Increasing tree density accelerates stand‐level nitrogen cycling at the taiga–tundra ecotone in northeastern Siberia
Abstract As climate warms, tree density at the taiga–tundra ecotone (TTE) is expected to increase, which may intensify competition for belowground resources in this nitrogen (N)‐limited environment. To determine the impacts of increased tree density on N cycling and productivity, we examined edaphic...
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ftdoajarticles:oai:doaj.org/article:d6dc836786794f9a9704440760e69cf6 2023-05-15T15:14:14+02:00 Increasing tree density accelerates stand‐level nitrogen cycling at the taiga–tundra ecotone in northeastern Siberia Rebecca E. Hewitt Heather D. Alexander Brian Izbicki Michael M. Loranty Susan M. Natali Xanthe J. Walker Michelle C. Mack 2022-07-01T00:00:00Z https://doi.org/10.1002/ecs2.4175 https://doaj.org/article/d6dc836786794f9a9704440760e69cf6 EN eng Wiley https://doi.org/10.1002/ecs2.4175 https://doaj.org/toc/2150-8925 2150-8925 doi:10.1002/ecs2.4175 https://doaj.org/article/d6dc836786794f9a9704440760e69cf6 Ecosphere, Vol 13, Iss 7, Pp n/a-n/a (2022) Arctic boreal carbon cycling Larix cajanderi natural abundance isotopes roots Ecology QH540-549.5 article 2022 ftdoajarticles https://doi.org/10.1002/ecs2.4175 2022-12-30T23:46:23Z Abstract As climate warms, tree density at the taiga–tundra ecotone (TTE) is expected to increase, which may intensify competition for belowground resources in this nitrogen (N)‐limited environment. To determine the impacts of increased tree density on N cycling and productivity, we examined edaphic properties indicative of soil N availability along with aboveground and belowground tree‐level traits and stand characteristics related to carbon (C) and N cycling across a tree density gradient of monodominant larch (Larix cajanderi) at the TTE in far northeastern Siberia. We found no consistent evidence from soil, tree, or stand‐level N cycling characteristics of lower N availability or greater intraspecific competition for N with increased density. Active layer thickness declined, but resin‐sorbed N and soil organic layer thickness did not covary with increased tree density. There was, however, greater allocation belowground to stand‐level coarse and fine roots with increased tree density, an allocation pattern suggestive of limited soil resources. Foliar traits related to C (%C, δ13C, and resorption) were responsive to density indicating the importance of non‐nutrient resources, like light, to foliar stoichiometry. As tree density increased and individual trees had lower productivity, tree‐level N and biomass pools aboveground and belowground declined tracking decreases in N uptake, N resorption, N use efficiency, and allocation to slow cycling tissues like wood. At the stand level, our findings show high N turnover with increased N acquisition, allocation to short‐lived tissues with relatively high N content and reduced N residence time, and greater stand productivity as tree density increased. Yet, these positive relationships were curtailed at the highest tree densities. Our observations of shifts in biomass, C and N allocation, and loss aboveground, along with greater root density with increased tree density, could have strong impacts on C and N cycling and should be represented in models of TTE dynamics and ... Article in Journal/Newspaper Arctic taiga Tundra Siberia Directory of Open Access Journals: DOAJ Articles Arctic Ecosphere 13 7 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Arctic boreal carbon cycling Larix cajanderi natural abundance isotopes roots Ecology QH540-549.5 |
spellingShingle |
Arctic boreal carbon cycling Larix cajanderi natural abundance isotopes roots Ecology QH540-549.5 Rebecca E. Hewitt Heather D. Alexander Brian Izbicki Michael M. Loranty Susan M. Natali Xanthe J. Walker Michelle C. Mack Increasing tree density accelerates stand‐level nitrogen cycling at the taiga–tundra ecotone in northeastern Siberia |
topic_facet |
Arctic boreal carbon cycling Larix cajanderi natural abundance isotopes roots Ecology QH540-549.5 |
description |
Abstract As climate warms, tree density at the taiga–tundra ecotone (TTE) is expected to increase, which may intensify competition for belowground resources in this nitrogen (N)‐limited environment. To determine the impacts of increased tree density on N cycling and productivity, we examined edaphic properties indicative of soil N availability along with aboveground and belowground tree‐level traits and stand characteristics related to carbon (C) and N cycling across a tree density gradient of monodominant larch (Larix cajanderi) at the TTE in far northeastern Siberia. We found no consistent evidence from soil, tree, or stand‐level N cycling characteristics of lower N availability or greater intraspecific competition for N with increased density. Active layer thickness declined, but resin‐sorbed N and soil organic layer thickness did not covary with increased tree density. There was, however, greater allocation belowground to stand‐level coarse and fine roots with increased tree density, an allocation pattern suggestive of limited soil resources. Foliar traits related to C (%C, δ13C, and resorption) were responsive to density indicating the importance of non‐nutrient resources, like light, to foliar stoichiometry. As tree density increased and individual trees had lower productivity, tree‐level N and biomass pools aboveground and belowground declined tracking decreases in N uptake, N resorption, N use efficiency, and allocation to slow cycling tissues like wood. At the stand level, our findings show high N turnover with increased N acquisition, allocation to short‐lived tissues with relatively high N content and reduced N residence time, and greater stand productivity as tree density increased. Yet, these positive relationships were curtailed at the highest tree densities. Our observations of shifts in biomass, C and N allocation, and loss aboveground, along with greater root density with increased tree density, could have strong impacts on C and N cycling and should be represented in models of TTE dynamics and ... |
format |
Article in Journal/Newspaper |
author |
Rebecca E. Hewitt Heather D. Alexander Brian Izbicki Michael M. Loranty Susan M. Natali Xanthe J. Walker Michelle C. Mack |
author_facet |
Rebecca E. Hewitt Heather D. Alexander Brian Izbicki Michael M. Loranty Susan M. Natali Xanthe J. Walker Michelle C. Mack |
author_sort |
Rebecca E. Hewitt |
title |
Increasing tree density accelerates stand‐level nitrogen cycling at the taiga–tundra ecotone in northeastern Siberia |
title_short |
Increasing tree density accelerates stand‐level nitrogen cycling at the taiga–tundra ecotone in northeastern Siberia |
title_full |
Increasing tree density accelerates stand‐level nitrogen cycling at the taiga–tundra ecotone in northeastern Siberia |
title_fullStr |
Increasing tree density accelerates stand‐level nitrogen cycling at the taiga–tundra ecotone in northeastern Siberia |
title_full_unstemmed |
Increasing tree density accelerates stand‐level nitrogen cycling at the taiga–tundra ecotone in northeastern Siberia |
title_sort |
increasing tree density accelerates stand‐level nitrogen cycling at the taiga–tundra ecotone in northeastern siberia |
publisher |
Wiley |
publishDate |
2022 |
url |
https://doi.org/10.1002/ecs2.4175 https://doaj.org/article/d6dc836786794f9a9704440760e69cf6 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic taiga Tundra Siberia |
genre_facet |
Arctic taiga Tundra Siberia |
op_source |
Ecosphere, Vol 13, Iss 7, Pp n/a-n/a (2022) |
op_relation |
https://doi.org/10.1002/ecs2.4175 https://doaj.org/toc/2150-8925 2150-8925 doi:10.1002/ecs2.4175 https://doaj.org/article/d6dc836786794f9a9704440760e69cf6 |
op_doi |
https://doi.org/10.1002/ecs2.4175 |
container_title |
Ecosphere |
container_volume |
13 |
container_issue |
7 |
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1766344703451594752 |