Spatial variability in carbon dioxide exchange processes within wet sedge meadows in the Canadian High Arctic  

作　　者：Claire M.WRIGHT Amy C.BLASER Paul M.TREITZ Neal A.SCOTT 

机构地区：[1]Department of Geography and Planning,Queen’s University,Kingston,Ontario,Canada,K7L 3N6

出　　处：《Advances in Polar Science》2021年第1期1-19,共19页极地科学进展（英文版）

基　　金：ArcticNet NCE,the Natural Sciences and Engineering Research Council,Natural Resources Canada(Polar Continental Shelf Program);the Northern Scientific Training Program,and Queen’s University。

摘　　要：Wet sedge meadows are the most productive plant communities in the High Arctic.However,the controls on carbon dioxide(CO_(2))exchange processes within wet sedge communities-and the scale at which they operate-are poorly understood.Here,the factors controlling CO_(2)exchange of wet sedge meadows experiencing different moisture regimes are examined.Environmental data are used to create predictive models of CO_(2)exchange on multiple temporal scales.Automated chamber systems recorded CO_(2)fluxes at 30-minute intervals at wet sedge sites in the Canadian High Arctic from June to August in 2014 and 2015.Static chambers were also deployed over a larger spatial extent in 2014.Our results show that wet sedge communities were strong CO_(2)sinks during the growing season(−7.67 to−44.36 g C·m^(−2)).CO_(2)exchange rates in wetter and drier areas within wet sedge meadows differed significantly(Wilcoxon,p<0.001),suggesting that soil moisture regimes within vegetation types influence net CO_(2)balance.Random Forest models explained a significant amount of the variability in CO_(2)flux rates over time(R2=0.46 to 0.90).The models showed that the drivers of CO_(2)exchange in these communities vary temporally.Variable moisture regimes indirectly influenced CO_(2)fluxes given that they exhibit different vegetation and temperature-response characteristics.We suggest that the response of a single vegetation type to environmental changes may vary depending on microenvironment variability within that community.

关 键 词：High Arctic carbon dioxide exchange wet sedge soil moisture 

分 类 号：S812[农业科学—草业科学]