干旱区生态环境知识资源中心(Arid): 科尔沁草甸生态系统水分利用效率及影响因素

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	科尔沁草甸生态系统水分利用效率及影响因素
其他题名	Water use efficiency and its influential factor over Horqin Meadow
	李辉东; 关德新; 袁凤辉; 王安志; 金昌杰; 吴家兵; 李峥; 井艳丽
来源期刊	生态学报
ISSN	1000-0933
出版年	2015
卷号	35 期号:2 页码:478-488
中文摘要	生态系统水分利用效率(WUE)是衡量碳水循环耦合程度的重要指标。利用科尔沁温带草甸草地碳水通量观测数据,对该生态系统总初级生产力水分利用效率(WUE_(GPP))的日季变化规律及对环境和生理因子的响应进行分析。结果表明:(1) WUE_(GPP)日变化呈下降-稳定-上升的变化趋势,最大值出现在日出后1-2 h,阴天条件下WUE_(GPP)高于晴天,生长中期WUE_(GPP)高于生长初期和末期;(2)总初级生产力、总蒸散和WUE_(GPP)季节变化均呈夏季高、春秋低的形式,生长季平均值分别为0.57 mg m~(-2) s~(-1)、0.08 g m~(-2) s~(-1)和5.97 mg/g,最大值分别为1.49 mg m~(-2) s~(-1)、0.16 g m~(-2) s~1和13.62 mg/g;(3)总初级生产力与饱和差、气温和叶面积指数均呈二次曲线关系,与冠层导度呈对数曲线关系;总蒸散与气温呈二次曲线关系,与饱和差、叶面积指数和冠层导度相关性均不显著;(4)WUE_(GPP)与饱和差、气温和叶面积指数均呈二次曲线关系,与冠层导度呈对数曲线关系,饱和差、冠层导度和叶面积指数分别为2.0 kPa、0.0015 m/s和4.2是控制WUE_(GPP)增加的阈值;(5)净生态系统生产力水分利用效率(WUE_(NEP))和净初级生产力水分利用效率(WUE_(NPP))季节变化规律与WUE_(GPP)致,均值分别为3.47和5.47 mg/g。
英文摘要	At ecosystem level,water use efficiency (WUE,defined as the net carbon uptake per amount of water lost from the ecosystem) reflects the coupling of carbon and water cycles. Continuous observation of carbon and water fluxes was made over Horqin Meadow with eddy covariance system in growing season of 2012. This paper calculated the water use efficiency, WUE_(GPP), defined as the ratio of gross primary productivity, GPP, to evapotranspiration, ET. Diurnal and seasonal variation of WUE_(GPP) and its response to environmental and physiological factors were analyzed. The results showed that the diurnal variation of WUE_(GPP) presented a trend of decreasing-stable-increasing,and the appearance of maximum was one or two hours later after sunrise. WUE_(GPP) on cloudy day was greater than that on sunny day, and the WUE_(GPP) at the mid of the growing season was greater than that in the beginning and at the end of the growing season. Seasonal variation of GPP and ET both presented a trend of higher in summer and lower in spring and autumn. Their maximum values appeared at the end of June and in mid-July, and were 1.49 mg m~(-2) s~(-1) and 0.16 g m~(-2) s~1,respectively. Because of harvest, GPP and ET decreased rapidly around September 1st. The seasonal averaged GPP and ET were 0.57 mg m~(-2) s~(-1) and 0.08 g m~(-2) s~1 respectively. Seasonal variation of WUE_(GPP) also presented a trend of higher in summer and lower in spring and autumn,and the maximum value (13.62 mg/g) appeared at the end of June. The seasonal averaged WUE_(GPP) was 5.97 mg/g, which was higher than that of forest ecosystem and lower than that of desert grassland ecosystem. GPP presented a quadratic relationship with vapor pressure deficit, air temperature and leaf area index, respectively, and a logarithmic relationship with canopy conductance. ET presented a quadratic relationship with air temperature,while its correlation with vapor pressure deficit,leaf area index and canopy conductance was non-significant. WUE_(GPP) presented a quadratic relationship with vapor pressure deficit, air temperature and leaf area index, respectively, and a logarithmic relationship with canopy conductance. Vapor pressure deficit equal to 2.0 kPa, leaf area index equal to 4.2 and canopy conductance equal to 0.002 m/s were the critical points that limit the increase of WUE_(GPP). When vapor pressure deficit was less than 2.0 kPa, WUE_(GPP) enlarged with the increase of vapor pressure deficit, and when it exceeded 2.0 kPa, the situation was opposite. With the increase of leaf area index, WUE_(GPP) enlarged gradually under low leaf area index, but when it exceeded 4.2, WUE_(GPP) did not increase and tended towards stability with the continual increase of leaf area index. With the increase of canopy conductance, WUE_(GPP) enlarged rapidly at begin, but slowly with the continual increase of canopy conductance when it exceeded the critical point. Water use efficiency expressed by other productive indexes was also estimated, including WUE_(NEP) (defined as the ratio of net ecosystem production, NEP, to ET) and WUE_(NPP) (defined as the ratio of net primary production, NPP, to ET). The seasonal variation of WUE_(NEP) and WUE_(NPP) presented a similar trend with WUE_(GPP). and their averages were 3.47 and 5.47 mg/g respectively. Comparison of WUE in different ecosystems found that leaf area index was the dominant factor of WUE magnitude because that leaf area index was a comprehensive reflection of air temperature and precipitation, while air temperature or precipitation alone can not determine the WUE of an ecosystem.
中文关键词	水分利用效率 ; 总初级生产力 ; 蒸散发 ; 影响因子
英文关键词	water use efficiency (WUE) gross primary productivity (GPP) evapotranspiration(ET) influential factor
语种	中文
国家	中国
收录类别	CSCD
WOS类目	BIOLOGY
WOS研究方向	Life Sciences & Biomedicine - Other Topics
CSCD记录号	CSCD:5346252
来源机构	中国科学院沈阳应用生态研究所
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/233140
作者单位	中国科学院沈阳应用生态研究所, 森林与土壤生态国家重点实验室, 沈阳, 辽宁 110016, 中国
推荐引用方式 GB/T 7714	李辉东,关德新,袁凤辉,等. 科尔沁草甸生态系统水分利用效率及影响因素[J]. 中国科学院沈阳应用生态研究所,2015,35(2):478-488.
APA	李辉东.,关德新.,袁凤辉.,王安志.,金昌杰.,...&井艳丽.(2015).科尔沁草甸生态系统水分利用效率及影响因素.生态学报,35(2),478-488.
MLA	李辉东,et al."科尔沁草甸生态系统水分利用效率及影响因素".生态学报 35.2(2015):478-488.