Can Siberian alder N-fixation offset N-loss after severe fire? Quantifying post-fire Siberian alder distribution, growth, and N-fixation in boreal Alaska
Fire severity affects both ecosystem N-loss and post-fire N-balance. Climate change is altering the fire regime of interior Alaska, although the effects on Siberian alder (Alnus viridis ssp. fruticosa) annual N-fixation input (kg N ha-1 yr-1) and ecosystem N-balance are largely unknown. We establish...
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ftrepec:oai:RePEc:plo:pone00:0238004 2023-05-15T17:58:20+02:00 Can Siberian alder N-fixation offset N-loss after severe fire? Quantifying post-fire Siberian alder distribution, growth, and N-fixation in boreal Alaska Brian Houseman Roger Ruess Teresa Hollingsworth Dave Verbyla https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0238004 https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0238004&type=printable unknown https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0238004 https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0238004&type=printable article ftrepec 2020-12-04T13:42:59Z Fire severity affects both ecosystem N-loss and post-fire N-balance. Climate change is altering the fire regime of interior Alaska, although the effects on Siberian alder (Alnus viridis ssp. fruticosa) annual N-fixation input (kg N ha-1 yr-1) and ecosystem N-balance are largely unknown. We established 263 study plots across two burn scars within the Yukon-Tanana Uplands ecoregion of interior Alaska. Siberian alder N-input was quantified by post-fire age, fire severity, and stand type. We modeled the components of Siberian alder N-input using environmental variables and fire severity within and across burn scars and estimated post-fire N-balance using N-loss (volatilized N) and N-gain [biological N-fixation and atmospheric deposition]. Mean nodule-level N-fixation rate was 70% higher 11-years post-fire (12.88 ± 1.18 μmol N g-1 hr-1) than 40-years post-fire (7.58 ± 0.59 μmol N g-1 hr-1). Structural equation modeling indicated that fire severity had a negative effect on Siberian alder density, but a positive effect on live nodule biomass (g nodule m-2 plant-1). Post-fire Siberian alder N-input was highest in 11-year old moderately burned deciduous stands (11.53 ± 0.22 kg N ha-1 yr-1), and lowest in 11-year old stands that converted from black spruce to deciduous dominance after severe fire (0.06 ± 0.003 kg N ha-1 yr-1). Over a 138-year fire return interval, N-gains in converted black spruce stands are estimated to offset 15% of volatilized N, whereas N-gains in burned deciduous stands likely exceed volatilized N by an order of magnitude. High Siberian alder density and nodule biomass drives N-input in burned deciduous stands, while low N-fixer density (including Siberian alder) limits N-input in high severity black spruce stands not underlain by permafrost. A severe fire regime that converts black spruce stands to deciduous dominance without alder recruitment may induce progressive N-losses which alter boreal forest ecosystem patterns and processes. Article in Journal/Newspaper permafrost Alaska Yukon RePEc (Research Papers in Economics) Yukon |
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RePEc (Research Papers in Economics) |
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Fire severity affects both ecosystem N-loss and post-fire N-balance. Climate change is altering the fire regime of interior Alaska, although the effects on Siberian alder (Alnus viridis ssp. fruticosa) annual N-fixation input (kg N ha-1 yr-1) and ecosystem N-balance are largely unknown. We established 263 study plots across two burn scars within the Yukon-Tanana Uplands ecoregion of interior Alaska. Siberian alder N-input was quantified by post-fire age, fire severity, and stand type. We modeled the components of Siberian alder N-input using environmental variables and fire severity within and across burn scars and estimated post-fire N-balance using N-loss (volatilized N) and N-gain [biological N-fixation and atmospheric deposition]. Mean nodule-level N-fixation rate was 70% higher 11-years post-fire (12.88 ± 1.18 μmol N g-1 hr-1) than 40-years post-fire (7.58 ± 0.59 μmol N g-1 hr-1). Structural equation modeling indicated that fire severity had a negative effect on Siberian alder density, but a positive effect on live nodule biomass (g nodule m-2 plant-1). Post-fire Siberian alder N-input was highest in 11-year old moderately burned deciduous stands (11.53 ± 0.22 kg N ha-1 yr-1), and lowest in 11-year old stands that converted from black spruce to deciduous dominance after severe fire (0.06 ± 0.003 kg N ha-1 yr-1). Over a 138-year fire return interval, N-gains in converted black spruce stands are estimated to offset 15% of volatilized N, whereas N-gains in burned deciduous stands likely exceed volatilized N by an order of magnitude. High Siberian alder density and nodule biomass drives N-input in burned deciduous stands, while low N-fixer density (including Siberian alder) limits N-input in high severity black spruce stands not underlain by permafrost. A severe fire regime that converts black spruce stands to deciduous dominance without alder recruitment may induce progressive N-losses which alter boreal forest ecosystem patterns and processes. |
format |
Article in Journal/Newspaper |
author |
Brian Houseman Roger Ruess Teresa Hollingsworth Dave Verbyla |
spellingShingle |
Brian Houseman Roger Ruess Teresa Hollingsworth Dave Verbyla Can Siberian alder N-fixation offset N-loss after severe fire? Quantifying post-fire Siberian alder distribution, growth, and N-fixation in boreal Alaska |
author_facet |
Brian Houseman Roger Ruess Teresa Hollingsworth Dave Verbyla |
author_sort |
Brian Houseman |
title |
Can Siberian alder N-fixation offset N-loss after severe fire? Quantifying post-fire Siberian alder distribution, growth, and N-fixation in boreal Alaska |
title_short |
Can Siberian alder N-fixation offset N-loss after severe fire? Quantifying post-fire Siberian alder distribution, growth, and N-fixation in boreal Alaska |
title_full |
Can Siberian alder N-fixation offset N-loss after severe fire? Quantifying post-fire Siberian alder distribution, growth, and N-fixation in boreal Alaska |
title_fullStr |
Can Siberian alder N-fixation offset N-loss after severe fire? Quantifying post-fire Siberian alder distribution, growth, and N-fixation in boreal Alaska |
title_full_unstemmed |
Can Siberian alder N-fixation offset N-loss after severe fire? Quantifying post-fire Siberian alder distribution, growth, and N-fixation in boreal Alaska |
title_sort |
can siberian alder n-fixation offset n-loss after severe fire? quantifying post-fire siberian alder distribution, growth, and n-fixation in boreal alaska |
url |
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0238004 https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0238004&type=printable |
geographic |
Yukon |
geographic_facet |
Yukon |
genre |
permafrost Alaska Yukon |
genre_facet |
permafrost Alaska Yukon |
op_relation |
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0238004 https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0238004&type=printable |
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