Carbon-water coupling and its relationship with environmental and biological factors in a planted Caragana liouana shrub community in desert steppe,northwest China  

宁夏荒漠草原区中间锦鸡儿灌丛群落碳水循环特征及其与生物环境因子的关系

作　　者：Ling-Tong Du Long-Long Ma Hai-Zhu Pan Cheng-Long Qiao Chen Meng Hong-Yue Wu Jing Tian Hong-Yi Yuan 

机构地区：[1]Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China,Ningxia University,Yinchuan 750021,China [2]Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China of Ministry of Education,Ningxia University,Yinchuan 750021,China [3]School of Ecology Environment,Ningxia University,Yinchuan 750021,China

出　　处：《Journal of Plant Ecology》2022年第5期947-960,共14页植物生态学报（英文版）

基　　金：the National Natural Science Foundation of China(41967027);the Natural Science Foundation of Ningxia Province(2022AAC02011);the Excellent Talents Support Program of Ningxia Province(RQoo12);the Key Research and Development Program of Ningxia Province(2021BEG02010);the Special Plan for Local Sci-Tech Development Guided by the Central Government of China.

摘　　要：The carbon and water cycle,an important biophysical process of terrestrial ecosystems,is changed by anthropogenic revegetation in arid and semiarid areas.However,there is still a lack of understanding of the mechanisms of carbon and water coupling in intrinsic ecosystems in the context of human activities.Based on the CO,and H,O flux measurements of the desert steppe with the planted shrub Caragana liouana,this study explored the carbon and water flux coupling of the ecosystem by analyzing the variations in gross primary productivity(GPP),evapotranspiration(ET)and water use efficiency(WUE)and discussing the driving mechanisms of biological factors.The seasonal variation in climate factors induced a periodic variation pattern of biophysical traits and carbon and water fluxes.The GPP and ET fluctuated in seasons,but the WUE was relatively stable in the growing season.The GP,ET and WUE were significantly driven by global radiation(R,),temperature(T,and T),water vapor pressure deficit,leaf area index and plant water stress index(PWSI).However,R,temperature and PWSI were the most important factors regulating WUE.R,and temperature directly affected WUE with a positive effect but indirectly inhibited WUE by rising PWSl.Plant water stress inhibited photosynthesis and transpiration of the planted shrub community in the desert steppe.When the plant water stress exceeded a threshold(PWSI>0.54),the WUE would decrease since the GPP responded more quickly to the plant water stress than ET.Our findings suggest that policies related to large-scale carbon sequestration initiatives under afforestation must first fully consider the status of water consumption and WUE.干旱半旱区的人工植被重建可能会改变陆地生态系统的重要生物物理过程星--碳水循环,然而在人类活动背景下,仍然缺乏对这些区域生态系统的碳水耦合机制的认识。本研究基于涡度相关系统测量了宁夏盐池荒漠草原区人工种植的中间锦鸡儿(Caragana liouana)灌丛群落的CO_(2)和H_(2)O通量,通过分析总初级生产力(gross primary productivity,GPP)、蒸散发(evapotranspiration,ET)和水分利用效率(water use efficiency,WUE)的变化,探讨了人工灌从生态系统碳水通量及其耦合关系,并进一步分析驱动其变化的生物环境因子。研究结果表明,气候因子的季节变化导致了生物物理特征和碳水通量呈周期性变化。在生长季,GPP和ET波动较大,而WUE变化相对稳定。GPP、ET和WUE显著受辐射(global radiation,R_(g))、温度(T_(a)和T_(s))、水汽压亏缺、叶面积指数和植物水分胁迫指数(plant water stress index,PWSI)的驱动。其中R_(g)、温度和PWSI是影响WUE的最重要因素。R_(g)和温度会对WUE产生直接的促进作用,但同时也会间接地提高PWSI进而抑制WUE。PWSI会抑制光合作用和蒸腾作用,当植物水分胁迫超过一个阈值(PWSI>0.54)时,WUE会下降,这是因为GPP对植物水分胁迫的响应比ET更敏感。这些研究结果表明,在荒漠草原区通过大规模种植灌木可实现固碳的作用,但也必须充分考虑区域的水资源消耗和水分利用效率的状况。

关 键 词：eddy covariance evapotranspiration(ET) gross primary production(GPP) water use eficiency(WUE) desert steppe Caragana liouana 

分 类 号：Q94[生物学—植物学]