Xu, Wenyi
- Department of Soil and Environment, Swedish University of Agricultural Sciences
- Nanjing Forestry University
Abstract
Postfire nitrogen (N) becomes increasingly important with the rising frequency of fires in arctic tundra, and climate warming is expected to accelerate plant recovery following fire. However, how plants differ in utilizing this postfire N and how their postfire N uptake responds to warming remains unknown. We conducted a fire experiment in combination with a warming treatment using open top chambers (OTCs) in an arctic heath tundra, West Greenland. We investigated the longer-term fate of two postfire N forms by tracing inorganic N (15NH4+-N and 15NO3--N) and pyrogenic N pools (PyOM-15N) and examined how postfire N was acquired by vegetation at functional group- and species-specific levels. Most postfire inorganic and pyrogenic 15N (> 67%) was lost over the 4 yr following the fire, indicating limited N fertilization effects on plant recovery. Warming increased moss aboveground biomass and thus enhanced moss uptake of PyOM-15N. By contrast, warming increased the capacity of graminoids to take up inorganic 15N (+200%), despite their unchanged aboveground biomass. Our results show that warming alters postfire N cycling by shifting the pathways through which different plant functional groups access fire-derived N, with important implications for vegetation recovery and nutrient feedbacks in a warmer, more fire-prone Arctic.
Keywords
Arctic; inorganic nitrogen; nitrogen-15 tracing; pyrogenic organic matter; shrub species; tundra fire; warming
Published in
New Phytologist
2026
Publisher: WILEY
SLU Authors
UKÄ Subject classification
Botany
Publication identifier
- DOI: https://doi.org/10.1111/nph.71047
Permanent link to this page (URI)
https://res.slu.se/id/publ/146476