Accelerated Nutrient Cycling and Increased Light Competition Will Lead to 21st Century Shrub Expansion in North American Arctic Tundra
We present that recent changes in species composition, and increases in shrub abundance in particular, have been reported as a result of warming in Arctic tundra. Despite these changes, the driving factors that control shrubification and its future trajectory remain uncertain. Here we used an ecosys...
Published in: | Journal of Geophysical Research: Biogeosciences |
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Online Access: | http://www.osti.gov/servlets/purl/1477289 https://www.osti.gov/biblio/1477289 https://doi.org/10.1029/2017JG004319 |
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ftosti:oai:osti.gov:1477289 2023-07-30T04:01:00+02:00 Accelerated Nutrient Cycling and Increased Light Competition Will Lead to 21st Century Shrub Expansion in North American Arctic Tundra Mekonnen, Zelalem A. Riley, William J. Grant, Robert F. 2022-05-24 application/pdf http://www.osti.gov/servlets/purl/1477289 https://www.osti.gov/biblio/1477289 https://doi.org/10.1029/2017JG004319 unknown http://www.osti.gov/servlets/purl/1477289 https://www.osti.gov/biblio/1477289 https://doi.org/10.1029/2017JG004319 doi:10.1029/2017JG004319 54 ENVIRONMENTAL SCIENCES 58 GEOSCIENCES 2022 ftosti https://doi.org/10.1029/2017JG004319 2023-07-11T09:29:29Z We present that recent changes in species composition, and increases in shrub abundance in particular, have been reported as a result of warming in Arctic tundra. Despite these changes, the driving factors that control shrubification and its future trajectory remain uncertain. Here we used an ecosystem model, ecosys, to mechanistically represent the processes controlling recent and 21st century changes in plant functional type using RCP8.5 climate forcing across North American Arctic tundra. Recent and projected warming was modeled to deepen the active layer (spatially averaged by ~0.35 m by 2100) and thereby increase nutrient availability. Shrub productivity was modeled to increase across much of the tundra, particularly in Alaska and tundra-boreal ecotones. Deciduous and evergreen shrubs increased from ~45% of total tundra ecosystem net primary productivity (NPP) in recent decades to ~70% by 2100. The increased canopy cover of shrubs reduced incoming shortwave radiation for low-lying plants, causing declines in graminoids NPP from a current 35% of tundra NPP to 18%, and declines in nonvascular plants from 20% to 12%. The faster-growing deciduous shrubs modeled with less efficient nutrient conservation dominated much of the low Arctic by 2100 where nutrient cycling became more rapid, while the slower-growing evergreen shrubs modeled with more efficient nutrient conservation dominated a wider latitudinal range that extended to the high Arctic where nutrient cycling remained slower. Lastly, we conclude that high-latitude vegetation dynamics over the 21st century will depend strongly on soil nutrient dynamics, diversity in plant traits controlling nutrient uptake and conservation, and light competition. Other/Unknown Material Arctic Tundra Alaska SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Arctic Journal of Geophysical Research: Biogeosciences 123 5 1683 1701 |
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Open Polar |
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SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
op_collection_id |
ftosti |
language |
unknown |
topic |
54 ENVIRONMENTAL SCIENCES 58 GEOSCIENCES |
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54 ENVIRONMENTAL SCIENCES 58 GEOSCIENCES Mekonnen, Zelalem A. Riley, William J. Grant, Robert F. Accelerated Nutrient Cycling and Increased Light Competition Will Lead to 21st Century Shrub Expansion in North American Arctic Tundra |
topic_facet |
54 ENVIRONMENTAL SCIENCES 58 GEOSCIENCES |
description |
We present that recent changes in species composition, and increases in shrub abundance in particular, have been reported as a result of warming in Arctic tundra. Despite these changes, the driving factors that control shrubification and its future trajectory remain uncertain. Here we used an ecosystem model, ecosys, to mechanistically represent the processes controlling recent and 21st century changes in plant functional type using RCP8.5 climate forcing across North American Arctic tundra. Recent and projected warming was modeled to deepen the active layer (spatially averaged by ~0.35 m by 2100) and thereby increase nutrient availability. Shrub productivity was modeled to increase across much of the tundra, particularly in Alaska and tundra-boreal ecotones. Deciduous and evergreen shrubs increased from ~45% of total tundra ecosystem net primary productivity (NPP) in recent decades to ~70% by 2100. The increased canopy cover of shrubs reduced incoming shortwave radiation for low-lying plants, causing declines in graminoids NPP from a current 35% of tundra NPP to 18%, and declines in nonvascular plants from 20% to 12%. The faster-growing deciduous shrubs modeled with less efficient nutrient conservation dominated much of the low Arctic by 2100 where nutrient cycling became more rapid, while the slower-growing evergreen shrubs modeled with more efficient nutrient conservation dominated a wider latitudinal range that extended to the high Arctic where nutrient cycling remained slower. Lastly, we conclude that high-latitude vegetation dynamics over the 21st century will depend strongly on soil nutrient dynamics, diversity in plant traits controlling nutrient uptake and conservation, and light competition. |
author |
Mekonnen, Zelalem A. Riley, William J. Grant, Robert F. |
author_facet |
Mekonnen, Zelalem A. Riley, William J. Grant, Robert F. |
author_sort |
Mekonnen, Zelalem A. |
title |
Accelerated Nutrient Cycling and Increased Light Competition Will Lead to 21st Century Shrub Expansion in North American Arctic Tundra |
title_short |
Accelerated Nutrient Cycling and Increased Light Competition Will Lead to 21st Century Shrub Expansion in North American Arctic Tundra |
title_full |
Accelerated Nutrient Cycling and Increased Light Competition Will Lead to 21st Century Shrub Expansion in North American Arctic Tundra |
title_fullStr |
Accelerated Nutrient Cycling and Increased Light Competition Will Lead to 21st Century Shrub Expansion in North American Arctic Tundra |
title_full_unstemmed |
Accelerated Nutrient Cycling and Increased Light Competition Will Lead to 21st Century Shrub Expansion in North American Arctic Tundra |
title_sort |
accelerated nutrient cycling and increased light competition will lead to 21st century shrub expansion in north american arctic tundra |
publishDate |
2022 |
url |
http://www.osti.gov/servlets/purl/1477289 https://www.osti.gov/biblio/1477289 https://doi.org/10.1029/2017JG004319 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Tundra Alaska |
genre_facet |
Arctic Tundra Alaska |
op_relation |
http://www.osti.gov/servlets/purl/1477289 https://www.osti.gov/biblio/1477289 https://doi.org/10.1029/2017JG004319 doi:10.1029/2017JG004319 |
op_doi |
https://doi.org/10.1029/2017JG004319 |
container_title |
Journal of Geophysical Research: Biogeosciences |
container_volume |
123 |
container_issue |
5 |
container_start_page |
1683 |
op_container_end_page |
1701 |
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1772811711504449536 |