Climate change is now evident in the Qinghai-Tibet Plateau(QTP), with impacts on the alpine ecosystem, particularly on water and heat balance between the active layer and the atmosphere. Thus, we document the basic ch...Climate change is now evident in the Qinghai-Tibet Plateau(QTP), with impacts on the alpine ecosystem, particularly on water and heat balance between the active layer and the atmosphere. Thus, we document the basic characteristics of changes in the water and heat dynamics in response to experimental warming in a typical alpine swamp meadow ecosystem. Data sets under open top chambers(OTC) and the control manipulations were collected over a complete year. The results show that annual(2008) air temperatures of OTC-1 and OTC-2 were 6.7 °C and 3.5 °C warmer than the control. Rising temperature promotes plant growth and development. The freeze-thaw and isothermal days of OTCs appeared more frequently than the control, owing to comparably higher water and better vegetation conditions. OTCs soil moisture decreased with the decrease of soil depth; however, there was an obviously middle dry aquifer of the control, which is familiar in QTP. Moreover, experimental warming led to an increase in topsoil water content due to poorly drained swamp meadow ecosystem with higher organic matter content and thicker root horizons. The results of this study will have some contributions to alpine cold ecosystem water-heat process and water cycle under climate change.展开更多
Aims The mature meadows(MMs)and the swamp meadows(SMs)are the two most important ecosystems in the eastern Tibetan Plateau,China.Besides their substantial differences in terms of soil water conditions and thereby the ...Aims The mature meadows(MMs)and the swamp meadows(SMs)are the two most important ecosystems in the eastern Tibetan Plateau,China.Besides their substantial differences in terms of soil water conditions and thereby the soil oxygen and nutrients,however,little is known about the differences in community composition,struc-ture,traits and productivity between these two meadows.We par-ticularly ask whether light availability mediated by physical structure heterogeneity is a key determinant of the difference in community composition and productivity between these two meadows.Methods We examined the community structure,composition,aboveground net primary productivity(ANPP),light availability in understory and the community-weighted means(CWMs)for leaf morphological and physiological traits in 12 random plots(5 m×5 m)for each of the studied habitats.Important findings The results showed that plant community in the MM had higher variation in both vertical and horizontal structure and thus had more light availability in the understory.The MM had higher spe-cies richness and greater ANPP than the SM.The CWMs of leaf morphological and physiological traits for species in the MM fea-tured a fast-growing strategy(i.e.higher height,leaf area and net photosynthesis rate and lower nitrogen:phosphorus ratio),in con-trast to those in the SM.We also found that there were significant correlations between the CWM of traits and the ANPP,indicating that some key traits in these habitats have linked to community productivity.Our study also suggests that the heterogeneity in the community structure,which affects light availability in the under-story,may play an important role in determining the community composition and productivity.In conclusion,our study revealed significant differences in community structure,composition and traits between the MM and the SM,and the light availability that related closely to community structure is the key factor to deter-mine the composition and productivity of the community of these two habitats.展开更多
为深入了解高寒湿地生态系统氧化亚氮(N_(2)O)排放对气候变暖及氮沉降的响应,以青藏高原尕海湿地区沼泽草甸为研究对象,利用开顶箱(Open top chamber,OTC)增温和外源氮素添加来模拟未来气候变暖以及氮沉降,布设对照(CK),增温(W),施氮(N...为深入了解高寒湿地生态系统氧化亚氮(N_(2)O)排放对气候变暖及氮沉降的响应,以青藏高原尕海湿地区沼泽草甸为研究对象,利用开顶箱(Open top chamber,OTC)增温和外源氮素添加来模拟未来气候变暖以及氮沉降,布设对照(CK),增温(W),施氮(N)和增温+施氮(WN)_(4)种处理,采用静态箱—气相色谱法监测不同处理下植物生长季N_(2)O排放,并探究了N_(2)O排放与环境因子之间的关系。结果表明:仅W与WN处理的N_(2)O排放通量始终高于对照,日均排放通量高出对照组22.41%和56.90%;WN,N,W和CK处理下N_(2)O累计排放量分别为0.87,1.07,1.09和1.37 kg·hm^(-2)N;生长季末期土壤N_(2)O短暂的由“源”向“汇”转变;N_(2)O排放通量与地下生物量显著负相关(P<0.05),与含水量和硝酸酶活性显著正相关(P<0.05),与温度、硝态氮和铵态氮极显著正相关(P<0.01)。本研究可为未来高寒湿地生态系统在全球气候变化下温室气体排放的预测提供科学依据。展开更多
基金funded by The Natural Science foundation of China (No. 40925002)The Natural Science foundation of Fujian Province (No. 2015J05114)
文摘Climate change is now evident in the Qinghai-Tibet Plateau(QTP), with impacts on the alpine ecosystem, particularly on water and heat balance between the active layer and the atmosphere. Thus, we document the basic characteristics of changes in the water and heat dynamics in response to experimental warming in a typical alpine swamp meadow ecosystem. Data sets under open top chambers(OTC) and the control manipulations were collected over a complete year. The results show that annual(2008) air temperatures of OTC-1 and OTC-2 were 6.7 °C and 3.5 °C warmer than the control. Rising temperature promotes plant growth and development. The freeze-thaw and isothermal days of OTCs appeared more frequently than the control, owing to comparably higher water and better vegetation conditions. OTCs soil moisture decreased with the decrease of soil depth; however, there was an obviously middle dry aquifer of the control, which is familiar in QTP. Moreover, experimental warming led to an increase in topsoil water content due to poorly drained swamp meadow ecosystem with higher organic matter content and thicker root horizons. The results of this study will have some contributions to alpine cold ecosystem water-heat process and water cycle under climate change.
基金This work was supported by National Natural Science Foundation of China(grant No.41171214).
文摘Aims The mature meadows(MMs)and the swamp meadows(SMs)are the two most important ecosystems in the eastern Tibetan Plateau,China.Besides their substantial differences in terms of soil water conditions and thereby the soil oxygen and nutrients,however,little is known about the differences in community composition,struc-ture,traits and productivity between these two meadows.We par-ticularly ask whether light availability mediated by physical structure heterogeneity is a key determinant of the difference in community composition and productivity between these two meadows.Methods We examined the community structure,composition,aboveground net primary productivity(ANPP),light availability in understory and the community-weighted means(CWMs)for leaf morphological and physiological traits in 12 random plots(5 m×5 m)for each of the studied habitats.Important findings The results showed that plant community in the MM had higher variation in both vertical and horizontal structure and thus had more light availability in the understory.The MM had higher spe-cies richness and greater ANPP than the SM.The CWMs of leaf morphological and physiological traits for species in the MM fea-tured a fast-growing strategy(i.e.higher height,leaf area and net photosynthesis rate and lower nitrogen:phosphorus ratio),in con-trast to those in the SM.We also found that there were significant correlations between the CWM of traits and the ANPP,indicating that some key traits in these habitats have linked to community productivity.Our study also suggests that the heterogeneity in the community structure,which affects light availability in the under-story,may play an important role in determining the community composition and productivity.In conclusion,our study revealed significant differences in community structure,composition and traits between the MM and the SM,and the light availability that related closely to community structure is the key factor to deter-mine the composition and productivity of the community of these two habitats.
文摘为深入了解高寒湿地生态系统氧化亚氮(N_(2)O)排放对气候变暖及氮沉降的响应,以青藏高原尕海湿地区沼泽草甸为研究对象,利用开顶箱(Open top chamber,OTC)增温和外源氮素添加来模拟未来气候变暖以及氮沉降,布设对照(CK),增温(W),施氮(N)和增温+施氮(WN)_(4)种处理,采用静态箱—气相色谱法监测不同处理下植物生长季N_(2)O排放,并探究了N_(2)O排放与环境因子之间的关系。结果表明:仅W与WN处理的N_(2)O排放通量始终高于对照,日均排放通量高出对照组22.41%和56.90%;WN,N,W和CK处理下N_(2)O累计排放量分别为0.87,1.07,1.09和1.37 kg·hm^(-2)N;生长季末期土壤N_(2)O短暂的由“源”向“汇”转变;N_(2)O排放通量与地下生物量显著负相关(P<0.05),与含水量和硝酸酶活性显著正相关(P<0.05),与温度、硝态氮和铵态氮极显著正相关(P<0.01)。本研究可为未来高寒湿地生态系统在全球气候变化下温室气体排放的预测提供科学依据。
