Riparian shrub expansion: Linkages to permafrost, hydrology and soil microbes

GSTDTAP

项目编号	1630360
	Riparian shrub expansion: Linkages to permafrost, hydrology and soil microbes
	Anna Liljedahl
主持机构	University of Alaska Fairbanks Campus
项目开始年	2016
	2016-07-01
项目结束日期	2017-06-30
资助机构	US-NSF
项目类别	Standard Grant
项目经费	61913(USD)
国家	美国
语种	英语
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.
来源学科分类	Geosciences - Polar Programs
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/69707
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Anna Liljedahl.Riparian shrub expansion: Linkages to permafrost, hydrology and soil microbes.2016.