The Qinling Mountains is not only the geographical boundary between North and South China,but also the boundary between subtropical and warm temperate zones.It plays an important role in the geo-ecological pattern of ...The Qinling Mountains is not only the geographical boundary between North and South China,but also the boundary between subtropical and warm temperate zones.It plays an important role in the geo-ecological pattern of China.However,there is controversy about the specific location of this geographical boundary in academic community due to the complexity,transition and heterogeneity of the transitional zone,as well as the differences in the delimitation indicators and research purposes.To further reveal the characteristics of the North-South transitional zone and clarify the specific location of the geo-ecological boundary between North and South China,combined with SRTM topographic data,temperature and precipitation data,Pinus massoniana forest and Pinus tabulaeformis forest,which represent subtropical coniferous forest in South China and temperate coniferous forest in North China respectively,were chosen to analyze their spatial distributions in the Qinling-Daba Mountains and the climatic conditions at their boundary with the climatic indexes of annual precipitation,the coldest month(January) average temperature,the warmest month(July) average temperature and the annual average temperature.The results show that:(1) Pinus massoniana and Pinus tabulaeformis forests and the climate indicators of their boundary can be used as one of the vegetation-climate indexes for the delimitation of subtropical and warm temperate zones.The boundary between the subtropical coniferous forest(Pinus massoniana forest) and temperate coniferous forest(Pinus tabulaeformis forest) is located along the south slope of Funiu Mountain to the north edge of Hanzhong Basin(the south slope of Qinling Mountains) at an altitude of 1000–1200 m,where the climatic indictors are stable:the annual precipitation is about 750–1000 mm,the annual average temperature is about 12–14℃,the coldest monthly average temperature is 0–4℃,and the warmest monthly average temperature is about 22–26℃.(2) It can be more scientifically to delimitate the boundary of subtropical and warm temperate zones in China by comprehensively considering the vegetation-climate indicators.Additionally,the boundary between subtropical and warm temperate zones in Qinling-Daba Mountains should be a transitional zone consisting of the boundaries of coniferous forests,broad-leaved forests and shrubs between subtropical and warm temperate zones.The results provide a scientific basis for the selection of delimitation index of subtropical and warm temperate zones.展开更多
在2017年1月1日-2017年12月31日期间,采用涡度相关法对位于亚热带⁃暖温带气候过渡区的河南宝天曼国家级自然保护区的65年生锐齿栎(Quercus aliena)天然次生林的碳通量进行了连续观测。结果表明:在观测期间,该森林生态系统在生长季5-10...在2017年1月1日-2017年12月31日期间,采用涡度相关法对位于亚热带⁃暖温带气候过渡区的河南宝天曼国家级自然保护区的65年生锐齿栎(Quercus aliena)天然次生林的碳通量进行了连续观测。结果表明:在观测期间,该森林生态系统在生长季5-10月份为碳汇,非生长季各月为碳源,净碳吸收量与释放量分别在7月和4月达到最大。净生态系统生产力为569.4 g C m-2a-1,生态系统呼吸为529.9 g C m-2a-1,总生态系统生产力为1099.3 g C m-2a-1。30min尺度上夜间净生态系统碳交换量与5cm深度土壤温度的关系可用指数方程表示(R2=0.21,P<0.001),其温度敏感性系数(Temperature sensitivity coefficient,Q10)为2.2。如果排除夜间通量观测的误差,处在海拔较高地区的夜间低温和非生长季的低温抑制了生态系统呼吸排放,可能导致全年生态系统呼吸量较低。在生长季5-10月份,各月的白天净生态系统碳交换量对光合有效辐射的响应符合直角双曲线模型,初始光能利用效率、平均最大光合速率和白天平均生态系统呼吸强度呈明显的季节变化,范围分别是0.06-0.12μmol CO2μmol-1 photon、0.44-1.47mg CO2m-2s-1和0.07-0.19 mg CO2m-2s-1。夏季7、8月份,较高的饱和水汽压差对白天锐齿栎林的碳吸收有明显的抑制作用;生长季末期9月份较高的土壤含水量对白天锐齿栎林的碳吸收也产生了抑制作用,表明生长末期降水过多影响森林的碳吸收。展开更多
Aims Fire and atmospheric nitrogen(N)deposition have the potential to influence growth and productivity of forest canopy.However,their impacts on photosynthesis and growth traits of understory plants in forests remain...Aims Fire and atmospheric nitrogen(N)deposition have the potential to influence growth and productivity of forest canopy.However,their impacts on photosynthesis and growth traits of understory plants in forests remain largely unexplored.This study was conducted to examine the effects of burning and N addition on foliar N content,net photosynthesis and growth traits of three dominant shrub species(Vitex negundo,Lindera glauca and Symplocos chinensis)in a temperate forest in Central China.Methods The experiment used a pair-nested design,with four treatments(control,burning,N addition and burning plus N addition)and five replicates.Leaf mass area(LMA),area-based concentrations of foliar N and chlorophyll(N_(area) and Chl_(area)),net photosynthesis(A_(n)),stomatal conductance(g_(s)),maximum photosynthetic rate(A_(max))and maximal carboxylation rate(V_(cmax)),basal diameter,height and branch length(BL)of the three species were measured.Important Findings Across the three species,burning stimulated LMA,N_(area),Chl_(area),A_(n),g_(s),A_(max) and V_(cmax),and consequently enhanced basal diam-eter,height and BL.Nitrogen addition increased A_(n) and gs but did not affect LMA,N_(area),Chl_(area),A_(max),V_(cmax),basal diameter,height or BL.However,N addition strengthened the positive effects of burning on g_(s),V_(cmax),A_(n) and BL.The findings indicate the primary role of light resources in determining plant photosynthesis and growth of understory shrub species after fire and highlight that understory plants should be considered in projection of biomass accumulation and productivity of forests under environmental perturbations.展开更多
基金National Natural Science Foundation of China,No.41871350Scientific and Technological Basic Resources Survey Project,No.2017FY100900。
文摘The Qinling Mountains is not only the geographical boundary between North and South China,but also the boundary between subtropical and warm temperate zones.It plays an important role in the geo-ecological pattern of China.However,there is controversy about the specific location of this geographical boundary in academic community due to the complexity,transition and heterogeneity of the transitional zone,as well as the differences in the delimitation indicators and research purposes.To further reveal the characteristics of the North-South transitional zone and clarify the specific location of the geo-ecological boundary between North and South China,combined with SRTM topographic data,temperature and precipitation data,Pinus massoniana forest and Pinus tabulaeformis forest,which represent subtropical coniferous forest in South China and temperate coniferous forest in North China respectively,were chosen to analyze their spatial distributions in the Qinling-Daba Mountains and the climatic conditions at their boundary with the climatic indexes of annual precipitation,the coldest month(January) average temperature,the warmest month(July) average temperature and the annual average temperature.The results show that:(1) Pinus massoniana and Pinus tabulaeformis forests and the climate indicators of their boundary can be used as one of the vegetation-climate indexes for the delimitation of subtropical and warm temperate zones.The boundary between the subtropical coniferous forest(Pinus massoniana forest) and temperate coniferous forest(Pinus tabulaeformis forest) is located along the south slope of Funiu Mountain to the north edge of Hanzhong Basin(the south slope of Qinling Mountains) at an altitude of 1000–1200 m,where the climatic indictors are stable:the annual precipitation is about 750–1000 mm,the annual average temperature is about 12–14℃,the coldest monthly average temperature is 0–4℃,and the warmest monthly average temperature is about 22–26℃.(2) It can be more scientifically to delimitate the boundary of subtropical and warm temperate zones in China by comprehensively considering the vegetation-climate indicators.Additionally,the boundary between subtropical and warm temperate zones in Qinling-Daba Mountains should be a transitional zone consisting of the boundaries of coniferous forests,broad-leaved forests and shrubs between subtropical and warm temperate zones.The results provide a scientific basis for the selection of delimitation index of subtropical and warm temperate zones.
文摘河岸林过渡带是河岸带的重要组成部分,在保护河岸带生态系统的结构、功能及其生物多样性方面有着重要的作用.河岸林林分过渡带宽度的划分是研究和保护河岸林及其群落的基础,也是河岸带生态系统管理和保护的必要工作.为了探究河岸林林分过渡带宽度划分的方法,采用重要值法对吕梁山西部山区山西省临沧市隰县下李林场的河岸林宽度进行判定.研究结果表明:不同林型的河岸林的过渡带宽度不同;河岸落叶松林过渡带宽度为40 m,河岸油松林过渡带宽度为20 m.
文摘在2017年1月1日-2017年12月31日期间,采用涡度相关法对位于亚热带⁃暖温带气候过渡区的河南宝天曼国家级自然保护区的65年生锐齿栎(Quercus aliena)天然次生林的碳通量进行了连续观测。结果表明:在观测期间,该森林生态系统在生长季5-10月份为碳汇,非生长季各月为碳源,净碳吸收量与释放量分别在7月和4月达到最大。净生态系统生产力为569.4 g C m-2a-1,生态系统呼吸为529.9 g C m-2a-1,总生态系统生产力为1099.3 g C m-2a-1。30min尺度上夜间净生态系统碳交换量与5cm深度土壤温度的关系可用指数方程表示(R2=0.21,P<0.001),其温度敏感性系数(Temperature sensitivity coefficient,Q10)为2.2。如果排除夜间通量观测的误差,处在海拔较高地区的夜间低温和非生长季的低温抑制了生态系统呼吸排放,可能导致全年生态系统呼吸量较低。在生长季5-10月份,各月的白天净生态系统碳交换量对光合有效辐射的响应符合直角双曲线模型,初始光能利用效率、平均最大光合速率和白天平均生态系统呼吸强度呈明显的季节变化,范围分别是0.06-0.12μmol CO2μmol-1 photon、0.44-1.47mg CO2m-2s-1和0.07-0.19 mg CO2m-2s-1。夏季7、8月份,较高的饱和水汽压差对白天锐齿栎林的碳吸收有明显的抑制作用;生长季末期9月份较高的土壤含水量对白天锐齿栎林的碳吸收也产生了抑制作用,表明生长末期降水过多影响森林的碳吸收。
基金This work was financially supported by the National Natural Science Foundation of China(31430015).
文摘Aims Fire and atmospheric nitrogen(N)deposition have the potential to influence growth and productivity of forest canopy.However,their impacts on photosynthesis and growth traits of understory plants in forests remain largely unexplored.This study was conducted to examine the effects of burning and N addition on foliar N content,net photosynthesis and growth traits of three dominant shrub species(Vitex negundo,Lindera glauca and Symplocos chinensis)in a temperate forest in Central China.Methods The experiment used a pair-nested design,with four treatments(control,burning,N addition and burning plus N addition)and five replicates.Leaf mass area(LMA),area-based concentrations of foliar N and chlorophyll(N_(area) and Chl_(area)),net photosynthesis(A_(n)),stomatal conductance(g_(s)),maximum photosynthetic rate(A_(max))and maximal carboxylation rate(V_(cmax)),basal diameter,height and branch length(BL)of the three species were measured.Important Findings Across the three species,burning stimulated LMA,N_(area),Chl_(area),A_(n),g_(s),A_(max) and V_(cmax),and consequently enhanced basal diam-eter,height and BL.Nitrogen addition increased A_(n) and gs but did not affect LMA,N_(area),Chl_(area),A_(max),V_(cmax),basal diameter,height or BL.However,N addition strengthened the positive effects of burning on g_(s),V_(cmax),A_(n) and BL.The findings indicate the primary role of light resources in determining plant photosynthesis and growth of understory shrub species after fire and highlight that understory plants should be considered in projection of biomass accumulation and productivity of forests under environmental perturbations.
