Ecosystem risk is a new concept in understanding environmental problems. It is important to study and develop quantitative methods for regional ecosystem risk analysis. In this study, some new indicators and methods f...Ecosystem risk is a new concept in understanding environmental problems. It is important to study and develop quantitative methods for regional ecosystem risk analysis. In this study, some new indicators and methods for measuring oasis ecosystem risk were established using reliability theory. These indicators are linked to water resource, which is the key restricting factor in arid area oasis ecosystems. They have clear meanings and can also be compared in different arid area oases. A case study in the Liangzhou oasis of the Shiyang River Basin in China shows how to calculate these ecosystem risk indicators. The results of the case study are as follows： the reliability indicator, risk indicator, stability indicator, and integrated loss indicator of the Liangzhou oasis are 0.686, 0.314, 0.743, and 0.301, respectively. This means that the reliability degree of the oasis＇s ecosystem safety is 68.6%; the degree of risk that it is unsafe is 31.4%; the stability degree is 74.3%; and 30.1% of the oasis＇s area is supported by over-exploiting underground water and damaging the lower reaches of the ecosystem. This result can be used as a guide in controlling and managing ecosystem risk in the research area.展开更多
On the basis of the study on areal differentiation of the natural environment of oasis agriculture ecosystems in the Shiyang River Basin, this paper comparatively analyzes the natural productivities, water economic be...On the basis of the study on areal differentiation of the natural environment of oasis agriculture ecosystems in the Shiyang River Basin, this paper comparatively analyzes the natural productivities, water economic benefits, production efficiency, ecological stabilities and developmental conditions of the Wuwei Oasis agricultural ecosystem in the middle reaches of the river basin and the Minqin Oasis agricultural ecosystem in the lower reaches. Under a same management level and investment of . material and energy, primary productiveness and economic benefits of the former are higher than those of the latter. Construction directions of Wuwei and Minqin oases should be different in order to alleviate the water- use contradiction between the middle and lower reaches. The construction objective of Wuwei Oasis should be efficient irrigated farming production system and Minqin Oasis should become a mixed forestry-pastoral-farming ecosystem taking ecological protection as its major function.展开更多
Knowledge of soil carbon（C） distribution and its relationship with the environment can improve our understanding of its biogeochemical cycling and help to establish sound regional models of C cycling. However, such ...Knowledge of soil carbon（C） distribution and its relationship with the environment can improve our understanding of its biogeochemical cycling and help to establish sound regional models of C cycling. However, such knowledge is limited in environments with complex landscape configurations. In this study, we investigated the vertical distribution and storage of soil organic carbon（SOC） and soil inorganic carbon（SIC） in the 10 representative landscapes（alpine meadow, subalpine shrub and meadow, mountain grassland, mountain forest, typical steppe, desert steppe, Hexi Corridor oases cropland, Ruoshui River delta desert, Alxa Gobi desert, and sandy desert） with contrasting bioclimatic regimes in the Heihe River Basin, Northwest China. We also measured the 87 Sr/86 Sr ratio in soil carbonate to understand the sources of SIC because the ratio can be used as a proxy in calculating the contribution of pedogenic inorganic carbon（PIC） to total SIC. Our results showed that SOC contents generally decreased with increasing soil depth in all landscapes, while SIC contents exhibited more complicated variations along soil profiles in relation to pedogenic processes and parent materials at the various landscapes. There were significant differences of C stocks in the top meter among different landscapes, with SOC storage ranging from 0.82 kg C/m^2 in sandy desert to 50.48 kg C/m^2 in mountain forest and SIC storage ranging from 0.19 kg C/m^2 in alpine meadow to 21.91 kg C/m^2 in desert steppe. SIC contributed more than 75% of total C pool when SOC storage was lower than 10 kg C/m^2, and the proportion of PIC to SIC was greater than 70% as calculated from Sr isotopic ratio, suggesting the critical role of PIC in the C budget of this region. The considerable variations of SOC and SIC in different landscapes were attributed to different pedogenic environments resulted from contrasting climatic regimes, parent materials and vegetation types. This study provides an evidence for a general trade-off pattern between SOC and SIC, showing the compensatory effects of environmental conditions（especially climate） on SOC and SIC formation in these landscapes. This is largely attributed to the fact that the overall decrease in temperature and increase in precipitation from arid deserts to alpine mountains simultaneously facilitate the accumulation of SOC and depletion of SIC.展开更多
The Lower Mekong River basin (LMB) covers the lower part of the Mekong river basin, including Laos, Thailand, Cambodia and Vietnam. Due to numerous pressures from high population growth and intensive hydropower develo...The Lower Mekong River basin (LMB) covers the lower part of the Mekong river basin, including Laos, Thailand, Cambodia and Vietnam. Due to numerous pressures from high population growth and intensive hydropower development, the LMB has been facing significant challenges concerning its biodiversity and ecosystem. In 2017, Mekong River Commission (MRC), an intergovernmental organisation founded in 1995 among LMB countries, established the Council Study, which analysed the impacts of water development scenarios concerning the environmental, socioeconomic aspects of the LMB. This paper explores the nature of risks to the LMB water development and subsequently evaluates LMB’s water development scenarios described in the Council Study by using a multi-criteria decision analysis (MCDA) method. MCDA method has been widely applied in the field of water resource management in order to assist the decision-making process by systematically evaluating a certain number of alternatives against well-selected criteria through a preference rating scheme. By implementing a risk-based comprehensive assessment of the LMB transboundary water, this study provides insights into the impacts of the increasing risks to the ecosystem and human beings on the water development of the basin over time, which assists to change the awareness and the perspective toward humans’ risks and transboundary river ecosystem of decision-makers. This paper provides valuable recommendations for MRC to improve their policy concerning benefit-sharing scheme, water planning and risk mitigation strategies.展开更多
Shrub is an important factor on structuring ground arthropod communities in desert ecosystems. In this study, in order to determine how shrubs and their species influence ground arthropod distribution patterns in a sa...Shrub is an important factor on structuring ground arthropod communities in desert ecosystems. In this study, in order to determine how shrubs and their species influence ground arthropod distribution patterns in a sandy desert scrubland dominated by two different shrub species, Calligonum mongolicum and Nitraria sphaerocarpa, the ground arthropods were sampled with pitfall traps during spring, summer and autumn. At the community level, total arthropod abundance was shown to be significantly higher under shrubs than in intershrub bare areas in spring; similar patterns occurred in terms of the richness of arthropod groups in the spring and over three seasons, suggesting season-specific shrub presence effects on arthropod activity. In addition, more arthropods were found under N. sphaerocarpa shrubs than under C. rnongolicum shrubs in autumn, suggesting season-specific effects of shrub species of arthropod activity, whereas more arthropods taxa were captured under C. mongoIicum than N. sphaerocarpa. At the trophic group level, the abundances of predator and herbivore arthropods were significantly greater under shrubs than in intershrub bare habitats, whereas herbivore arthropods were more abundant under N. sphaerocarpa than C. rnongolicum, and an opposite rule was detected for predator arthropods At the family level, the mean abundances of Carabidae, Curculionidae, Gnaphosidae and Lycosidae were significantly higher in the shrub microhabitats than in the intershrub bare habitat, there was no significant difference between habitats on the mean abundances of Formicidae and Tenebrionidae. The study results suggested that shrub presence and shrub species variation are important determinants of ground arthropod assemblages in this desert ecosystem, but the responses of ar- thropods differed among trophic and taxonomic groups.展开更多
基金Project supported by the China Scholarship Council and the National Basic Research Program (973) of China (No. 2002CCA00300).
文摘Ecosystem risk is a new concept in understanding environmental problems. It is important to study and develop quantitative methods for regional ecosystem risk analysis. In this study, some new indicators and methods for measuring oasis ecosystem risk were established using reliability theory. These indicators are linked to water resource, which is the key restricting factor in arid area oasis ecosystems. They have clear meanings and can also be compared in different arid area oases. A case study in the Liangzhou oasis of the Shiyang River Basin in China shows how to calculate these ecosystem risk indicators. The results of the case study are as follows： the reliability indicator, risk indicator, stability indicator, and integrated loss indicator of the Liangzhou oasis are 0.686, 0.314, 0.743, and 0.301, respectively. This means that the reliability degree of the oasis＇s ecosystem safety is 68.6%; the degree of risk that it is unsafe is 31.4%; the stability degree is 74.3%; and 30.1% of the oasis＇s area is supported by over-exploiting underground water and damaging the lower reaches of the ecosystem. This result can be used as a guide in controlling and managing ecosystem risk in the research area.
文摘On the basis of the study on areal differentiation of the natural environment of oasis agriculture ecosystems in the Shiyang River Basin, this paper comparatively analyzes the natural productivities, water economic benefits, production efficiency, ecological stabilities and developmental conditions of the Wuwei Oasis agricultural ecosystem in the middle reaches of the river basin and the Minqin Oasis agricultural ecosystem in the lower reaches. Under a same management level and investment of . material and energy, primary productiveness and economic benefits of the former are higher than those of the latter. Construction directions of Wuwei and Minqin oases should be different in order to alleviate the water- use contradiction between the middle and lower reaches. The construction objective of Wuwei Oasis should be efficient irrigated farming production system and Minqin Oasis should become a mixed forestry-pastoral-farming ecosystem taking ecological protection as its major function.
基金supported by the National Natural Science Foundation of China(91325301,41130530,41371224,41601221)
文摘Knowledge of soil carbon（C） distribution and its relationship with the environment can improve our understanding of its biogeochemical cycling and help to establish sound regional models of C cycling. However, such knowledge is limited in environments with complex landscape configurations. In this study, we investigated the vertical distribution and storage of soil organic carbon（SOC） and soil inorganic carbon（SIC） in the 10 representative landscapes（alpine meadow, subalpine shrub and meadow, mountain grassland, mountain forest, typical steppe, desert steppe, Hexi Corridor oases cropland, Ruoshui River delta desert, Alxa Gobi desert, and sandy desert） with contrasting bioclimatic regimes in the Heihe River Basin, Northwest China. We also measured the 87 Sr/86 Sr ratio in soil carbonate to understand the sources of SIC because the ratio can be used as a proxy in calculating the contribution of pedogenic inorganic carbon（PIC） to total SIC. Our results showed that SOC contents generally decreased with increasing soil depth in all landscapes, while SIC contents exhibited more complicated variations along soil profiles in relation to pedogenic processes and parent materials at the various landscapes. There were significant differences of C stocks in the top meter among different landscapes, with SOC storage ranging from 0.82 kg C/m^2 in sandy desert to 50.48 kg C/m^2 in mountain forest and SIC storage ranging from 0.19 kg C/m^2 in alpine meadow to 21.91 kg C/m^2 in desert steppe. SIC contributed more than 75% of total C pool when SOC storage was lower than 10 kg C/m^2, and the proportion of PIC to SIC was greater than 70% as calculated from Sr isotopic ratio, suggesting the critical role of PIC in the C budget of this region. The considerable variations of SOC and SIC in different landscapes were attributed to different pedogenic environments resulted from contrasting climatic regimes, parent materials and vegetation types. This study provides an evidence for a general trade-off pattern between SOC and SIC, showing the compensatory effects of environmental conditions（especially climate） on SOC and SIC formation in these landscapes. This is largely attributed to the fact that the overall decrease in temperature and increase in precipitation from arid deserts to alpine mountains simultaneously facilitate the accumulation of SOC and depletion of SIC.
文摘The Lower Mekong River basin (LMB) covers the lower part of the Mekong river basin, including Laos, Thailand, Cambodia and Vietnam. Due to numerous pressures from high population growth and intensive hydropower development, the LMB has been facing significant challenges concerning its biodiversity and ecosystem. In 2017, Mekong River Commission (MRC), an intergovernmental organisation founded in 1995 among LMB countries, established the Council Study, which analysed the impacts of water development scenarios concerning the environmental, socioeconomic aspects of the LMB. This paper explores the nature of risks to the LMB water development and subsequently evaluates LMB’s water development scenarios described in the Council Study by using a multi-criteria decision analysis (MCDA) method. MCDA method has been widely applied in the field of water resource management in order to assist the decision-making process by systematically evaluating a certain number of alternatives against well-selected criteria through a preference rating scheme. By implementing a risk-based comprehensive assessment of the LMB transboundary water, this study provides insights into the impacts of the increasing risks to the ecosystem and human beings on the water development of the basin over time, which assists to change the awareness and the perspective toward humans’ risks and transboundary river ecosystem of decision-makers. This paper provides valuable recommendations for MRC to improve their policy concerning benefit-sharing scheme, water planning and risk mitigation strategies.
基金funded by one of National Basic Research Program of China (No. 2013CB429903)National Natural Science Foundation of China (Grant Nos. 41201248 and 31170496)
文摘Shrub is an important factor on structuring ground arthropod communities in desert ecosystems. In this study, in order to determine how shrubs and their species influence ground arthropod distribution patterns in a sandy desert scrubland dominated by two different shrub species, Calligonum mongolicum and Nitraria sphaerocarpa, the ground arthropods were sampled with pitfall traps during spring, summer and autumn. At the community level, total arthropod abundance was shown to be significantly higher under shrubs than in intershrub bare areas in spring; similar patterns occurred in terms of the richness of arthropod groups in the spring and over three seasons, suggesting season-specific shrub presence effects on arthropod activity. In addition, more arthropods were found under N. sphaerocarpa shrubs than under C. rnongolicum shrubs in autumn, suggesting season-specific effects of shrub species of arthropod activity, whereas more arthropods taxa were captured under C. mongoIicum than N. sphaerocarpa. At the trophic group level, the abundances of predator and herbivore arthropods were significantly greater under shrubs than in intershrub bare habitats, whereas herbivore arthropods were more abundant under N. sphaerocarpa than C. rnongolicum, and an opposite rule was detected for predator arthropods At the family level, the mean abundances of Carabidae, Curculionidae, Gnaphosidae and Lycosidae were significantly higher in the shrub microhabitats than in the intershrub bare habitat, there was no significant difference between habitats on the mean abundances of Formicidae and Tenebrionidae. The study results suggested that shrub presence and shrub species variation are important determinants of ground arthropod assemblages in this desert ecosystem, but the responses of ar- thropods differed among trophic and taxonomic groups.
