Great changes of ecological environment have taken place in Tarim River Basin of continental river basin in arid zone since last 5 decades.As a result, a series of characteristics that are not stability appeared.With ...Great changes of ecological environment have taken place in Tarim River Basin of continental river basin in arid zone since last 5 decades.As a result, a series of characteristics that are not stability appeared.With regard to the natural conditions and artificial interference, 20 complex factors of water resource system, land source system, vegetation resource system and environment system (esp.desertification state) are chosen to analyze the ecological fragility.Through establishment of indicator system of ecological fragility assessment and classification standard, based on the arithmetic logarithm processing, ecological fragility index (EFI) is built up.The results are as follows: the EFI values of source stream area including Aksu River Basin, Yerkant River Basin, Hetian River Basin and main stream including upper reaches, middle reaches and lower reaches of Tarim River Basin are 0.08, 0.23, 0.32, 0.25, 0.53 and 0.87 respectively.The degrees of ecological fragility belong to slight fragility, medium fragility and extreme fragility in Aksu River Basin, middle and lower reaches of Tarim River respectively in addition to general fragility in other three sections.展开更多
The Lhasa River Basin is one of the typical distribution regions of alpine wetlands on the Tibetan Plateau. It is very important to get a better understanding of the background and characteristics of alpine wetland fo...The Lhasa River Basin is one of the typical distribution regions of alpine wetlands on the Tibetan Plateau. It is very important to get a better understanding of the background and characteristics of alpine wetland for monitoring, protection and utilization. Wetland construction and distribution in the basin were analyzed based on multi-source data including field investigation data, CBERS remote sensing data and other thematic data provided by 3S technology. The results are （1） the total area of wetlands is 209,322.26 hm^2, accounting for 6.37% of the total land area of the basin. The wetlands are mainly dominated by natural wetland, with artificial wetland occupying only 1.09% of the wetland area; marsh wetland is the principal part of natural wetland, dominated by Kobresia littledalei swampy meadow which is distributed in the river source area and upstream of Chali, Damshung and Medro Gongkar counties. The ratio and type of wetlands in different counties differ significantly, which are widely distributed in Chali and Damshung counties （accounting for 62% of the total wetland area）. （2） The concentrated vertical distribution of wetlands is at an elevation of 3600-5100 m The wetlands are widely distributed throughout the Yarlung Zangbo River Valley from river source to river mouth into the Yarlung Zangbo River. Marsh wetland is dominant in the source area and upstream of the river, with the mosaic distribution of lakes, Kobresia litUedalei and Carex moorcroftii swampy meadow, shrubby swamp and river; as for the middle-down streams, the primary types are river wetland and flooded wetland. The distribution is in a mosaic pattern of river, Kobresia humilis and Carex moorcroftii swampy meadow, Phragmites australis and subordinate grass marsh, flooded wetland and artificial wetland.展开更多
文摘Great changes of ecological environment have taken place in Tarim River Basin of continental river basin in arid zone since last 5 decades.As a result, a series of characteristics that are not stability appeared.With regard to the natural conditions and artificial interference, 20 complex factors of water resource system, land source system, vegetation resource system and environment system (esp.desertification state) are chosen to analyze the ecological fragility.Through establishment of indicator system of ecological fragility assessment and classification standard, based on the arithmetic logarithm processing, ecological fragility index (EFI) is built up.The results are as follows: the EFI values of source stream area including Aksu River Basin, Yerkant River Basin, Hetian River Basin and main stream including upper reaches, middle reaches and lower reaches of Tarim River Basin are 0.08, 0.23, 0.32, 0.25, 0.53 and 0.87 respectively.The degrees of ecological fragility belong to slight fragility, medium fragility and extreme fragility in Aksu River Basin, middle and lower reaches of Tarim River respectively in addition to general fragility in other three sections.
基金The National Key Technology Research and Development Program,No.2007BAC06B03National Basic Research Program of China,No.2005CB422000
文摘The Lhasa River Basin is one of the typical distribution regions of alpine wetlands on the Tibetan Plateau. It is very important to get a better understanding of the background and characteristics of alpine wetland for monitoring, protection and utilization. Wetland construction and distribution in the basin were analyzed based on multi-source data including field investigation data, CBERS remote sensing data and other thematic data provided by 3S technology. The results are （1） the total area of wetlands is 209,322.26 hm^2, accounting for 6.37% of the total land area of the basin. The wetlands are mainly dominated by natural wetland, with artificial wetland occupying only 1.09% of the wetland area; marsh wetland is the principal part of natural wetland, dominated by Kobresia littledalei swampy meadow which is distributed in the river source area and upstream of Chali, Damshung and Medro Gongkar counties. The ratio and type of wetlands in different counties differ significantly, which are widely distributed in Chali and Damshung counties （accounting for 62% of the total wetland area）. （2） The concentrated vertical distribution of wetlands is at an elevation of 3600-5100 m The wetlands are widely distributed throughout the Yarlung Zangbo River Valley from river source to river mouth into the Yarlung Zangbo River. Marsh wetland is dominant in the source area and upstream of the river, with the mosaic distribution of lakes, Kobresia litUedalei and Carex moorcroftii swampy meadow, shrubby swamp and river; as for the middle-down streams, the primary types are river wetland and flooded wetland. The distribution is in a mosaic pattern of river, Kobresia humilis and Carex moorcroftii swampy meadow, Phragmites australis and subordinate grass marsh, flooded wetland and artificial wetland.
