From July 2008 to August 2008, 72 leaf samples from 22 species and 81 soil samples in the nine natural forest ecosystems were collected, from north to south along the North-South Transect of Eastern China （NSTEC）. B...From July 2008 to August 2008, 72 leaf samples from 22 species and 81 soil samples in the nine natural forest ecosystems were collected, from north to south along the North-South Transect of Eastern China （NSTEC）. Based on these samples, we studied the geographical distribution patterns of vegetable water use efficiency （WUE） and nitrogen use efficiency （NUE）, and analyzed their relationship with environmental factors. The vegetable WUE and NUE were calculated through the measurement of foliar δ 13C and C/N of predominant species, respectively. The results showed： （1） vegetable WUE, ranging from 2.13 to 28.67 mg C g-1 H2O, increased linearly from south to north in the representative forest ecosystems along the NSTEC, while vegetable NUE showed an opposite trend, increasing from north to south, ranging from 12.92 to 29.60 g C g-1 N. （2） Vegetable WUE and NUE were dominantly driven by climate and significantly affected by soil nutrient factors. Based on multiple stepwise regression analysis, mean annual temperature, soil phosphorus concentration, and soil nitrogen concentration were responding for 75.5% of the variations of WUE （p0.001）. While, mean annual precipitation and soil phosphorus concentration could explain 65.7% of the change in vegetable NUE （p0.001）. Moreover, vegetable WUE and NUE would also be seriously influenced by atmospheric nitrogen deposition in nitrogen saturated ecosystems. （3） There was a significant trade-off relationship between vegetable WUE and NUE in the typical forest ecosystems along the NSTEC （p0.001）, indicating a balanced strategy for vegetation in resource utilization in natural forest ecosystems along the NSTEC. This study suggests that global change would impact the resource use efficiency of forest ecosystems. However, vegetation could adapt to those changes by increasing the use efficiency of shortage resource while decreasing the relatively ample one. But extreme impacts, such as heavy nitrogen deposition, would break this trade-off mechanism and give a dramatic disturbance to the ecosystem biogeochemical cycle.展开更多
The ratio of transpiration to evapotranspiration (T/ET) is a key parameter for quantifying water use efficiency of ecosystems and understanding the interaction between ecosystem carbon uptake and water cycling in the ...The ratio of transpiration to evapotranspiration (T/ET) is a key parameter for quantifying water use efficiency of ecosystems and understanding the interaction between ecosystem carbon uptake and water cycling in the context of global change.The estimation of T/ET has been paid increasing attention from the scientific community in recent years globally.In this paper,we used the Priestly-Taylor Jet Propulsion Laboratory Model (PT-JPL) driven by regional remote sensing data and gridded meteorological data,to simulate the T/ET in forest ecosystems along the North-South Transect of East China (NSTEC) during 2001-2010,and to analyze the spatial distribution and temporal variation of T/ET,as well as the factors influencing the variation in T/ET.The results showed that:(1) The PT-JPL model is suitable for the simulation of evapotranspiration and its components of forest ecosystems in Eastern China,and has relatively good stability and reliability.(2) Spatial distribution of T/ET in forest ecosystems along NSTEC was heterogeneous,i.e.,T/ET was higher in the north and lower in the south,with an averaged value of 0.69;and the inter-annual variation of T/ET showed a significantly increasing trend,with an increment of 0.007/yr (p<0.01).(3) Seasonal and inter- annual variations of T/ET had different dominant factors.Temperature and EVI can explain around 90%(p<0.01) of the seasonal variation in T/ET,while the inter-annual variation in T/ET was mainly controlled by EVI (53%,p<0.05).展开更多
The Qinling-Daba Mountains are the main body of China’s North-South Transitional Zone.Analysis of the north-south gradual variation of vegetation components is significant for understanding the structural diversity a...The Qinling-Daba Mountains are the main body of China’s North-South Transitional Zone.Analysis of the north-south gradual variation of vegetation components is significant for understanding the structural diversity and complexity of this transitional zone.In this study,based on survey data of plant communities,the eastern Qinling-Daba Mountains is divided into four geographic units:the north flank of eastern Qinling Mts.,south flank of eastern Qinling Mts.,north flank of eastern Daba Mts.and south flank of eastern Daba Mts.We also explore division of regional climate according to areal differentiation of plant-species,community structure and species-richness,respectively.The results show that,(1)at plant-species level,there are mainly northern plants in north flank of eastern Qinling Mts.with evergreen species and fewer northern plants in south flank of eastern Qinling Mts.;there are mainly southern plants in eastern Daba Mts.(2)At community structure level,there are 4 formations(3 northern formations and 1 widespread formation)in north flank of eastern Qinling,6 formations(3 northern formations,1 southern formation,and 2 widespread formations)in south flank of eastern Qinling,4 formations(2 southern formations and 2 widespread formations)in north flank of eastern Daba Mts.,and 3 formations(3 southern formations)in south flank of eastern Daba Mts.In terms of the numbers and properties of formations,there is a mixture of northern and southern formations only in the south flank of eastern Qinling Mts.(3)At species-richness level,the diversity of families,genera and species decreased with increasing latitude,but the mixing of northern plants and the southern plants began to occur in south flank of eastern Qinling Mts.This means that the south flank of the eastern Qinling Mts.serves more suitably as the dividing line between China’s warm temperate and subtropical zones.展开更多
基金National Natural Science Foundation of China No.30590381 No.31000211 National Basic Research Program of China No.2010CB833504
文摘From July 2008 to August 2008, 72 leaf samples from 22 species and 81 soil samples in the nine natural forest ecosystems were collected, from north to south along the North-South Transect of Eastern China （NSTEC）. Based on these samples, we studied the geographical distribution patterns of vegetable water use efficiency （WUE） and nitrogen use efficiency （NUE）, and analyzed their relationship with environmental factors. The vegetable WUE and NUE were calculated through the measurement of foliar δ 13C and C/N of predominant species, respectively. The results showed： （1） vegetable WUE, ranging from 2.13 to 28.67 mg C g-1 H2O, increased linearly from south to north in the representative forest ecosystems along the NSTEC, while vegetable NUE showed an opposite trend, increasing from north to south, ranging from 12.92 to 29.60 g C g-1 N. （2） Vegetable WUE and NUE were dominantly driven by climate and significantly affected by soil nutrient factors. Based on multiple stepwise regression analysis, mean annual temperature, soil phosphorus concentration, and soil nitrogen concentration were responding for 75.5% of the variations of WUE （p0.001）. While, mean annual precipitation and soil phosphorus concentration could explain 65.7% of the change in vegetable NUE （p0.001）. Moreover, vegetable WUE and NUE would also be seriously influenced by atmospheric nitrogen deposition in nitrogen saturated ecosystems. （3） There was a significant trade-off relationship between vegetable WUE and NUE in the typical forest ecosystems along the NSTEC （p0.001）, indicating a balanced strategy for vegetation in resource utilization in natural forest ecosystems along the NSTEC. This study suggests that global change would impact the resource use efficiency of forest ecosystems. However, vegetation could adapt to those changes by increasing the use efficiency of shortage resource while decreasing the relatively ample one. But extreme impacts, such as heavy nitrogen deposition, would break this trade-off mechanism and give a dramatic disturbance to the ecosystem biogeochemical cycle.
基金National Key Research and Development Program of China,No.2015CB954102National Natural Science Foundation of China,No.31700417,No.41571424
文摘The ratio of transpiration to evapotranspiration (T/ET) is a key parameter for quantifying water use efficiency of ecosystems and understanding the interaction between ecosystem carbon uptake and water cycling in the context of global change.The estimation of T/ET has been paid increasing attention from the scientific community in recent years globally.In this paper,we used the Priestly-Taylor Jet Propulsion Laboratory Model (PT-JPL) driven by regional remote sensing data and gridded meteorological data,to simulate the T/ET in forest ecosystems along the North-South Transect of East China (NSTEC) during 2001-2010,and to analyze the spatial distribution and temporal variation of T/ET,as well as the factors influencing the variation in T/ET.The results showed that:(1) The PT-JPL model is suitable for the simulation of evapotranspiration and its components of forest ecosystems in Eastern China,and has relatively good stability and reliability.(2) Spatial distribution of T/ET in forest ecosystems along NSTEC was heterogeneous,i.e.,T/ET was higher in the north and lower in the south,with an averaged value of 0.69;and the inter-annual variation of T/ET showed a significantly increasing trend,with an increment of 0.007/yr (p<0.01).(3) Seasonal and inter- annual variations of T/ET had different dominant factors.Temperature and EVI can explain around 90%(p<0.01) of the seasonal variation in T/ET,while the inter-annual variation in T/ET was mainly controlled by EVI (53%,p<0.05).
基金National Scientific and Technological Basic Resources Investigation Project,No.2017FY100900。
文摘The Qinling-Daba Mountains are the main body of China’s North-South Transitional Zone.Analysis of the north-south gradual variation of vegetation components is significant for understanding the structural diversity and complexity of this transitional zone.In this study,based on survey data of plant communities,the eastern Qinling-Daba Mountains is divided into four geographic units:the north flank of eastern Qinling Mts.,south flank of eastern Qinling Mts.,north flank of eastern Daba Mts.and south flank of eastern Daba Mts.We also explore division of regional climate according to areal differentiation of plant-species,community structure and species-richness,respectively.The results show that,(1)at plant-species level,there are mainly northern plants in north flank of eastern Qinling Mts.with evergreen species and fewer northern plants in south flank of eastern Qinling Mts.;there are mainly southern plants in eastern Daba Mts.(2)At community structure level,there are 4 formations(3 northern formations and 1 widespread formation)in north flank of eastern Qinling,6 formations(3 northern formations,1 southern formation,and 2 widespread formations)in south flank of eastern Qinling,4 formations(2 southern formations and 2 widespread formations)in north flank of eastern Daba Mts.,and 3 formations(3 southern formations)in south flank of eastern Daba Mts.In terms of the numbers and properties of formations,there is a mixture of northern and southern formations only in the south flank of eastern Qinling Mts.(3)At species-richness level,the diversity of families,genera and species decreased with increasing latitude,but the mixing of northern plants and the southern plants began to occur in south flank of eastern Qinling Mts.This means that the south flank of the eastern Qinling Mts.serves more suitably as the dividing line between China’s warm temperate and subtropical zones.
