DOI: 10.1111/gcb.14084
Scopus记录号: 2-s2.0-85042625869
论文题名: Long-term deepened snow promotes tundra evergreen shrub growth and summertime ecosystem net CO2 gain but reduces soil carbon and nutrient pools
作者: Christiansen C.T. ; Lafreniére M.J. ; Henry G.H.R. ; Grogan P.
刊名: Global Change Biology
ISSN: 13541013
出版年: 2018
卷: 24, 期: 8 起始页码: 3508
结束页码: 3525
语种: 英语
英文关键词: Arctic
; carbon cycling
; climate change
; deciduous shrub
; snowfence
; soil microbes
; vegetation changes
; winter
Scopus关键词: carbon cycle
; carbon monoxide
; climate change
; deciduous tree
; nutrient dynamics
; shrub
; snow
; soil carbon
; soil microorganism
; tundra
; winter
; Rhododendron
; Tracheophyta
英文摘要: Arctic climate warming will be primarily during winter, resulting in increased snowfall in many regions. Previous tundra research on the impacts of deepened snow has generally been of short duration. Here, we report relatively long-term (7–9 years) effects of experimentally deepened snow on plant community structure, net ecosystem CO2 exchange (NEE), and soil biogeochemistry in Canadian Low Arctic mesic shrub tundra. The snowfence treatment enhanced snow depth from 0.3 to ~1 m, increasing winter soil temperatures by ~3°C, but with no effect on summer soil temperature, moisture, or thaw depth. Nevertheless, shoot biomass of the evergreen shrub Rhododendron subarcticum was near-doubled by the snowfences, leading to a 52% increase in aboveground vascular plant biomass. Additionally, summertime NEE rates, measured in collars containing similar plant biomass across treatments, were consistently reduced ~30% in the snowfenced plots due to decreased ecosystem respiration rather than increased gross photosynthesis. Phosphate in the organic soil layer (0–10 cm depth) and nitrate in the mineral soil layer (15–25 cm depth) were substantially reduced within the snowfences (47–70 and 43%–73% reductions, respectively, across sampling times). Finally, the snowfences tended (p =.08) to reduce mineral soil layer C% by 40%, but with considerable within- and among plot variation due to cryoturbation across the landscape. These results indicate that enhanced snow accumulation is likely to further increase dominance of R. subarcticum in its favored locations, and reduce summertime respiration and soil biogeochemical pools. Since evergreens are relatively slow growing and of low stature, their increased dominance may constrain vegetation-related feedbacks to climate change. We found no evidence that deepened snow promoted deciduous shrub growth in mesic tundra, and conclude that the relatively strong R. subarcticum response to snow accumulation may explain the extensive spatial variability in observed circumpolar patterns of evergreen and deciduous shrub growth over the past 30 years. © 2018 John Wiley & Sons Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110306
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Department of Biology, Queen's University, Kingston, ON, Canada; Uni Research Climate, Bjerknes Centre for Climate Research, Bergen, Norway; Department of Geography, Queen's University, Kingston, ON, Canada; Department of Geography, University of British Columbia, Vancouver, BC, Canada
Recommended Citation:
Christiansen C.T.,Lafreniére M.J.,Henry G.H.R.,et al. Long-term deepened snow promotes tundra evergreen shrub growth and summertime ecosystem net CO2 gain but reduces soil carbon and nutrient pools[J]. Global Change Biology,2018-01-01,24(8)