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Variation in aboveground cover influences soil nitrogen availability at fine spatial scales following severe fire in subalpine conifer forests

Author(s): Monica G. Turner, William H. Romme, Erica A. H. Smithwick, Daniel B. Tinker, Jun Zhu
Year Published: 2011
Description:

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.

Citation: Turner, Monica G.; Romme, William H.; Smithwick, Erica A. H.; Tinker, Daniel B.; Zhu, Jun. 2011. Variation in aboveground cover influences soil nitrogen availability at fine spatial scales following severe fire in subalpine conifer forests. Ecosystems. 14(7): 1081-1095.
Topic(s): Fire Effects, Ecological - First Order, Soil Heating, Ecological - Second Order, Vegetation
Ecosystem(s): Subalpine wet spruce-fir forest, Subalpine dry spruce-fir forest
Document Type: Book or Chapter or Journal Article
NRFSN number: 12031
FRAMES RCS number: 16100
Record updated: Mar 22, 2018