青藏高原是中国陆地生态系统的一个重要的碳汇功能区,但其碳汇强度及潜力的估算存在很大的差异,不利于区域碳中和目标的实现。基于涡度相关技术观测的原生高寒草地生态系统CO_(2)通量的40个站点年数据,结合2000年~2018年的年均气温、年...青藏高原是中国陆地生态系统的一个重要的碳汇功能区,但其碳汇强度及潜力的估算存在很大的差异,不利于区域碳中和目标的实现。基于涡度相关技术观测的原生高寒草地生态系统CO_(2)通量的40个站点年数据,结合2000年~2018年的年均气温、年均降水和年最大归一化植被指数(NDVIm)等因子,构建增强回归树模型以研究青海省陆地生态系统碳汇潜力及空间特征。结果表明增强回归树模型能够较好地模拟原生高寒草地碳汇强度的时空变异(R2=0.61),碳汇强度的观测值与模拟值的均方根误差和平均绝对误差分别为33.78 g C/m^(2)和26.63 g C/m^(2)。年均气温和NDVIm是高寒草地碳汇强度时空变异的主要影响因子,二者的相对贡献分别为48.6%和39.0%。青海省陆地生态系统每年的碳汇潜力平均为44.82±22.57 g C/m^(2)(平均值±标准差),高值区集中在海北州的中部及黄南州、果洛州和玉树州的东南部,低值区分布在海西州、海南州和海东市。青海省陆地生态系统每年的碳汇潜力总和为16.60 Mt C,其中高寒草甸和高寒草原分别为11.48 Mt C和3.13 Mt C,是青海省碳汇功能维持和提升的重点保育对象。研究结果可为青海省陆地生态系统的功能评估及率先实现碳中和目标提供数据支撑。展开更多
The meadow ecosystem on the Qing- hai-Tibetan Plateau is considered to be sensitive to climate change. An understanding of the alpine meadow ecosystem is therefore important for pre- dicting the response of ecosystems...The meadow ecosystem on the Qing- hai-Tibetan Plateau is considered to be sensitive to climate change. An understanding of the alpine meadow ecosystem is therefore important for pre- dicting the response of ecosystems to climate change. In this study, we use the coefficients of variation (Cv) and stability (E) obtained from the Haibei Alpine Meadow Ecosystem Research Station to characterize the ecosystem stability. The results suggest that the net primary production of the alpine meadow eco- system was more stable (Cv = 13.18%) than annual precipitation (Cv = 16.55%) and annual mean air temperature (Cv = 28.82%). The net primary produc- tion was insensitive to either the precipitation (E = 0.0782) or air temperature (E = 0.1113). In summary, the alpine meadow ecosystem on the Qinghai- Tibetan Plateau is much stable. Comparison of alpine meadow ecosystem stability with other five natural grassland ecosystems in Israel and southern African indicates that the alpine meadow ecosystem on the Qinghai-Tibetan Plateau is the most stable ecosys- tem. The alpine meadow ecosystem with relatively simple structure has high stability, which indicates that community stability is not only correlated with biodiversity and community complicity but also with environmental stability. An average oscillation cycles of 3―4 years existed in annual precipitation, annual mean air temperature, net primary production and the population size of consumers at the Haibei natural ecosystem. The high stability of the alpine meadow ecosystem may be resulting also from the adaptation of the ecosystem to the alpine environment.展开更多
Carbon dioxide fluxes of Kobresia humilis and Potentilla fruticosa shrub meadows,two typical ecosystems in the Qinghai-Tibet Plateau,were measured by eddy covari-ance technology and the data collected in August 2003 w...Carbon dioxide fluxes of Kobresia humilis and Potentilla fruticosa shrub meadows,two typical ecosystems in the Qinghai-Tibet Plateau,were measured by eddy covari-ance technology and the data collected in August 2003 were employed to analyze the relations between carbon dioxide fluxes and environmental factors of the ecosystems.August is the time when the two ecosystems reach their peak leaf area indexes and stay stable,and also the period when the net carbon absorptions of Kobresia humilis and Potentilla fruticosa shrub meadows reach 56.2 g C·m^(-2)and 32.6 g C·m^(-2),with their highest daily carbon dioxide absorp-tions standing at 12.7μmol·m^(-2)·s^(-1)and 9.3μmol·m^(-2)·s^(-1),and their highest carbon discharges at 5.1μmol·m^(-2)·s^(-1)and 5.7μmol·m^(-2)·s^(-1),respectively.At the same photosynthetic photo flux densities(PPFD),the carbon dioxide-uptake rate of the Kobresia humilis meadow is higher than that of the Potentilla fruticosa shrub meadow;where the PPFD are higher than 1,200μmol·m^(-2)·s^(-1).The carbon dioxide uptake rates of the two ecosystems declined as air temperature increased,but the carbon dioxide uptake rate of the Kobresia humilis meadow decreased more quickly(-0.086)than that of the Potentilla fruticosa shrub meadow(-0.016).Soil moistures exert influence on the soil respirations and this varies with the vegetation type.The daily carbon dioxide absorptions of the ecosystems increase with increased diurnal temperature differences and higher diurnal temperature differences result in higher carbon dioxide exchanges.There exists a negative correlation between the vegetation albedos and the carbon dioxide fluxes.展开更多
文摘青藏高原是中国陆地生态系统的一个重要的碳汇功能区,但其碳汇强度及潜力的估算存在很大的差异,不利于区域碳中和目标的实现。基于涡度相关技术观测的原生高寒草地生态系统CO_(2)通量的40个站点年数据,结合2000年~2018年的年均气温、年均降水和年最大归一化植被指数(NDVIm)等因子,构建增强回归树模型以研究青海省陆地生态系统碳汇潜力及空间特征。结果表明增强回归树模型能够较好地模拟原生高寒草地碳汇强度的时空变异(R2=0.61),碳汇强度的观测值与模拟值的均方根误差和平均绝对误差分别为33.78 g C/m^(2)和26.63 g C/m^(2)。年均气温和NDVIm是高寒草地碳汇强度时空变异的主要影响因子,二者的相对贡献分别为48.6%和39.0%。青海省陆地生态系统每年的碳汇潜力平均为44.82±22.57 g C/m^(2)(平均值±标准差),高值区集中在海北州的中部及黄南州、果洛州和玉树州的东南部,低值区分布在海西州、海南州和海东市。青海省陆地生态系统每年的碳汇潜力总和为16.60 Mt C,其中高寒草甸和高寒草原分别为11.48 Mt C和3.13 Mt C,是青海省碳汇功能维持和提升的重点保育对象。研究结果可为青海省陆地生态系统的功能评估及率先实现碳中和目标提供数据支撑。
文摘The meadow ecosystem on the Qing- hai-Tibetan Plateau is considered to be sensitive to climate change. An understanding of the alpine meadow ecosystem is therefore important for pre- dicting the response of ecosystems to climate change. In this study, we use the coefficients of variation (Cv) and stability (E) obtained from the Haibei Alpine Meadow Ecosystem Research Station to characterize the ecosystem stability. The results suggest that the net primary production of the alpine meadow eco- system was more stable (Cv = 13.18%) than annual precipitation (Cv = 16.55%) and annual mean air temperature (Cv = 28.82%). The net primary produc- tion was insensitive to either the precipitation (E = 0.0782) or air temperature (E = 0.1113). In summary, the alpine meadow ecosystem on the Qinghai- Tibetan Plateau is much stable. Comparison of alpine meadow ecosystem stability with other five natural grassland ecosystems in Israel and southern African indicates that the alpine meadow ecosystem on the Qinghai-Tibetan Plateau is the most stable ecosys- tem. The alpine meadow ecosystem with relatively simple structure has high stability, which indicates that community stability is not only correlated with biodiversity and community complicity but also with environmental stability. An average oscillation cycles of 3―4 years existed in annual precipitation, annual mean air temperature, net primary production and the population size of consumers at the Haibei natural ecosystem. The high stability of the alpine meadow ecosystem may be resulting also from the adaptation of the ecosystem to the alpine environment.
文摘Carbon dioxide fluxes of Kobresia humilis and Potentilla fruticosa shrub meadows,two typical ecosystems in the Qinghai-Tibet Plateau,were measured by eddy covari-ance technology and the data collected in August 2003 were employed to analyze the relations between carbon dioxide fluxes and environmental factors of the ecosystems.August is the time when the two ecosystems reach their peak leaf area indexes and stay stable,and also the period when the net carbon absorptions of Kobresia humilis and Potentilla fruticosa shrub meadows reach 56.2 g C·m^(-2)and 32.6 g C·m^(-2),with their highest daily carbon dioxide absorp-tions standing at 12.7μmol·m^(-2)·s^(-1)and 9.3μmol·m^(-2)·s^(-1),and their highest carbon discharges at 5.1μmol·m^(-2)·s^(-1)and 5.7μmol·m^(-2)·s^(-1),respectively.At the same photosynthetic photo flux densities(PPFD),the carbon dioxide-uptake rate of the Kobresia humilis meadow is higher than that of the Potentilla fruticosa shrub meadow;where the PPFD are higher than 1,200μmol·m^(-2)·s^(-1).The carbon dioxide uptake rates of the two ecosystems declined as air temperature increased,but the carbon dioxide uptake rate of the Kobresia humilis meadow decreased more quickly(-0.086)than that of the Potentilla fruticosa shrub meadow(-0.016).Soil moistures exert influence on the soil respirations and this varies with the vegetation type.The daily carbon dioxide absorptions of the ecosystems increase with increased diurnal temperature differences and higher diurnal temperature differences result in higher carbon dioxide exchanges.There exists a negative correlation between the vegetation albedos and the carbon dioxide fluxes.
