Abstract Vertical gradients incorporate multiple resources gradients which vary continuously. Therefore, research on mountain floristic patterns along vertical gradients is important to reveal regular patterns of the ...Abstract Vertical gradients incorporate multiple resources gradients which vary continuously. Therefore, research on mountain floristic patterns along vertical gradients is important to reveal regular patterns of the flora along environmental gradients and to under- stand the changes in biodiversity along these gradients and their biological fitness. This study was designed to explore the character- istics of the floral compositions and ecological significance of floristic patterns along the vertical gradients of the National Nature Reserve of Dawei Mountain, located in the southeast of Yunnan Province. We analyzed the structural characteristics of the flora and the distribution patterns of its floristic components as a function of elevation on the basis of our field investigations along vertical vegetation transects. We carried out a systematic cluster analysis in order to determine the dividing line of floristic changes by eleva- tion along gradients and studied the effects of mountain climate on the vertical variation of floristic composition. The study shows： 1） that the obvious boundary, which differentiates tropical distribution, is located at an elevation of approximately 1,500 m, which separates the tropical rain forests from the evergreen broad-leaved forests; 2） that humid rain forests are found below 700 m elevation, mountain rain forests between 700 and 1,500 m, monsoon evergreen broad-leaved forests between 1,300 and 1,800 m and mountain mossy evergreen broad-leaved forests above 1,800 m. Non-representative mountain mossy dwarf forests （above 2,100 m） in the area are found on the windward sides and barren lands on mountain slopes; 3） that Hopea mollissima is one of the major component species of mountain rain forests, but it should not be considered as the major indicator species in humid rain forests as is generally accepted.展开更多
The economic benefits of transport infrastructure investment have been widely accepted.However,the varying influence of road transport development across vertical space has rarely been discussed.Taking Sichuan provinc...The economic benefits of transport infrastructure investment have been widely accepted.However,the varying influence of road transport development across vertical space has rarely been discussed.Taking Sichuan province in China as case study area where the landform is diverse and complex,administrative counties were categorized into 4 main types:plain counties,hill counties,mountain counties,and plateau counties.Using statistical data during 2006-2014,theperformanceofeconomic development and transport construction level in the four types of counties are discussed.Subsequently,the heterogeneous effect of each grade road on economy was calculated by local regression model(GWR).The results indicate that plain counties largely surpassed the other geomorphic counties in economic development level,while the gradient gap among them was on the decline.Similarly,distribution of transport infrastructure presented a decreasing trend from the low plain counties to high plateau counties.Regional imbalances were mainly reflected in the County road and Village road.Regarding the changes of regional gaps,National&Provincial roads and County roads were constantly expanding,whereas the disparity of Village road was slowly narrowing over time.Particularly noteworthy was the non-stationary economic influence of traffic factors across vertical gradients.On average,National&Provincial roads generated higher benefits in the high elevation regions than the lowlands.In contrast,County road and Village road were found to be more effective in promoting economic development in plains.With regard to local estimates of traffic factors,coefficients in mountain counties exhibited larger fluctuation ranges than other geomorphic units.The conclusions provide a basis for government decisionmaking in a more reasonable construction arrangement of road facilities and sustainable economic development.展开更多
文摘Abstract Vertical gradients incorporate multiple resources gradients which vary continuously. Therefore, research on mountain floristic patterns along vertical gradients is important to reveal regular patterns of the flora along environmental gradients and to under- stand the changes in biodiversity along these gradients and their biological fitness. This study was designed to explore the character- istics of the floral compositions and ecological significance of floristic patterns along the vertical gradients of the National Nature Reserve of Dawei Mountain, located in the southeast of Yunnan Province. We analyzed the structural characteristics of the flora and the distribution patterns of its floristic components as a function of elevation on the basis of our field investigations along vertical vegetation transects. We carried out a systematic cluster analysis in order to determine the dividing line of floristic changes by eleva- tion along gradients and studied the effects of mountain climate on the vertical variation of floristic composition. The study shows： 1） that the obvious boundary, which differentiates tropical distribution, is located at an elevation of approximately 1,500 m, which separates the tropical rain forests from the evergreen broad-leaved forests; 2） that humid rain forests are found below 700 m elevation, mountain rain forests between 700 and 1,500 m, monsoon evergreen broad-leaved forests between 1,300 and 1,800 m and mountain mossy evergreen broad-leaved forests above 1,800 m. Non-representative mountain mossy dwarf forests （above 2,100 m） in the area are found on the windward sides and barren lands on mountain slopes; 3） that Hopea mollissima is one of the major component species of mountain rain forests, but it should not be considered as the major indicator species in humid rain forests as is generally accepted.
基金supported by the National Natural Science Foundation of China (Grants No. 41571523 and 41661144038)the National Basic Research Program of China (973 Program) (Grant No. 2013CBA01808)the National Key Technology Research and Development Program of the Ministry of Science and Technology of China (Grant No. 2014BAC05B01)
文摘The economic benefits of transport infrastructure investment have been widely accepted.However,the varying influence of road transport development across vertical space has rarely been discussed.Taking Sichuan province in China as case study area where the landform is diverse and complex,administrative counties were categorized into 4 main types:plain counties,hill counties,mountain counties,and plateau counties.Using statistical data during 2006-2014,theperformanceofeconomic development and transport construction level in the four types of counties are discussed.Subsequently,the heterogeneous effect of each grade road on economy was calculated by local regression model(GWR).The results indicate that plain counties largely surpassed the other geomorphic counties in economic development level,while the gradient gap among them was on the decline.Similarly,distribution of transport infrastructure presented a decreasing trend from the low plain counties to high plateau counties.Regional imbalances were mainly reflected in the County road and Village road.Regarding the changes of regional gaps,National&Provincial roads and County roads were constantly expanding,whereas the disparity of Village road was slowly narrowing over time.Particularly noteworthy was the non-stationary economic influence of traffic factors across vertical gradients.On average,National&Provincial roads generated higher benefits in the high elevation regions than the lowlands.In contrast,County road and Village road were found to be more effective in promoting economic development in plains.With regard to local estimates of traffic factors,coefficients in mountain counties exhibited larger fluctuation ranges than other geomorphic units.The conclusions provide a basis for government decisionmaking in a more reasonable construction arrangement of road facilities and sustainable economic development.
