Taking Zhongba County, Angren County, Rikaze City located at the Upper and Middle Reaches of Yarlung Zangbo River as landscape units , this paper studied the difference of the landscape pattern under various degrees o...Taking Zhongba County, Angren County, Rikaze City located at the Upper and Middle Reaches of Yarlung Zangbo River as landscape units , this paper studied the difference of the landscape pattern under various degrees of human disturbance in the three areas. The results showed that： the three areas all reflected the same characteristic of landscape pattern in Qinghai-Tibet Plateau, the natural landscapes were in the absolute dominant position. However, from Zhangba to Rikaze, with human disturbance intensity increasing, anthropogenic features of landscapes became more and more outstanding, In Zhongba, the landscape structure appeared to be simpler with coarse grains and a less rich diversity, Conversely, in Rikaze, the landscape showed a complicated shape with finer grains and a relatively richer diversity, This reflected that the impact of human activities to natural landscape behaved a gradually-growing trend from the upper reach to the middle one of Yarlung Zangbo River Basin.展开更多
[Objective] Species composition and flora of vascular plants in the middle and upper reaches of the Yarlung Zangbo River were analyzed,to provide scientific basis for the estimation and protection of plant diversity,c...[Objective] Species composition and flora of vascular plants in the middle and upper reaches of the Yarlung Zangbo River were analyzed,to provide scientific basis for the estimation and protection of plant diversity,construction of ecological security shelter for the Tibetan Plateau.[Methods] In the middle and upper reaches of the Yarlung Zangbo River,quadrat (line transect) method was applied to investigate the phytocoenoses in sample plots,and relative literature was used to analyze the floristic composition and floristic element of vascular plants in the middle and upper reaches of the Yarlung Zangbo River.[Results]① There are 96 species (including subspecies and variations),69 genera of 35 vascular plant families,accounting for 16.83%,5.48%,1.66% and 11.63%,2.02%,0.31% of total vascular plant families,genera and species in Tibet and China.② There are 24 monotypic-genus families,accounting for 68.57% of the total family number in the local area;22 monotypic-species families,accounting for 62.86% of the total family number in the local area.Local flora shows the characteristics of ancient relict,such as Euphorbiaceae,Rubiaceae,Liliaceae and Ranunculaceae,they are all ancient primitive groups of the third flora and the fourth flora.③ Local vascular plant genera fall into 10 areal types and 8 variations.④ Temperate elements are much more than tropical elements,R/T is 0.19,indicating that vascular plants have typical temperate nature and residual tropical nature.There are only a few endemic genera,but more endemic species to the local area,and these species are closely related,of which there are some transitional species,indicating that local flora is too young to experience more differentiation and specialization.⑤ There are 24 Chinese endemic species,accounting for 25% of total number of species in the local area;among which there are 12 endemic species to Tibet,accounting for 50% of endemic species to China,12.5% of total number of species in the local area.Four key wild plant species are included in the second batch of national key protection.[Conclusions]① There are scarce plant groups in the local area.② Among the obvious advantages,single-genus (species) families possess the absolute advantage,and the flora has ancient origins.③ The local flora has diversified distribution types,and the complicated geographical elements.④ Temperate species possess obvious advantages,and the flora is young.⑤ Rich unique and rare species have high species diversity protection and research value.展开更多
Based on vegetation survey data and environmental data of the Yarlung Zangbo River Basin, we conducted a quantitative ecological analysis of the vegetation community composition and the relationship between species an...Based on vegetation survey data and environmental data of the Yarlung Zangbo River Basin, we conducted a quantitative ecological analysis of the vegetation community composition and the relationship between species and the environment in the study area. The results showed that 44 sampling sites and 68 plant species in the study area can be classified into seven subtypes: Artemisia minor + Stipa purpurea;Artemisia demissa + Stipa purpurea + Artemisia wellbyi;Kobresia pygmaea;Trikeraia hookeri;Sophora moorcroftiana + Cotoneaster multiflorus + Pennisetum centrasiaticum;Artemisia frigida;Potentilla fruticosa + Orinus thoroldii. Detrended correspondence analysis(DCA) indicated that both longitude and altitude play important roles in site and species distribution patterns. In addition, canonical correspondence analysis(CCA) revealed that in the upper and middle reaches of the Yarlung Zangbo River Basin, changes in temperature and precipitation caused by longitude are the main factors controlling the formation and transition of vegetation community types. Moreover, natural vegetation could be divided into three types: desert steppe community(source area), alpine steppe community(middle reaches region), and shrub community(confluence of Yarlung Zangbo River and Nyangqu River).展开更多
文摘Taking Zhongba County, Angren County, Rikaze City located at the Upper and Middle Reaches of Yarlung Zangbo River as landscape units , this paper studied the difference of the landscape pattern under various degrees of human disturbance in the three areas. The results showed that： the three areas all reflected the same characteristic of landscape pattern in Qinghai-Tibet Plateau, the natural landscapes were in the absolute dominant position. However, from Zhangba to Rikaze, with human disturbance intensity increasing, anthropogenic features of landscapes became more and more outstanding, In Zhongba, the landscape structure appeared to be simpler with coarse grains and a less rich diversity, Conversely, in Rikaze, the landscape showed a complicated shape with finer grains and a relatively richer diversity, This reflected that the impact of human activities to natural landscape behaved a gradually-growing trend from the upper reach to the middle one of Yarlung Zangbo River Basin.
基金Supported by National Key R&D Program of china(2016YFC0502006)Major Science and Technology Projects of Tibet(Z2016C01G01/02)
文摘[Objective] Species composition and flora of vascular plants in the middle and upper reaches of the Yarlung Zangbo River were analyzed,to provide scientific basis for the estimation and protection of plant diversity,construction of ecological security shelter for the Tibetan Plateau.[Methods] In the middle and upper reaches of the Yarlung Zangbo River,quadrat (line transect) method was applied to investigate the phytocoenoses in sample plots,and relative literature was used to analyze the floristic composition and floristic element of vascular plants in the middle and upper reaches of the Yarlung Zangbo River.[Results]① There are 96 species (including subspecies and variations),69 genera of 35 vascular plant families,accounting for 16.83%,5.48%,1.66% and 11.63%,2.02%,0.31% of total vascular plant families,genera and species in Tibet and China.② There are 24 monotypic-genus families,accounting for 68.57% of the total family number in the local area;22 monotypic-species families,accounting for 62.86% of the total family number in the local area.Local flora shows the characteristics of ancient relict,such as Euphorbiaceae,Rubiaceae,Liliaceae and Ranunculaceae,they are all ancient primitive groups of the third flora and the fourth flora.③ Local vascular plant genera fall into 10 areal types and 8 variations.④ Temperate elements are much more than tropical elements,R/T is 0.19,indicating that vascular plants have typical temperate nature and residual tropical nature.There are only a few endemic genera,but more endemic species to the local area,and these species are closely related,of which there are some transitional species,indicating that local flora is too young to experience more differentiation and specialization.⑤ There are 24 Chinese endemic species,accounting for 25% of total number of species in the local area;among which there are 12 endemic species to Tibet,accounting for 50% of endemic species to China,12.5% of total number of species in the local area.Four key wild plant species are included in the second batch of national key protection.[Conclusions]① There are scarce plant groups in the local area.② Among the obvious advantages,single-genus (species) families possess the absolute advantage,and the flora has ancient origins.③ The local flora has diversified distribution types,and the complicated geographical elements.④ Temperate species possess obvious advantages,and the flora is young.⑤ Rich unique and rare species have high species diversity protection and research value.
基金The 13th Five-year National Key Research and Development Program of China(2016YFC0502006)
文摘Based on vegetation survey data and environmental data of the Yarlung Zangbo River Basin, we conducted a quantitative ecological analysis of the vegetation community composition and the relationship between species and the environment in the study area. The results showed that 44 sampling sites and 68 plant species in the study area can be classified into seven subtypes: Artemisia minor + Stipa purpurea;Artemisia demissa + Stipa purpurea + Artemisia wellbyi;Kobresia pygmaea;Trikeraia hookeri;Sophora moorcroftiana + Cotoneaster multiflorus + Pennisetum centrasiaticum;Artemisia frigida;Potentilla fruticosa + Orinus thoroldii. Detrended correspondence analysis(DCA) indicated that both longitude and altitude play important roles in site and species distribution patterns. In addition, canonical correspondence analysis(CCA) revealed that in the upper and middle reaches of the Yarlung Zangbo River Basin, changes in temperature and precipitation caused by longitude are the main factors controlling the formation and transition of vegetation community types. Moreover, natural vegetation could be divided into three types: desert steppe community(source area), alpine steppe community(middle reaches region), and shrub community(confluence of Yarlung Zangbo River and Nyangqu River).
