Spatial and structural characteristics of plant communities in the steppe ecosystems of the Baikal region, Russian Federation have been researched in connection with climate change and grazing. The present study, base...Spatial and structural characteristics of plant communities in the steppe ecosystems of the Baikal region, Russian Federation have been researched in connection with climate change and grazing. The present study, based on a total of 15 typical steppe sampling plots, investigated above-ground biomass （AGB）, below-ground biomass （BGB）, total biomass （TB） and root：shoot ratios （R：S） and their relationships with climatic factors and grazing. All biomass components varied widely depending on the climatic parameters and the degree of grazing affected transformation. A strong negative correlation between mean annual temperature （MAT） and total plant biomass was revealed for all study area. Mean annual precipitation （MAP） signiifcantly affected communities productivity increasing only in the south of the region. Due to the large and mountainous territory, the inlfuence of latitude and elevation （mountain） factors on the components of the biomass were studied. Although all studied plant steppe communities were transformed by uncontrolled grazing, their productivity is signiifcantly reduced only at plots with maximum digression. Vegetation shift is an indicator of climate change, as well as providing a diagnostic tool to build predictive models. Based on the complex index of effective precipitation, it was revealed that at the end of last century in the steppes of the Baikal region the structural and production processes will be affected by an arid climate trend.展开更多
During last decades, new trends appeared in the ecotones of the upper boundary of forests at the ridges surroundingLakeBaikal(Khamar-Daban and Baikal’sky Ridge): ones to advance of wood species (Pinus sibirica Du Tou...During last decades, new trends appeared in the ecotones of the upper boundary of forests at the ridges surroundingLakeBaikal(Khamar-Daban and Baikal’sky Ridge): ones to advance of wood species (Pinus sibirica Du Tour, Abies sibirica Ledeb., Larix sibirica Ledeb., Larix dahurica Lawson) out of timber stands into the area of subgoltsy with Pinus pumila (Pallas) Regel. up to mountain tundras. In average, this is from 100 to 200 - 300 meters (maximum up to500 m) in linear distance from the margin of dense timber stand. A burst of forests renewal occurred in 1989-1995, it resulted probably from a high productivity of the seeds of wood species due to warmer winters in 1980ies-1990ies which favoured the formation of favourable climate-edaphic conditions for the development of forest communities above the forests boundary on the ridges surrounding Lake Baikal.展开更多
The results of studies of the peculiarities of formation of phytocenoses in environments contact sites of the western and eastern coasts of the Lake Baikal has been showed in this paper. On the base of geobotanic prof...The results of studies of the peculiarities of formation of phytocenoses in environments contact sites of the western and eastern coasts of the Lake Baikal has been showed in this paper. On the base of geobotanic profiling combined with soil one, the structure and dynamics of phytocenoses forming under the conditions of mutual development of light-coniferous taiga forest and of extra zonal steppes. Edaphic conditions and placement of phytocenoses are main trigger factors determining the ways of plant cover development in this part of Lake Baikal basin. We discuss the characteristics properties inherent in the linkage of the dynamics and spatial variability of the vegetation with the change of climate in the Baikal region. The regional conditions of the physiogeographic environment had given rise to structurally highly contrasting plant communities in this region. The increase in yearly mean summertime amounts of rainfall, combined with the rise of yearly mean winter temperatures over the last years were conducive to changes in the spatial structure of vegetation. The boundary between the types of vegetation undergoes smoothing. The upper boundary of forest is altered because of changes of the environment that are responsible for the zonality and properties of vertical zonality of the vegetation on the mountains surrounding Lake Baikal. Changes in the vegetation serve as indicators of climate change as well as providing diagnostic tools for the genesis of the Baikal region’s natural environment.展开更多
利用1958—2001年NCEP/NCAR再分析资料,探讨了热带太平洋(100°E^60°W,10°S^10°N)10 m风场的时空变化特征及其与东亚大气环流的可能联系。结果表明:1)热带太平洋风场异常存在两种主模态,第一模态对应中西太平洋一致...利用1958—2001年NCEP/NCAR再分析资料,探讨了热带太平洋(100°E^60°W,10°S^10°N)10 m风场的时空变化特征及其与东亚大气环流的可能联系。结果表明:1)热带太平洋风场异常存在两种主模态,第一模态对应中西太平洋一致的西(东)风异常,关于赤道呈准对称分布,与ENSO(El Nio-Southern Oscillation)暖(冷)位相时风场的分布对应;第二模态则关于赤道呈反对称分布,西北太平洋存在显著的反气旋(气旋)式环流,中太平洋异常西风不再位于赤道上,而是南移到了10°S左右,对应ENSO暖(冷)位相向相反位相转换时的风场分布特征。2)两模态时间系数的主振荡周期不同,与ENSO循环的位相关系也不同。研究发现,当两模态呈正(负)位相分布时,贝加尔湖南侧(South to Lake Baikal,SLB)容易发生持续的高压(低压)异常环流。3)两模态与SLB异常环流的联系途径不同。第一模态正位相对应热带中东太平洋大范围暖海温引起的二极型Walker环流异常,SLB异常高压不仅能通过东亚沿岸北风和南海低槽的作用促进第一模态的前期发展,还对其后期维持起重要作用。负位相时,情况相反。该环流系统既与热带中东太平洋大范围垂直运动有关,还与邻近的中国东南沿海低层异常辐合有关;第二模态则对应热带西太平洋及东印度洋为主、大西洋为辅的暖海温引起的热带四极型Walker环流异常。此时热带西太平洋到东印度洋局地偏强的经圈Hadley环流可能是SLB异常环流维持的主要原因。展开更多
基金supported by the joint Russian-Chinese project of RFBR-NSFC(13-04-91181-ГФЕН_а)the International Science&Technology Cooperation Program of China(2013DFR30760+2 种基金CR17-13)the National Basic Research Program of China(2014CB138806)supported by projects No.4.13(Structural and Dynamic Changes in Ecosystemsin Southern Siberia and Complex Indication of the Processes of Desertification,Predictive Models and Monitoring Systems) and No.30.21(The Inventory of the Biological Diversity of Transbaikalia Subarid Regions) financed by the Russian Academy of Sciences
文摘Spatial and structural characteristics of plant communities in the steppe ecosystems of the Baikal region, Russian Federation have been researched in connection with climate change and grazing. The present study, based on a total of 15 typical steppe sampling plots, investigated above-ground biomass （AGB）, below-ground biomass （BGB）, total biomass （TB） and root：shoot ratios （R：S） and their relationships with climatic factors and grazing. All biomass components varied widely depending on the climatic parameters and the degree of grazing affected transformation. A strong negative correlation between mean annual temperature （MAT） and total plant biomass was revealed for all study area. Mean annual precipitation （MAP） signiifcantly affected communities productivity increasing only in the south of the region. Due to the large and mountainous territory, the inlfuence of latitude and elevation （mountain） factors on the components of the biomass were studied. Although all studied plant steppe communities were transformed by uncontrolled grazing, their productivity is signiifcantly reduced only at plots with maximum digression. Vegetation shift is an indicator of climate change, as well as providing a diagnostic tool to build predictive models. Based on the complex index of effective precipitation, it was revealed that at the end of last century in the steppes of the Baikal region the structural and production processes will be affected by an arid climate trend.
文摘During last decades, new trends appeared in the ecotones of the upper boundary of forests at the ridges surroundingLakeBaikal(Khamar-Daban and Baikal’sky Ridge): ones to advance of wood species (Pinus sibirica Du Tour, Abies sibirica Ledeb., Larix sibirica Ledeb., Larix dahurica Lawson) out of timber stands into the area of subgoltsy with Pinus pumila (Pallas) Regel. up to mountain tundras. In average, this is from 100 to 200 - 300 meters (maximum up to500 m) in linear distance from the margin of dense timber stand. A burst of forests renewal occurred in 1989-1995, it resulted probably from a high productivity of the seeds of wood species due to warmer winters in 1980ies-1990ies which favoured the formation of favourable climate-edaphic conditions for the development of forest communities above the forests boundary on the ridges surrounding Lake Baikal.
文摘The results of studies of the peculiarities of formation of phytocenoses in environments contact sites of the western and eastern coasts of the Lake Baikal has been showed in this paper. On the base of geobotanic profiling combined with soil one, the structure and dynamics of phytocenoses forming under the conditions of mutual development of light-coniferous taiga forest and of extra zonal steppes. Edaphic conditions and placement of phytocenoses are main trigger factors determining the ways of plant cover development in this part of Lake Baikal basin. We discuss the characteristics properties inherent in the linkage of the dynamics and spatial variability of the vegetation with the change of climate in the Baikal region. The regional conditions of the physiogeographic environment had given rise to structurally highly contrasting plant communities in this region. The increase in yearly mean summertime amounts of rainfall, combined with the rise of yearly mean winter temperatures over the last years were conducive to changes in the spatial structure of vegetation. The boundary between the types of vegetation undergoes smoothing. The upper boundary of forest is altered because of changes of the environment that are responsible for the zonality and properties of vertical zonality of the vegetation on the mountains surrounding Lake Baikal. Changes in the vegetation serve as indicators of climate change as well as providing diagnostic tools for the genesis of the Baikal region’s natural environment.
文摘利用1958—2001年NCEP/NCAR再分析资料,探讨了热带太平洋(100°E^60°W,10°S^10°N)10 m风场的时空变化特征及其与东亚大气环流的可能联系。结果表明:1)热带太平洋风场异常存在两种主模态,第一模态对应中西太平洋一致的西(东)风异常,关于赤道呈准对称分布,与ENSO(El Nio-Southern Oscillation)暖(冷)位相时风场的分布对应;第二模态则关于赤道呈反对称分布,西北太平洋存在显著的反气旋(气旋)式环流,中太平洋异常西风不再位于赤道上,而是南移到了10°S左右,对应ENSO暖(冷)位相向相反位相转换时的风场分布特征。2)两模态时间系数的主振荡周期不同,与ENSO循环的位相关系也不同。研究发现,当两模态呈正(负)位相分布时,贝加尔湖南侧(South to Lake Baikal,SLB)容易发生持续的高压(低压)异常环流。3)两模态与SLB异常环流的联系途径不同。第一模态正位相对应热带中东太平洋大范围暖海温引起的二极型Walker环流异常,SLB异常高压不仅能通过东亚沿岸北风和南海低槽的作用促进第一模态的前期发展,还对其后期维持起重要作用。负位相时,情况相反。该环流系统既与热带中东太平洋大范围垂直运动有关,还与邻近的中国东南沿海低层异常辐合有关;第二模态则对应热带西太平洋及东印度洋为主、大西洋为辅的暖海温引起的热带四极型Walker环流异常。此时热带西太平洋到东印度洋局地偏强的经圈Hadley环流可能是SLB异常环流维持的主要原因。
