Accelerated Nutrient Cycling and Increased Light Competition Will Lead to 21st Century Shrub Expansion in North American Arctic Tundra
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, ecosy...
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ftcdlib:oai:escholarship.org:ark:/13030/qt3128r7d5 2024-02-11T10:00:18+01:00 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 1683 - 1701 2018-05-01 application/pdf https://escholarship.org/uc/item/3128r7d5 unknown eScholarship, University of California qt3128r7d5 https://escholarship.org/uc/item/3128r7d5 public Journal of Geophysical Research Biogeosciences, vol 123, iss 5 Earth Sciences Geophysics modeling shrubification climate change Arctic carbon cycle modeling PFT dynamics nutrient cycling article 2018 ftcdlib 2024-01-15T19:06:29Z 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 ~0.35m 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. 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. Article in Journal/Newspaper Arctic Climate change Tundra Alaska University of California: eScholarship Arctic |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Earth Sciences Geophysics modeling shrubification climate change Arctic carbon cycle modeling PFT dynamics nutrient cycling |
spellingShingle |
Earth Sciences Geophysics modeling shrubification climate change Arctic carbon cycle modeling PFT dynamics nutrient cycling 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 |
Earth Sciences Geophysics modeling shrubification climate change Arctic carbon cycle modeling PFT dynamics nutrient cycling |
description |
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 ~0.35m 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. 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. |
format |
Article in Journal/Newspaper |
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 |
publisher |
eScholarship, University of California |
publishDate |
2018 |
url |
https://escholarship.org/uc/item/3128r7d5 |
op_coverage |
1683 - 1701 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Climate change Tundra Alaska |
genre_facet |
Arctic Climate change Tundra Alaska |
op_source |
Journal of Geophysical Research Biogeosciences, vol 123, iss 5 |
op_relation |
qt3128r7d5 https://escholarship.org/uc/item/3128r7d5 |
op_rights |
public |
_version_ |
1790596005467521024 |