| 项目编号: | 1630360
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| 项目名称: | Riparian shrub expansion: Linkages to permafrost, hydrology and soil microbes |
| 作者: | Anna Liljedahl
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| 承担单位: | University of Alaska Fairbanks Campus
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| 批准年: | 2016
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| 开始日期: | 2016-07-01
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| 结束日期: | 2017-06-30
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| 资助金额: | 61913
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| 资助来源: | US-NSF
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| 项目类别: | Standard Grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Geosciences - Polar
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| 英文关键词: | tall shrub
; permafrost
; shrub recruitment
; widespread permafrost degradation
; soil microbial community
; stream
; shrub height
; recent arctic shrub expansion
; arctic shrub cover
; permafrost-free ground
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| 英文摘要: | The climatic drivers and landscape-scale patterns of recent Arctic shrub expansion are well understood, while the biogeochemical and physical mechanisms controlling shrub recruitment and growth remain unclear. The biogeophysical characteristics associated with tall shrub expansion near streams could potentially explain the documented increases in carbon and nutrient export from large Arctic rivers through the underlying processes of widespread permafrost degradation and increased subsurface flow. Additionally, occurrences of tall shrubs could be used as a readily measured proxy for subsurface properties both across space and time using remote sensing. If our observations hold true in other stream environments, the information has the potential to provide novel hydrological, permafrost, and biological process insights to complement the extensive literature on increasing Arctic shrub cover. Preliminary measurements of differential runoff in Arctic tundra link tall shrubs along riparian corridors to losing stream sections (streams with decreasing discharge downstream), whereas gaining or maintaining stream sections (increasing discharge downstream) lack tall shrubs.
This award will support measurements to test whether the formation of a talik (permafrost-free ground) and a downward hydrologic gradient creates a biogeochemical subsurface environment that favors shrub recruitment and growth, which, in turn, results in patterns of tall shrub distribution coinciding along losing stream reaches. This team will measure additional streams with differing gradients, bed morphologies, and substrates to test the statistical significance of their preliminary observation that tall shrubs indicate losing streams, and to expand measurements to include shrub height, cover, biomass, Leaf Area Index (LAI), permafrost, and soil microbial communities.
The award will support three early career researchers to gather background data to enable them to explore a potentially transformative idea to set the foundation to examine the processes linking shrubs, permafrost, hydrology and microbiology. The results of this work would be disseminated directly to land management and private organizations. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/91996
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| Appears in Collections: | 全球变化的国际研究计划
科学计划与规划
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| Recommended Citation: | |
Anna Liljedahl. Riparian shrub expansion: Linkages to permafrost, hydrology and soil microbes. 2016-01-01.
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