Variation in Aboveground Cover Influences Soil Nitrogen Availability at Fine Spatial Scales Following Severe Fire in Subalpine Conifer Forests

Monica G. Turner, William H. Romme, Erica A.H. Smithwick, Daniel B. Tinker, Jun Zhu

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Following fire, fine-scale variation in early successional vegetation and soil nutrients may influence development of ecosystem structure and function. We studied conifer forests burned by stand-replacing wildfire in Greater Yellowstone (Wyoming, USA) to address two questions: (1) How do the variability and spatial structure of aboveground cover and soil nitrogen availability change during the first 4 years following stand-replacing fire? (2) At fine scales (2-20 m), are postfire soil inorganic N pools and fluxes related to aboveground cover? Aboveground cover, soil N pools, and annual net N transformations were measured from 2001 to 2004 using a spatially explicit sampling design in four 0.25-ha plots that burned during summer 2000. Within-stand variability (coefficient of variation) in postfire live vegetative cover declined with time since fire, whereas variability in bare mineral soil, charred litter and fresh litter was greatest 2-3 years postfire. The soil nitrate pool was more variable than the soil ammonium pool, but annual net nitrification was less variable than annual net N mineralization. Spatial structure (quantified by semivariograms) was observed in some aboveground cover variables (for example, graminoids and fresh litter), but there was little spatial structure in soil N variables and no obvious congruence in spatial scales of autocorrelation for soil N and aboveground cover. Significant Spearman correlations (at the sample point) indicated that aboveground cover and soil N were coupled following severe fire, and the dominant influence was from aboveground cover to soil N, rather than from soil N to vegetation. Initial patterns of fire severity and re-vegetation contributed to fine-scale heterogeneity in soil N availability for at least 4 years after severe fire.

Original languageEnglish (US)
Pages (from-to)1081-1095
Number of pages15
JournalEcosystems
Volume14
Issue number7
DOIs
StatePublished - Nov 2011

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Environmental Chemistry
  • Ecology

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