The method was developed for a Range Management Handbook of Kenya and the pre-liminary results published 1991. Now it is improved to a stage ready for international discus-sion.1. Main moisture Zones are defined by a ...The method was developed for a Range Management Handbook of Kenya and the pre-liminary results published 1991. Now it is improved to a stage ready for international discus-sion.1. Main moisture Zones are defined by a specified sum of monthly moistureindices:展开更多
As a main component in water balance, evapotranspiration is of great importance for water saving and irrigation-measure making, especially in arid or semiarid regions. Although studies of evapotranspiration have been ...As a main component in water balance, evapotranspiration is of great importance for water saving and irrigation-measure making, especially in arid or semiarid regions. Although studies of evapotranspiration have been conducted for a long time, studies concentrated on oasis-desert transition zone are very limited. On the basis of the meteorological data and other parameters（e.g. leaf area index（LAI）） of an oasis-desert transition zone in the middle stream of Heihe River from 2005 to 2011, this paper calculated both reference（ET0） and actual evapotranspiration（ETc） using FAO56 Penman-Monteith and Penman-Monteith models, respectively. In combination with pan evaporation（Ep） measured by E601 pan evaporator, four aspects were analyzed：（1） ET0 was firstly verified by Ep;（2） Characteristics of ET0 and ETc were compared, while the influencing factors were also analyzed;（3） Since meteorological data are often unavailable for estimating ET0 through FAO56 Penman-Monteith model in this region, pan evaporation coefficient（Kp） is very important when using observed Ep to predict ET0. Under this circumstance, an empirical formula of Kp was put forward for this region;（4） Crop coefficient（Kc）, an important index to reflect evapotranspiration, was also analyzed. Results show that mean annual values of ET0 and ETc were 840 and 221 mm, respectively. On the daily bases, ET0 and ETc were 2.3 and 0.6 mm/d, respectively. The annual tendency of ET0 and ETc was very similar, but their amplitude was obviously different. The differences among ET0 and ETc were mainly attributed to the different meteorological variables and leaf area index. The calculated Kc was about 0.25 and showed little variation during the growing season, indicating that available water（e.g. precipitation and irrigation） of about 221 mm/a was required to keep the water balance in this region. The results provide an comprehensive analysis of evapotranspiration for an oasis-desert transition zone in the middle stream of Heihe River, which was seldom reported before.展开更多
Livestock ranching is one of the main productive activities in arid regions of the world.Grazing produces changes in animal as well as plant communities(e.g.richness,abundance and species dominance relationships).Ants...Livestock ranching is one of the main productive activities in arid regions of the world.Grazing produces changes in animal as well as plant communities(e.g.richness,abundance and species dominance relationships).Ants are good biological indicators due to the environmental fidelity of some of their community parameters.We described the functional structure of the ant community in the central Monte of Mendoza,Argentina,and examined the effect of grazing using richness,diversity and the functional group scheme.We used pitfall traps to sample ants at a reserve with 30-year cattle exclusion and at an adjacent ranch.Eleven of the 27 recorded species showed significant differences in their abundance and two species were absent at the ranch.While richness and diversity did not reflect these differences,functional groups did.Hot Climate Specialists were more abundant at the ranch while Cryptic Species and Generalized Myrmicinae increased at the reserve.This study supports the utility of the functional group scheme to study the effects of grazing disturbance in ant communities of arid regions.展开更多
In this paper, the concepts and principles of mountain-oasis-desert system (MODS) are put forward according to the natural geographical situations in arid zone of western china. The spatiotemporal characteristics and ...In this paper, the concepts and principles of mountain-oasis-desert system (MODS) are put forward according to the natural geographical situations in arid zone of western china. The spatiotemporal characteristics and dynamic changes of typical MODS, the process of material circulation, energy transform and information transmission among MODS and the mechanism of MODS interaction and symbiosis are analyzed. The foundation and frame of the coupling type are determined by landform types and climate characteristics: the spatial pattern of the coupling type is determined by the hydrological characteristics; the vegetation type reflects the appearance of the coupling type; the soil state restricts the function of the coupling type and the human activities influence the development course of the coupling type. Interface course of MODS is closely related to such medium as water, soil, air, etc., and water is the major medium during the course of material circulation, energy transform and information transmission. The disorder of water salt, water heat and water land restricts the stability of water ecosystem.展开更多
文摘The method was developed for a Range Management Handbook of Kenya and the pre-liminary results published 1991. Now it is improved to a stage ready for international discus-sion.1. Main moisture Zones are defined by a specified sum of monthly moistureindices:
基金founded by the National Natural Science Foundation of China (40930634, 41125002)
文摘As a main component in water balance, evapotranspiration is of great importance for water saving and irrigation-measure making, especially in arid or semiarid regions. Although studies of evapotranspiration have been conducted for a long time, studies concentrated on oasis-desert transition zone are very limited. On the basis of the meteorological data and other parameters（e.g. leaf area index（LAI）） of an oasis-desert transition zone in the middle stream of Heihe River from 2005 to 2011, this paper calculated both reference（ET0） and actual evapotranspiration（ETc） using FAO56 Penman-Monteith and Penman-Monteith models, respectively. In combination with pan evaporation（Ep） measured by E601 pan evaporator, four aspects were analyzed：（1） ET0 was firstly verified by Ep;（2） Characteristics of ET0 and ETc were compared, while the influencing factors were also analyzed;（3） Since meteorological data are often unavailable for estimating ET0 through FAO56 Penman-Monteith model in this region, pan evaporation coefficient（Kp） is very important when using observed Ep to predict ET0. Under this circumstance, an empirical formula of Kp was put forward for this region;（4） Crop coefficient（Kc）, an important index to reflect evapotranspiration, was also analyzed. Results show that mean annual values of ET0 and ETc were 840 and 221 mm, respectively. On the daily bases, ET0 and ETc were 2.3 and 0.6 mm/d, respectively. The annual tendency of ET0 and ETc was very similar, but their amplitude was obviously different. The differences among ET0 and ETc were mainly attributed to the different meteorological variables and leaf area index. The calculated Kc was about 0.25 and showed little variation during the growing season, indicating that available water（e.g. precipitation and irrigation） of about 221 mm/a was required to keep the water balance in this region. The results provide an comprehensive analysis of evapotranspiration for an oasis-desert transition zone in the middle stream of Heihe River, which was seldom reported before.
基金partially funded by a grant from the National Council of Research (Argentina) Number 4678 for the project"Insect Biodiversity of the Monte"
文摘Livestock ranching is one of the main productive activities in arid regions of the world.Grazing produces changes in animal as well as plant communities(e.g.richness,abundance and species dominance relationships).Ants are good biological indicators due to the environmental fidelity of some of their community parameters.We described the functional structure of the ant community in the central Monte of Mendoza,Argentina,and examined the effect of grazing using richness,diversity and the functional group scheme.We used pitfall traps to sample ants at a reserve with 30-year cattle exclusion and at an adjacent ranch.Eleven of the 27 recorded species showed significant differences in their abundance and two species were absent at the ranch.While richness and diversity did not reflect these differences,functional groups did.Hot Climate Specialists were more abundant at the ranch while Cryptic Species and Generalized Myrmicinae increased at the reserve.This study supports the utility of the functional group scheme to study the effects of grazing disturbance in ant communities of arid regions.
文摘In this paper, the concepts and principles of mountain-oasis-desert system (MODS) are put forward according to the natural geographical situations in arid zone of western china. The spatiotemporal characteristics and dynamic changes of typical MODS, the process of material circulation, energy transform and information transmission among MODS and the mechanism of MODS interaction and symbiosis are analyzed. The foundation and frame of the coupling type are determined by landform types and climate characteristics: the spatial pattern of the coupling type is determined by the hydrological characteristics; the vegetation type reflects the appearance of the coupling type; the soil state restricts the function of the coupling type and the human activities influence the development course of the coupling type. Interface course of MODS is closely related to such medium as water, soil, air, etc., and water is the major medium during the course of material circulation, energy transform and information transmission. The disorder of water salt, water heat and water land restricts the stability of water ecosystem.
