A1 Refereed original research article in a scientific journal
Fire in lichen-rich subarctic tundra changes carbon and nitrogen cycling between ecosystem compartments but has minor effects on stocks
Authors: Heim Ramona J., Yurtaev Andrey, Bucharova Anna, Heim Wieland, Kutskir Valeriya, Knorr Klaus-Holger, Lampei Christian, Pechkin Alexandr, Schilling Dora, Sulkarnaev Farid, Hoelzel Norbert
Publisher: COPERNICUS GESELLSCHAFT MBH
Publication year: 2022
Journal:: Biogeosciences
Journal name in source: BIOGEOSCIENCES
Journal acronym: BIOGEOSCIENCES
Volume: 19
Issue: 10
First page : 2729
Last page: 2740
Number of pages: 12
ISSN: 1726-4170
eISSN: 1726-4189
DOI: https://doi.org/10.5194/bg-19-2729-2022
Web address : https://doi.org/10.5194/bg-19-2729-2022
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/175849515
Fires are predicted to increase in Arctic regions due to ongoing climate change. Tundra fires can alter carbon and nutrient cycling and release a substantial quantity of greenhouse gases with global consequences. Yet, the long-term effects of tundra fires on carbon (C) and nitrogen (N) stocks and cycling are still unclear. Here we used a space-for-time approach to investigate the long-term fire effects on C and N stocks and cycling in soil and aboveground living biomass. We collected data from three large fire scars (>44, 28, and 12 years old) and corresponding control areas and used linear mixed-effect models in a Bayesian framework to analyse long-term development of C and N stocks and cycling after fire.We found that tundra fires had no long-term effect on total C and N stocks because a major part of the stocks was located belowground in soils which were largely unaltered by fire. However, fire had a strong long-term effect on stocks in the aboveground vegetation, mainly due to the reduction in the lichen layer. Fire reduced N concentrations in graminoids and herbs on the younger fire scars, which affected respective C/N ratios and may indicate an increased post-fire competition between vascular plants. Aboveground plant biomass was depleted in C-13 in all three fire scars. In soil, the relative abundance of C-13 changed with time after fire.Our results indicate that in lichen-rich subarctic tundra ecosystems, the contribution of fires to the release of additional carbon to the atmosphere might be relatively small as soil stocks appear to be resilient within the observed time frame.
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