It is difficult to scale up measurements of the sap flux density(J_S) for the characterization of tree or stand transpiration(E) due to spatial variations in J_S and their temporal changes.To assess spatial variations...It is difficult to scale up measurements of the sap flux density(J_S) for the characterization of tree or stand transpiration(E) due to spatial variations in J_S and their temporal changes.To assess spatial variations in the sap flux density of Korean pine(Pinus koraiensis) and their effects on E estimates,we measured the J_S using Granier-type sensors.Within trees,the J_S decreased exponentially with the radial depth,and the J_S of the east aspects were higher than those of the west aspects.Among trees,there was a positive relationship between J_S and the tree diameter at breast height,and this positive relationship became stronger as the transpiration demand increased.The spatial variations that caused large errors in E estimates(i.e.,up to 110.8 % when radial variation was ignored) had varied systematically with environmental factors systematic characteristics in relation to environmental factors.However,changes in these variations did not generate substantial errors in the E estimates.For our study periods,the differences in the daily E(E_D) calculated by ignoring radial,azimuthal and tree-to-tree variations and the measured E_D were fairly constant,especially when the daily vapor pressure deficit(D_D)was higher than 0.6 k Pa.These results imply that the effect of spatial variations changes on sap flow can be a minor source of error compared with spatial variations(radial,azimuthal and tree-to-tree variations) when considering E estimates.展开更多
Based on the advantages of the wavelet to separate regional field and local anomalies in MATLAB environment,a high-precision regional-residual separation was finally realized. Analytical continuation and trend surface...Based on the advantages of the wavelet to separate regional field and local anomalies in MATLAB environment,a high-precision regional-residual separation was finally realized. Analytical continuation and trend surface analysis are conventional methods for gravity anomaly separation. But the wavelet packet analysis in analyzing gravity data can make the gravity anomaly to be computed at a higher precision. In this paper,wavelet packet method is used to process gravity anomaly data obtained in Laos,and the separation result is good. Daubechies wavelet series has a higher precision in the wavelet packet.展开更多
Research on the relationship between national resource constraint-region types and environmental carrying capacity is essential for the continued development of Chinese industrialization and urbanization.Thus,utilizin...Research on the relationship between national resource constraint-region types and environmental carrying capacity is essential for the continued development of Chinese industrialization and urbanization.Thus,utilizing a series of key indexes including the per-capita potential of available land resources,the per-capita potential of available water resources,the degree of environmental stress,and the degree of ecological restriction,a step-by-step,integrated measuring method is presented here to understand the constrained carrying elements of water and land resources as well as environment and ecology.Spatial differences are analyzed and area types classified at the county level across China.Results reveal that：（1）Almost 90%of China is strongly constrained by both resources and the environment,while nearly 50%of national territory is strongly constrained by two elements,especially in areas of intensive population and industry to the east of the Helan-Longmen Mountain line;（2）Densely populated areas of eastern and central China,as well as on the Tibetan Plateau,are strongly constrained by a shortage of land resources,while North China,the northwest,northeast,the Sichuan basin,and some southern cities are experiencing strong constraints because of water shortages.In contrast,the North China plain,the Yangtze River delta,northern Jiangsu,Sichuan province,Chongqing municipality,Guizhou and Guangxi provinces,the northeast plain,and the northern Loess Plateau are constrained by high levels of environmental stress.Areas of China that are strongly ecologically constrained tend to be concentrated to the southwest of the Tianshan-Dabie Mountain line,as well as in the northeast on the Loess Plateau,in the Alashan of Inner Mongolia,in northeast China,and in the northern Jiangsu coastal area;（3）Constraints on national resources and environmental carrying capacity are diverse and cross-cut China,meanwhile,multi-element spatial distribution does reveal a degree of relative centralization.With the exception of the Tibetan Plateau which is resources-ecological constraint,other areas subject to cross constraints are mainly concentrated to the east of the Helan-Longmen Mountain line.展开更多
By analyzing and comparing the existing methods for the division of urban economic region, this paper supplemented and developed the breaking point theory. In this model, put forward for the first time using ＂the spa...By analyzing and comparing the existing methods for the division of urban economic region, this paper supplemented and developed the breaking point theory. In this model, put forward for the first time using ＂the space-time distance＂ to replace ＂the space- linear distance＂ and ＂the city comprehensiveness quality- fuzzy comprehensive assessment Index＂ to ＂the urban population or GDP＇. Set up the algorithm of including ＂the space- time distance＂ and the city radiation scope changed with the changes of traffic conditions. Thus has realized ＂dynamically＂ tracing of the city radiation scope influenced by the traffic conditions. Taking Yichang city as an example, the paper analyzed the city function localization in the times of new traffic environments. Because China＇s cities are at the times of the traffic great changes, therefore, the method and the main conclusions of this paper have some methodology guiding sense to the majority cities of deffernt country to re-position.展开更多
Glycerol dialkyl glycerol tetraethers(GDGTs) in lake sediments are useful biomarkers for the continental paleoclimatic reconstruction. However, the environmental controls on the distribution of these compounds, in par...Glycerol dialkyl glycerol tetraethers(GDGTs) in lake sediments are useful biomarkers for the continental paleoclimatic reconstruction. However, the environmental controls on the distribution of these compounds, in particular the 6-methyl isomers of bacterial branched GDGTs(bGDGTs), in the lakes with contrasting pH, are still unknown, hindering their application for paleo-reconstructions. Here, we investigated the environmental impacts on the distribution of GDGTs in 17 alkaline lakes and 1 acid lake in China. It was found that the dissolved oxygen content in water column may have an impact on the distribution of archaeal isoprenoid GDGTs(iGDGTs) by causing the change in archaeal communities. The ratio of GDGT-0/crenarchaeol increases with decreasing oxygen content, indicating that the relative abundance of anaerobic methanogenic archaea or Miscellaneous Crenarchaeotic Group(MCG) vs. aerobic Thaumarchaeota is controlled by the oxygen content dissolved in water of these lakes. Thaumarchaeota are likely to contribute only a small proportion of iGDGTs in the relatively oxygen-depleted lakes, and thus TEX_(86) is not suitable for the reconstruction of the surface temperature of these lakes. The abundance ratio of iGDGTs to bGDGTs(R_(i/b)) appears to show no relationship with water pH in all the lakes, but exhibits a significant positive correlation with the water depth of the acid Lake Qinghai in Tengchong. As expected, the methylation degree of bGDGTs(MBT′) was found to correlate with both mean annual air temperature(MAT) and water pH, and the cyclization degree of bGDGTs(CBT) correlates only with water pH in these lakes. However, the MBT′_(5ME), an index to measure the methylation degree of 5-methyl bGDGTs, exhibits no relationship with MAT, whereas MBT′_(6ME), the methylation degree of 6-methyl bGDGTs, was found to correlate significantly with MAT. This is opposite to the situation observed in the global soils, pointing to a different adaptation of b GDGT-producing bacteria to environmental variables or different microbial sources of bGDGTs in these lakes. The relative abundance of 6- vs. 5-methyl bGDGTs is controlled by pH in these lakes, similar to that observed in worldwide soils. Hence, the isomer ratio(IR) of 6-methyl bGDGTs or CBT′ can be used as a proxy for water pH, although they might be influenced by other environmental factors including temperature in the lakes with a narrow range of pH.展开更多
Individual behavioral variation is ubiquitous across taxa and important to understand if we wish to fully use beha- vioral data to understand the ecology and evolution of organisms. Only recently have studies of indiv...Individual behavioral variation is ubiquitous across taxa and important to understand if we wish to fully use beha- vioral data to understand the ecology and evolution of organisms. Only recently have studies of individual variation in dispersal behavior become a focus of research. A better understanding of individual variation in dispersal behavior is likely to improve our understanding of population dynamics. In particular, the dynamics of critically small populations （endangered species） and large populations （pest species） may be driven by unique dispersal variants. Here we documented individual variation in the ballooning dispersal behavior of Western black widow spiderlings Latrodectus hesperus, an urban pest species found in superabundant in- festations throughout cities of the desert Southwest USA. We found a great deal of family-level variation in ballooning dispersal, and this variation was highly consistent （repeatable） across time. Maternal egg investment was a poor predictor of this ballooning dispersal. Instead, we show that spiderlings reared in isolation are significantly slower to disperse than spiderlings raised in a more natural setting surrounded by full siblings. Thus, our study examines a widespread but poorly understood dispersal behavior （ballooning）, and suggests urban pest population dynamics are likely driven by the interaction of variation in individuals, families and social environments展开更多
基金supported by both the Korea Forest Service(S211315L020120,S111215L020110)the Korea Meteorology Agency(KMIPA-20120001-2)the support of the Mt.Teahwa Seoul National University Forest
文摘It is difficult to scale up measurements of the sap flux density(J_S) for the characterization of tree or stand transpiration(E) due to spatial variations in J_S and their temporal changes.To assess spatial variations in the sap flux density of Korean pine(Pinus koraiensis) and their effects on E estimates,we measured the J_S using Granier-type sensors.Within trees,the J_S decreased exponentially with the radial depth,and the J_S of the east aspects were higher than those of the west aspects.Among trees,there was a positive relationship between J_S and the tree diameter at breast height,and this positive relationship became stronger as the transpiration demand increased.The spatial variations that caused large errors in E estimates(i.e.,up to 110.8 % when radial variation was ignored) had varied systematically with environmental factors systematic characteristics in relation to environmental factors.However,changes in these variations did not generate substantial errors in the E estimates.For our study periods,the differences in the daily E(E_D) calculated by ignoring radial,azimuthal and tree-to-tree variations and the measured E_D were fairly constant,especially when the daily vapor pressure deficit(D_D)was higher than 0.6 k Pa.These results imply that the effect of spatial variations changes on sap flow can be a minor source of error compared with spatial variations(radial,azimuthal and tree-to-tree variations) when considering E estimates.
文摘Based on the advantages of the wavelet to separate regional field and local anomalies in MATLAB environment,a high-precision regional-residual separation was finally realized. Analytical continuation and trend surface analysis are conventional methods for gravity anomaly separation. But the wavelet packet analysis in analyzing gravity data can make the gravity anomaly to be computed at a higher precision. In this paper,wavelet packet method is used to process gravity anomaly data obtained in Laos,and the separation result is good. Daubechies wavelet series has a higher precision in the wavelet packet.
基金"The 13th Five Year Plan"Regional Strategy Research Based on Resource and Environment Carrying Capacity and Innovation-driven.Major consulting projects of Scientific and Technical Strategy Consulting Institute,Chinese Academy of Sciences(Y02015005)
文摘Research on the relationship between national resource constraint-region types and environmental carrying capacity is essential for the continued development of Chinese industrialization and urbanization.Thus,utilizing a series of key indexes including the per-capita potential of available land resources,the per-capita potential of available water resources,the degree of environmental stress,and the degree of ecological restriction,a step-by-step,integrated measuring method is presented here to understand the constrained carrying elements of water and land resources as well as environment and ecology.Spatial differences are analyzed and area types classified at the county level across China.Results reveal that：（1）Almost 90%of China is strongly constrained by both resources and the environment,while nearly 50%of national territory is strongly constrained by two elements,especially in areas of intensive population and industry to the east of the Helan-Longmen Mountain line;（2）Densely populated areas of eastern and central China,as well as on the Tibetan Plateau,are strongly constrained by a shortage of land resources,while North China,the northwest,northeast,the Sichuan basin,and some southern cities are experiencing strong constraints because of water shortages.In contrast,the North China plain,the Yangtze River delta,northern Jiangsu,Sichuan province,Chongqing municipality,Guizhou and Guangxi provinces,the northeast plain,and the northern Loess Plateau are constrained by high levels of environmental stress.Areas of China that are strongly ecologically constrained tend to be concentrated to the southwest of the Tianshan-Dabie Mountain line,as well as in the northeast on the Loess Plateau,in the Alashan of Inner Mongolia,in northeast China,and in the northern Jiangsu coastal area;（3）Constraints on national resources and environmental carrying capacity are diverse and cross-cut China,meanwhile,multi-element spatial distribution does reveal a degree of relative centralization.With the exception of the Tibetan Plateau which is resources-ecological constraint,other areas subject to cross constraints are mainly concentrated to the east of the Helan-Longmen Mountain line.
文摘By analyzing and comparing the existing methods for the division of urban economic region, this paper supplemented and developed the breaking point theory. In this model, put forward for the first time using ＂the space-time distance＂ to replace ＂the space- linear distance＂ and ＂the city comprehensiveness quality- fuzzy comprehensive assessment Index＂ to ＂the urban population or GDP＇. Set up the algorithm of including ＂the space- time distance＂ and the city radiation scope changed with the changes of traffic conditions. Thus has realized ＂dynamically＂ tracing of the city radiation scope influenced by the traffic conditions. Taking Yichang city as an example, the paper analyzed the city function localization in the times of new traffic environments. Because China＇s cities are at the times of the traffic great changes, therefore, the method and the main conclusions of this paper have some methodology guiding sense to the majority cities of deffernt country to re-position.
基金supported by the Fundamental Research Funds for the Central Universities (Grant No. CUGL150812)the National Natural Science Foundation of China (Grant No. 41330103)the Programme of Introducing Talents of Discipline to Universities Project (Grant No. B08030)
文摘Glycerol dialkyl glycerol tetraethers(GDGTs) in lake sediments are useful biomarkers for the continental paleoclimatic reconstruction. However, the environmental controls on the distribution of these compounds, in particular the 6-methyl isomers of bacterial branched GDGTs(bGDGTs), in the lakes with contrasting pH, are still unknown, hindering their application for paleo-reconstructions. Here, we investigated the environmental impacts on the distribution of GDGTs in 17 alkaline lakes and 1 acid lake in China. It was found that the dissolved oxygen content in water column may have an impact on the distribution of archaeal isoprenoid GDGTs(iGDGTs) by causing the change in archaeal communities. The ratio of GDGT-0/crenarchaeol increases with decreasing oxygen content, indicating that the relative abundance of anaerobic methanogenic archaea or Miscellaneous Crenarchaeotic Group(MCG) vs. aerobic Thaumarchaeota is controlled by the oxygen content dissolved in water of these lakes. Thaumarchaeota are likely to contribute only a small proportion of iGDGTs in the relatively oxygen-depleted lakes, and thus TEX_(86) is not suitable for the reconstruction of the surface temperature of these lakes. The abundance ratio of iGDGTs to bGDGTs(R_(i/b)) appears to show no relationship with water pH in all the lakes, but exhibits a significant positive correlation with the water depth of the acid Lake Qinghai in Tengchong. As expected, the methylation degree of bGDGTs(MBT′) was found to correlate with both mean annual air temperature(MAT) and water pH, and the cyclization degree of bGDGTs(CBT) correlates only with water pH in these lakes. However, the MBT′_(5ME), an index to measure the methylation degree of 5-methyl bGDGTs, exhibits no relationship with MAT, whereas MBT′_(6ME), the methylation degree of 6-methyl bGDGTs, was found to correlate significantly with MAT. This is opposite to the situation observed in the global soils, pointing to a different adaptation of b GDGT-producing bacteria to environmental variables or different microbial sources of bGDGTs in these lakes. The relative abundance of 6- vs. 5-methyl bGDGTs is controlled by pH in these lakes, similar to that observed in worldwide soils. Hence, the isomer ratio(IR) of 6-methyl bGDGTs or CBT′ can be used as a proxy for water pH, although they might be influenced by other environmental factors including temperature in the lakes with a narrow range of pH.
文摘Individual behavioral variation is ubiquitous across taxa and important to understand if we wish to fully use beha- vioral data to understand the ecology and evolution of organisms. Only recently have studies of individual variation in dispersal behavior become a focus of research. A better understanding of individual variation in dispersal behavior is likely to improve our understanding of population dynamics. In particular, the dynamics of critically small populations （endangered species） and large populations （pest species） may be driven by unique dispersal variants. Here we documented individual variation in the ballooning dispersal behavior of Western black widow spiderlings Latrodectus hesperus, an urban pest species found in superabundant in- festations throughout cities of the desert Southwest USA. We found a great deal of family-level variation in ballooning dispersal, and this variation was highly consistent （repeatable） across time. Maternal egg investment was a poor predictor of this ballooning dispersal. Instead, we show that spiderlings reared in isolation are significantly slower to disperse than spiderlings raised in a more natural setting surrounded by full siblings. Thus, our study examines a widespread but poorly understood dispersal behavior （ballooning）, and suggests urban pest population dynamics are likely driven by the interaction of variation in individuals, families and social environments
