Ecosystems

, Volume 1, Issue 5, pp 464–474

Original Articles: Differential Influence of Plant Species on Soil Nitrogen Transformations Within Moist Meadow Alpine Tundra

  • Heidemarie  Steltzer
  • William D.  Bowman

DOI: 10.1007/s100219900042

Cite this article as:
Steltzer, H. & Bowman, W. Ecosystems (1998) 1: 464. doi:10.1007/s100219900042

ABSTRACT

Plant species can influence nitrogen (N) cycling indirectly through the feedbacks of litter quality and quantity on soil N transformation rates. The goal of this research was to focus on small-scale (within-community) variation in soil N cycling associated with two community dominants of the moist meadow alpine tundra. Within this community, the small-scale patchiness of the two most abundant species (Acomastylis rossii and Deschampsia caespitosa) provides natural variation in species cover within a relatively similar microclimate, thus enabling estimation of the effects of plant species on soil N transformation rates. Monthly rates of soil N transformations were dependent on small-scale variation in both soil microclimate and species cover. The relative importance of species cover compared with soil microclimate increased for months 2 and 3 of the 3-month growing season. Growing-season net N mineralization rates were over ten times greater and nitrification rates were four times greater in Deschampsia patches than in Acomastylis patches. Variability in litter quality [carbon:nitrogen (C:N) and phenolic:N], litter quantity (aboveground and fine-root production), and soil quality (C:N) was associated with three principal components. Variability between the species in litter quality and fine-root production explained 31% of the variation in net N mineralization rates and 36% of net nitrification rates. Site variability across the landscape in aboveground production and soil C:N explained 33% of the variation in net N mineralization rates and 21% of net nitrification rates. Within the moist meadow community, the high spatial variability in soil N transformation rates was associated with differences in the dominant species' litter quality and fine-root production. Deschampsia-dominated patches consistently had greater soil N transformation rates than did Acomastylis-dominated patches across the landscape, despite site variability in soil moisture, soil C:N, and aboveground production. Plant species appear to be an important control of soil N transformation in the alpine tundra, and consequently may influence plant community structure and ecosystem function.

Key words: plant species effects; net nitrogen mineralization; net nitrification; alpine tundra; phenolics; carbon:nitrogen ratio; fine-root production.

Copyright information

© Springer-Verlag New York Inc. 1998

Authors and Affiliations

  • Heidemarie  Steltzer
    • 1
  • William D.  Bowman
    • 1
  1. 1.Mountain Research Station, Institute of Arctic and Alpine Research, and Environmental, Population, and Organismic Biology, University of Colorado, Campus Box 334, Boulder, Colorado 80309-0334, USA US