Alder Distribution and Expansion Across a Tundra Hillslope: Implications for Local N Cycling
Increases in the availability of nitrogen (N) may have consequences for plant growth and nutrient cycling in N-limited tundra plant communities. We investigated the impact alder (Alnus viridis spp. fruticosa), an N-fixing deciduous shrub, has on tundra N cycling at a hillslope located on Alaska’s Se...
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Online Access: | https://doi.org/10.3389/fpls.2019.01099 https://doaj.org/article/be039acf40fe42e6a5c401c22ce67c21 |
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ftdoajarticles:oai:doaj.org/article:be039acf40fe42e6a5c401c22ce67c21 2023-05-15T15:15:16+02:00 Alder Distribution and Expansion Across a Tundra Hillslope: Implications for Local N Cycling Verity G. Salmon Amy L. Breen Jitendra Kumar Mark J. Lara Peter E. Thornton Stan D. Wullschleger Colleen M. Iversen 2019-10-01T00:00:00Z https://doi.org/10.3389/fpls.2019.01099 https://doaj.org/article/be039acf40fe42e6a5c401c22ce67c21 EN eng Frontiers Media S.A. https://www.frontiersin.org/article/10.3389/fpls.2019.01099/full https://doaj.org/toc/1664-462X 1664-462X doi:10.3389/fpls.2019.01099 https://doaj.org/article/be039acf40fe42e6a5c401c22ce67c21 Frontiers in Plant Science, Vol 10 (2019) Alnus (alder) arctic nitrogen cycling nitrogen fixation shrub encroachment tundra Plant culture SB1-1110 article 2019 ftdoajarticles https://doi.org/10.3389/fpls.2019.01099 2022-12-31T01:36:30Z Increases in the availability of nitrogen (N) may have consequences for plant growth and nutrient cycling in N-limited tundra plant communities. We investigated the impact alder (Alnus viridis spp. fruticosa), an N-fixing deciduous shrub, has on tundra N cycling at a hillslope located on Alaska’s Seward Peninsula. We quantified N fixation using 15N2 incubations within two distinct alder communities at this site: alder shrublands located on well-drained, rocky outcroppings in the uplands and alder savannas located in water tracks along the moist toeslope of the hill. Annual N fixation rates in alder shrublands were 1.95 ± 0.68 g N m-2 year-1, leading to elevated N levels in adjacent soils and plants. Alder savannas had lower N fixation rates (0.53 ± 0.19 g N m-2 year-1), perhaps due to low phosphorus availability and poor drainage in these highly organic soil profiles underlain by permafrost. In addition to supporting higher rates of N fixation, tall-statured alder shrublands had different foliar traits than relatively short-statured alder in savannas, providing an opportunity to link N fixation to remotely-sensed variables. We were able to generate a map of the alder shrubland distribution at this site using a multi-sensor fusion approach. The change in alder shrubland distribution through time was also determined from historic aerial and satellite imagery. Analysis of historic imagery showed that the area of alder shrublands at this site has increased by 40% from 1956 to 2014. We estimate this increase in alder shrublands was associated with a 22% increase in N fixation. Our results suggest that expansion of alder shrublands has the potential to substantially alter N cycling, increase plant productivity, and redistribute C storage in upland tundra regions. An improved understanding of the consequences of N fixation within N-limited tundra plant communities will therefore be crucial for predicting the biogeochemistry of these warming ecosystems. Article in Journal/Newspaper Arctic permafrost Seward Peninsula Tundra Directory of Open Access Journals: DOAJ Articles Arctic Frontiers in Plant Science 10 |
institution |
Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Alnus (alder) arctic nitrogen cycling nitrogen fixation shrub encroachment tundra Plant culture SB1-1110 |
spellingShingle |
Alnus (alder) arctic nitrogen cycling nitrogen fixation shrub encroachment tundra Plant culture SB1-1110 Verity G. Salmon Amy L. Breen Jitendra Kumar Mark J. Lara Peter E. Thornton Stan D. Wullschleger Colleen M. Iversen Alder Distribution and Expansion Across a Tundra Hillslope: Implications for Local N Cycling |
topic_facet |
Alnus (alder) arctic nitrogen cycling nitrogen fixation shrub encroachment tundra Plant culture SB1-1110 |
description |
Increases in the availability of nitrogen (N) may have consequences for plant growth and nutrient cycling in N-limited tundra plant communities. We investigated the impact alder (Alnus viridis spp. fruticosa), an N-fixing deciduous shrub, has on tundra N cycling at a hillslope located on Alaska’s Seward Peninsula. We quantified N fixation using 15N2 incubations within two distinct alder communities at this site: alder shrublands located on well-drained, rocky outcroppings in the uplands and alder savannas located in water tracks along the moist toeslope of the hill. Annual N fixation rates in alder shrublands were 1.95 ± 0.68 g N m-2 year-1, leading to elevated N levels in adjacent soils and plants. Alder savannas had lower N fixation rates (0.53 ± 0.19 g N m-2 year-1), perhaps due to low phosphorus availability and poor drainage in these highly organic soil profiles underlain by permafrost. In addition to supporting higher rates of N fixation, tall-statured alder shrublands had different foliar traits than relatively short-statured alder in savannas, providing an opportunity to link N fixation to remotely-sensed variables. We were able to generate a map of the alder shrubland distribution at this site using a multi-sensor fusion approach. The change in alder shrubland distribution through time was also determined from historic aerial and satellite imagery. Analysis of historic imagery showed that the area of alder shrublands at this site has increased by 40% from 1956 to 2014. We estimate this increase in alder shrublands was associated with a 22% increase in N fixation. Our results suggest that expansion of alder shrublands has the potential to substantially alter N cycling, increase plant productivity, and redistribute C storage in upland tundra regions. An improved understanding of the consequences of N fixation within N-limited tundra plant communities will therefore be crucial for predicting the biogeochemistry of these warming ecosystems. |
format |
Article in Journal/Newspaper |
author |
Verity G. Salmon Amy L. Breen Jitendra Kumar Mark J. Lara Peter E. Thornton Stan D. Wullschleger Colleen M. Iversen |
author_facet |
Verity G. Salmon Amy L. Breen Jitendra Kumar Mark J. Lara Peter E. Thornton Stan D. Wullschleger Colleen M. Iversen |
author_sort |
Verity G. Salmon |
title |
Alder Distribution and Expansion Across a Tundra Hillslope: Implications for Local N Cycling |
title_short |
Alder Distribution and Expansion Across a Tundra Hillslope: Implications for Local N Cycling |
title_full |
Alder Distribution and Expansion Across a Tundra Hillslope: Implications for Local N Cycling |
title_fullStr |
Alder Distribution and Expansion Across a Tundra Hillslope: Implications for Local N Cycling |
title_full_unstemmed |
Alder Distribution and Expansion Across a Tundra Hillslope: Implications for Local N Cycling |
title_sort |
alder distribution and expansion across a tundra hillslope: implications for local n cycling |
publisher |
Frontiers Media S.A. |
publishDate |
2019 |
url |
https://doi.org/10.3389/fpls.2019.01099 https://doaj.org/article/be039acf40fe42e6a5c401c22ce67c21 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic permafrost Seward Peninsula Tundra |
genre_facet |
Arctic permafrost Seward Peninsula Tundra |
op_source |
Frontiers in Plant Science, Vol 10 (2019) |
op_relation |
https://www.frontiersin.org/article/10.3389/fpls.2019.01099/full https://doaj.org/toc/1664-462X 1664-462X doi:10.3389/fpls.2019.01099 https://doaj.org/article/be039acf40fe42e6a5c401c22ce67c21 |
op_doi |
https://doi.org/10.3389/fpls.2019.01099 |
container_title |
Frontiers in Plant Science |
container_volume |
10 |
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1766345627667529728 |