • M. Mbila
  • M. J. Mitchell
  • G. McGee
  • S. McNulty
  • K. Nadelhoffer
  • S. Ollinger
  • D. Ross
  • H. Rueth
  • L. Rustad
  • P. Schaberg
  • S. Schiff
  • P. Schleppi
  • J. Spoelstra
  • W. Wessel
Article

Abstract

N saturation induced by atmospheric N deposition can have serious consequences for forest health in many regions. In order to evaluate whether foliar \(\delta^{15}\hbox{N}\) may be a robust, regional-scale measure of the onset of N saturation in forest ecosystems, we assembled a large dataset on atmospheric N deposition, foliar and root \(\delta^{15}\hbox{N}\) and N concentration, soil C:N, mineralization and nitrification. The dataset included sites in northeastern North America, Colorado, Alaska, southern Chile and Europe. Local drivers of N cycling (net nitrification and mineralization, and forest floor and soil C:N) were more closely coupled with foliar \(\delta^{15}\hbox{N}\) than the regional driver of N deposition. Foliar \(\delta^{15}\hbox{N}\) increased non-linearly with nitrification:mineralization ratio and decreased with forest floor C:N. Foliar \(\delta^{15}\hbox{N}\) was more strongly related to nitrification rates than was foliar N concentration, but concentration was more strongly correlated with N deposition. Root \(\delta^{15}\hbox{N}\) was more tightly coupled to forest floor properties than was foliar \(\delta^{15}\hbox{N}\). We observed a pattern of decreasing foliar \(\delta^{15}\hbox{N}\) values across the following species: American beech>yellow birch>sugar maple. Other factors that affected foliar \(\delta^{15}\hbox{N}\) included species composition and climate. Relationships between foliar \(\delta^{15}\hbox{N}\) and soil variables were stronger when analyzed on a species by species basis than when many species were lumped. European sites showed distinct patterns of lower foliar \(\delta^{15}\hbox{N}\), due to the importance of ammonium deposition in this region. Our results suggest that examining \(\delta^{15}\hbox{N}\) values of foliage may improve understanding of how forests respond to the cascading effects of N deposition.

Keywords

15Fine roots Forests N deposition Natural abundance 

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Copyright information

© Springer 2006

Authors and Affiliations

  • L. H. Pardo
    • 1
  • P. H. Templer
    • 2
  • C. L. Goodale
    • 3
  • S. Duke
    • 4
  • P. M. Groffman
    • 5
  • M. B. Adams
    • 6
  • P. Boeckx
    • 7
  • J. Boggs
    • 8
  • J. Campbell
    • 9
  • B. Colman
    • 10
  • J. Compton
    • 11
  • B. Emmett
    • 12
  • P. Gundersen
    • 13
  • J. Kjønaas
    • 14
  • G. Lovett
    • 5
  • M. Mack
    • 15
  • A. Magill
    • 16
  • M. Mbila
    • 17
  • M. J. Mitchell
    • 18
  • G. McGee
    • 18
  • S. McNulty
    • 8
  • K. Nadelhoffer
    • 19
  • S. Ollinger
    • 16
  • D. Ross
    • 20
  • H. Rueth
    • 21
  • L. Rustad
    • 9
  • P. Schaberg
    • 1
  • S. Schiff
    • 22
  • P. Schleppi
    • 23
  • J. Spoelstra
    • 22
  • W. Wessel
    • 24
  1. 1.Northeastern Research StationUSDA Forest ServiceBurlingtonUSA
  2. 2.Department of BiologyBoston UniversityBostonUSA
  3. 3.Department of Ecology & Evolutionary BiologyCornell UniversityIthacaUSA
  4. 4.Agricultural Research ServiceCollege StationUSA
  5. 5.Institute of Ecosystem StudiesMillbrookUSA
  6. 6.USDA Forest ServiceParsonsUSA
  7. 7.University of GhentGentBelgium
  8. 8.USDA Forest ServiceRaleighUSA
  9. 9.USDA Forest ServiceDurhamUSA
  10. 10.University of CaliforniaSanta BarbaraUSA
  11. 11.US Environmental Protection AgencyCorvallisUSA
  12. 12.Centre for Ecology and HydrologyBangor UK
  13. 13.Danish Centre for Forest, Landscape and PlanningHørsholmDK
  14. 14.Norwegian Forest Research InstituteAasNorway
  15. 15.University of FloridaGainesvilleUSA
  16. 16.University of New HampshireDurhamUSA
  17. 17.Alabama A&M UniversityNormalUSA
  18. 18.SUNY School of Environmental Science and ForestrySyracuseUSA
  19. 19.The University of MichiganAnn ArborUSA
  20. 20.University of VermontBurlingtonUSA
  21. 21.Grand Valley State UniversityAllendaleUSA
  22. 22.University of WaterlooWaterlooCanada
  23. 23.Swiss Federal Institute for Forest, Snow and Landscape ResearchBirmensdorfSwitzerland
  24. 24.University of AmsterdamAmsterdam NL

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