Sixteen different vegetation types of grassland and shrubland were selected to study the component and diversity of plant species of riparian plant communities along main channel in the Three-Gorges areas. Species ric...Sixteen different vegetation types of grassland and shrubland were selected to study the component and diversity of plant species of riparian plant communities along main channel in the Three-Gorges areas. Species richness (s), Simpson index (D), and Shannon-Weiner index (H) were used to study the biodiversity and the hierarchical classification was carried out by the methods of TWINSPAN and DCA ordination. The results showed that the components of flora were complex and dominated by the temperate type in the riparian plant communities. Species diversity was not different between the communities, but Shannon-Weiner indexes of different layers in some grassland were significantly different. TWINSPAN and DCA indicated that riparian plant communities distributed along the gradient of moisture.展开更多
In this paper,the quantitative approach is applied on the study of coniferous forestbased on the data which were collected by the field investigation in Daxinganling region.The mainpurpose is objectively to show the p...In this paper,the quantitative approach is applied on the study of coniferous forestbased on the data which were collected by the field investigation in Daxinganling region.The mainpurpose is objectively to show the position of communities in the space and the relationship be-tween the community and environment.By means of ordination,it is found that dahurian larch for-est,mongolian scots pine forest and korean fir forest lie in different positions. Gradient analysis ofthree dominant types of conigerous forest has revealed the difference of ecological amplitude,thedifference is one of the important reasons that determine the different communities in the differentenvironment.展开更多
There are really piles of tasks before the Asia-Pacific as the region is approach-ing the 21st century. The course of development of some of the major trendsand contradictions can be foreseen. But the complexity of th...There are really piles of tasks before the Asia-Pacific as the region is approach-ing the 21st century. The course of development of some of the major trendsand contradictions can be foreseen. But the complexity of the situation caused bymulti-laterality and the interdependence and interaction of the countries of the re-gion requires that we should break through the old framework of thinking,展开更多
Objective： Explore laparoscopic cholecystectomy ordination and nursing methods. Methods： A retrospective analysis of our hospital from July 2009 to January 2011 Laparoscopic cholecystectomy in 89 cases of nursing da...Objective： Explore laparoscopic cholecystectomy ordination and nursing methods. Methods： A retrospective analysis of our hospital from July 2009 to January 2011 Laparoscopic cholecystectomy in 89 cases of nursing data. Results： This group of patients the operation is successful, no serious complications occurred. Through surgery and nursing, has obtained the desired effect .Conclusions： The accuracy of the nursing co-ordination is to ensure the success of laparoscopic cholecystectomy. The most important thing is, with laparoscopic cholecystectomy and intraoperative nursing can improve the quality of life of patients.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
Aims Forest vegetation variability may be explained by the complex inter-play among several spatial structuring factors,including climate and topography.We modelled the spatial variability of forest vegetation assembl...Aims Forest vegetation variability may be explained by the complex inter-play among several spatial structuring factors,including climate and topography.We modelled the spatial variability of forest vegetation assemblages and significant environmental variables along a com-plex environmental gradient or coenocline to produce a detailed cartographic database portraying the distribution of forests along it.Methods We combined an analysis of ordination coenoclines with kriging over 772 field data plots from the third Spanish National Forest Inventory in an Atlantic-Mediterranean transitional area(northern Spain).Important Findings The best fitted empirical semivariogram revealed a strong spatial structure of forest species composition along the complex envi-ronmental gradient considered(the climatic-topographic gradient from north to south).The steady and gradual increase of semivari-ance with a marked lag distance indicates a gradual turnover of forest assemblages according to the climatic-topographic vari-ations(regional or local).Two changes in the slope of the semi-variogram suggest the existence of two different scales of spatial variation.The interpolation map by Kriging of forest vegetation assemblages along the main coenocline shows a clear spatial dis-tribution pattern of trees and shrubs in accordance with the spa-tial variation of significant environmental variables.We concluded that the multivariate geostatistical approach is a suitable technique for spatial analysis of forest systems employing data from national forest inventories based on a regular network of field plots.The development of an assortment of maps describing changes in veg-etation assemblages and variation in environmental variables is expected to be a suitable tool for an integrated forest management and planning.展开更多
This study aimed to screen out cold-tolerant sugarcane cultivars through acomprehensive cold tolerance evaluation. A total of 9 sugarcane cultivars with good agronomic traits, bred by the Yunnan Agricultural Universit...This study aimed to screen out cold-tolerant sugarcane cultivars through acomprehensive cold tolerance evaluation. A total of 9 sugarcane cultivars with good agronomic traits, bred by the Yunnan Agricultural University, were selected. They were treated by low temperaturestress （3 ℃）, and the changes of their cold-tolerant physiological and biochemical indices were monitored. The cold tolerance of the sugarcane cultivars was evaluated comprehensively by polar ordination. The results showed that the low temperature stress increased the averagemembrane conductivi- ty, soluble sugar content, MDA content, proline content, soluble protein content, chlorophyll content and peroxidase （POD） activity in sugarcane leaves by 21.21%, 134.1%, 83.60%, 35.47%, 47.72%, 9.07% and 565.2%, respectively, but decreased the superoxide dismutase （SOD） activity in sugarcane leaves by 19.67%. Among the 9 sugarcane cultivars, Dianzhe 03-91 showed the strongest cold tolerance, while Dianzhe 02-39 showed the poorest cold tolerance; the cold tolerance of Dianzhe 08-5, Dianzhe 05-103 and Dianzhe 01-58 was stronger than that of Dianzhe 04- 14, Dianzhe 04-429, Dianzhe 05-522 and Dianzhe 02-227.展开更多
We investigated the composition of plant communities to quantify their relationships with environmental parameters in the Chitral Hindukush range of Pakistan. We sampled tree vegetation using the Point Centered Quart...We investigated the composition of plant communities to quantify their relationships with environmental parameters in the Chitral Hindukush range of Pakistan. We sampled tree vegetation using the Point Centered Quarter （PCQ） method while understory vegetation was sampled in 1.5-m circular quadrats. Cedrus deodara is the national symbol of Pakistan and was dominant in the sampled communities. Because environmental variables determine vegetation types, we analyzed and evaluated edaphic and topographic factors. DCA-Ordination showed the major gradient as an amalgam of elevation （p〈0.05） and slope （p〈0.01） as the topographic factors correlated with species distribution. Soil variables were the factors of environmental significance along DCA axes. However, among these factors, Mg2＋ , K ＋ and N2＋ contributed not more than 0.054% 0.20% and 0.073%, respectively, to variation along the first ordination axis. We conclude that the principal reason for weak or no correlation with many edaphic variables was the anthropogenic disturbance of vegetation. The understory vegetation was composed of perennial herbs in most communities and was most dense under the tree canopy. The understory vegetation strongly regulates tree seedling growth and regeneration patterns. We recommend further study of the understory vegetation using permanent plots to aid development of forest regeneration strategies.展开更多
Environmental heterogeneity significantly affects the structure of ecological communities.Exploring vegetation distribution and its relationship with environmental factors is essential to understanding the abiotic mec...Environmental heterogeneity significantly affects the structure of ecological communities.Exploring vegetation distribution and its relationship with environmental factors is essential to understanding the abiotic mechanism(s)driving vegetation succession,especially in the ecologically fragile areas.In this study,based on the quantitative analysis of plant community and environmental factors in 68 plots at 10 different transects in the Minqin oasis-desert ecotone(ODE)of northwestern China,we investigated desert vegetation distribution and species-environment relationships using multivariate analysis.Two-way indicator species analysis(TWINSPAN),detrended correspondence analysis(DCA),and canonical correspondence analysis(CCA)methods were used.A total of 28 species,belonging to 27 genera in 8 families,were identified.Chenopodiaceae,Zygophyllaceae,Gramineae,and Leguminosae were the largest families.Annual and perennial herbs accounted for 28.60%of the total number of plants,while shrubs(42.90%)were the most dominant.Nitraria tangutorum was the constructive species of the desert plant community.We divided the 68 plots surveyed in this study into 7 community types,according to the results of TWINSPAN.The distribution of these 7 communities in the DCA ordination graph showed that species with a similar ecotype were clustered together.Results of CCA indicated that groundwater was the dominant factor influencing vegetation distribution,while distance between plot and oasis(Dis)and soil electrical conductivity(EC)were the local second-order factors.Our study suggests that optimizing the utilization of groundwater in oases is key to controlling the degradation of desert vegetation.The favorable topographic conditions of sand dunes should be fully utilized for vegetal dune stabilization,and the influence of soil salinity on the selection of afforestation tree species should be considered.展开更多
A considerable proportion of Iran＇s territory is covered with arid and semi-arid rangelands and mismanagement and overexploitation of those rangelands have resulted in serious ecological degradation. Thus, the need i...A considerable proportion of Iran＇s territory is covered with arid and semi-arid rangelands and mismanagement and overexploitation of those rangelands have resulted in serious ecological degradation. Thus, the need is pressing to examine the present species composition and the relationships with environmental factors for providing the needed scientific references to species conservation and ecological rehabilitation efforts. The aims of this study were to examine the species composition and to delineate the most important factors influencing the distributions of plant species and groups in the northern rangelands of Isfahan Province （Iran） using two-way indicator species analysis （TWINSPAN）, detrended correspondence analysis （DCA）, principal component analysis （PCA）, and canonical correspondence analysis （CCA）. Field investigations were conducted in the growing season of 2014 using stratified random method in 22 homogeneous sampling units. In total, 75 plant species belonging to 52 genera and 19 families were identified. The most important families were Asteraceae and Papilionaceae, the most important genera were Astragalus, Cousinia, and Acanthophyllum, and the most important species were Artemisia aucheri and Artemisia sieberi. Plant species were classified into 10 groups using TWINSPAN. DCA was used to estimate the magnitude of changes in species composition along the first two ordination axes to provide gradient length estimations for PCA and CCA ordinations. The first three PCA axes and the first three CCA axes demonstrated similar cumulative percentage of variance, indicating that the environmental factors （selected by PCA） used in CCA ordination were acceptable for explaining the species composition and the distributions. CCA ordination showed that the first axis was closely related to elevation, slope, surface bare soil cover, surface litter cover, gravel proportion, organic matter, total nitrogen, CaCO3 content, and grazing intensity and that the second axis was closely related to sand proportion, silt proportion, clay proportion, and saturation percentage. Among these factors, elevation was the most effective factor to separate the plant groups and grazing was the major cause of rangeland degradation.展开更多
基金This study was supported by the Chinese Academy of Sciences (A grant KZCX2-406) the National Natural Science Foundation of China (NSFC39970123) and Changbai Mountain Open Research Station.
文摘Sixteen different vegetation types of grassland and shrubland were selected to study the component and diversity of plant species of riparian plant communities along main channel in the Three-Gorges areas. Species richness (s), Simpson index (D), and Shannon-Weiner index (H) were used to study the biodiversity and the hierarchical classification was carried out by the methods of TWINSPAN and DCA ordination. The results showed that the components of flora were complex and dominated by the temperate type in the riparian plant communities. Species diversity was not different between the communities, but Shannon-Weiner indexes of different layers in some grassland were significantly different. TWINSPAN and DCA indicated that riparian plant communities distributed along the gradient of moisture.
文摘In this paper,the quantitative approach is applied on the study of coniferous forestbased on the data which were collected by the field investigation in Daxinganling region.The mainpurpose is objectively to show the position of communities in the space and the relationship be-tween the community and environment.By means of ordination,it is found that dahurian larch for-est,mongolian scots pine forest and korean fir forest lie in different positions. Gradient analysis ofthree dominant types of conigerous forest has revealed the difference of ecological amplitude,thedifference is one of the important reasons that determine the different communities in the differentenvironment.
文摘There are really piles of tasks before the Asia-Pacific as the region is approach-ing the 21st century. The course of development of some of the major trendsand contradictions can be foreseen. But the complexity of the situation caused bymulti-laterality and the interdependence and interaction of the countries of the re-gion requires that we should break through the old framework of thinking,
文摘Objective： Explore laparoscopic cholecystectomy ordination and nursing methods. Methods： A retrospective analysis of our hospital from July 2009 to January 2011 Laparoscopic cholecystectomy in 89 cases of nursing data. Results： This group of patients the operation is successful, no serious complications occurred. Through surgery and nursing, has obtained the desired effect .Conclusions： The accuracy of the nursing co-ordination is to ensure the success of laparoscopic cholecystectomy. The most important thing is, with laparoscopic cholecystectomy and intraoperative nursing can improve the quality of life of patients.
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).
基金J.G.A.was supported by the program‘Juan de la Cierva-Incorporación’fellowships(IJCI-2014-21393).
文摘Aims Forest vegetation variability may be explained by the complex inter-play among several spatial structuring factors,including climate and topography.We modelled the spatial variability of forest vegetation assemblages and significant environmental variables along a com-plex environmental gradient or coenocline to produce a detailed cartographic database portraying the distribution of forests along it.Methods We combined an analysis of ordination coenoclines with kriging over 772 field data plots from the third Spanish National Forest Inventory in an Atlantic-Mediterranean transitional area(northern Spain).Important Findings The best fitted empirical semivariogram revealed a strong spatial structure of forest species composition along the complex envi-ronmental gradient considered(the climatic-topographic gradient from north to south).The steady and gradual increase of semivari-ance with a marked lag distance indicates a gradual turnover of forest assemblages according to the climatic-topographic vari-ations(regional or local).Two changes in the slope of the semi-variogram suggest the existence of two different scales of spatial variation.The interpolation map by Kriging of forest vegetation assemblages along the main coenocline shows a clear spatial dis-tribution pattern of trees and shrubs in accordance with the spa-tial variation of significant environmental variables.We concluded that the multivariate geostatistical approach is a suitable technique for spatial analysis of forest systems employing data from national forest inventories based on a regular network of field plots.The development of an assortment of maps describing changes in veg-etation assemblages and variation in environmental variables is expected to be a suitable tool for an integrated forest management and planning.
基金Supported by National Natural Science Foundation of China(31560417)Applied Basic Research Program of Science and Technology Commission Foundation of Yunnan Province(2015FA024)+2 种基金Program for Industry Technology System of Cane in Yunnan(YCJ[2015]90)Key New Product Development Plan of Yunnan Province(2012BB014)Program for Innovation Research Team in Yunnan Province(YKRF[2012]18)~~
文摘This study aimed to screen out cold-tolerant sugarcane cultivars through acomprehensive cold tolerance evaluation. A total of 9 sugarcane cultivars with good agronomic traits, bred by the Yunnan Agricultural University, were selected. They were treated by low temperaturestress （3 ℃）, and the changes of their cold-tolerant physiological and biochemical indices were monitored. The cold tolerance of the sugarcane cultivars was evaluated comprehensively by polar ordination. The results showed that the low temperature stress increased the averagemembrane conductivi- ty, soluble sugar content, MDA content, proline content, soluble protein content, chlorophyll content and peroxidase （POD） activity in sugarcane leaves by 21.21%, 134.1%, 83.60%, 35.47%, 47.72%, 9.07% and 565.2%, respectively, but decreased the superoxide dismutase （SOD） activity in sugarcane leaves by 19.67%. Among the 9 sugarcane cultivars, Dianzhe 03-91 showed the strongest cold tolerance, while Dianzhe 02-39 showed the poorest cold tolerance; the cold tolerance of Dianzhe 08-5, Dianzhe 05-103 and Dianzhe 01-58 was stronger than that of Dianzhe 04- 14, Dianzhe 04-429, Dianzhe 05-522 and Dianzhe 02-227.
基金supported by the Higher Education Commission of Pakistan
文摘We investigated the composition of plant communities to quantify their relationships with environmental parameters in the Chitral Hindukush range of Pakistan. We sampled tree vegetation using the Point Centered Quarter （PCQ） method while understory vegetation was sampled in 1.5-m circular quadrats. Cedrus deodara is the national symbol of Pakistan and was dominant in the sampled communities. Because environmental variables determine vegetation types, we analyzed and evaluated edaphic and topographic factors. DCA-Ordination showed the major gradient as an amalgam of elevation （p〈0.05） and slope （p〈0.01） as the topographic factors correlated with species distribution. Soil variables were the factors of environmental significance along DCA axes. However, among these factors, Mg2＋ , K ＋ and N2＋ contributed not more than 0.054% 0.20% and 0.073%, respectively, to variation along the first ordination axis. We conclude that the principal reason for weak or no correlation with many edaphic variables was the anthropogenic disturbance of vegetation. The understory vegetation was composed of perennial herbs in most communities and was most dense under the tree canopy. The understory vegetation strongly regulates tree seedling growth and regeneration patterns. We recommend further study of the understory vegetation using permanent plots to aid development of forest regeneration strategies.
基金supported by the National Key Research and Development Program of China(SQ2016YFHZ20617-03,2018YFC0507102-05)the National Natural Science Foundation of China(41661008,41761051,41761006,41661064,31560128,41801102)
文摘Environmental heterogeneity significantly affects the structure of ecological communities.Exploring vegetation distribution and its relationship with environmental factors is essential to understanding the abiotic mechanism(s)driving vegetation succession,especially in the ecologically fragile areas.In this study,based on the quantitative analysis of plant community and environmental factors in 68 plots at 10 different transects in the Minqin oasis-desert ecotone(ODE)of northwestern China,we investigated desert vegetation distribution and species-environment relationships using multivariate analysis.Two-way indicator species analysis(TWINSPAN),detrended correspondence analysis(DCA),and canonical correspondence analysis(CCA)methods were used.A total of 28 species,belonging to 27 genera in 8 families,were identified.Chenopodiaceae,Zygophyllaceae,Gramineae,and Leguminosae were the largest families.Annual and perennial herbs accounted for 28.60%of the total number of plants,while shrubs(42.90%)were the most dominant.Nitraria tangutorum was the constructive species of the desert plant community.We divided the 68 plots surveyed in this study into 7 community types,according to the results of TWINSPAN.The distribution of these 7 communities in the DCA ordination graph showed that species with a similar ecotype were clustered together.Results of CCA indicated that groundwater was the dominant factor influencing vegetation distribution,while distance between plot and oasis(Dis)and soil electrical conductivity(EC)were the local second-order factors.Our study suggests that optimizing the utilization of groundwater in oases is key to controlling the degradation of desert vegetation.The favorable topographic conditions of sand dunes should be fully utilized for vegetal dune stabilization,and the influence of soil salinity on the selection of afforestation tree species should be considered.
文摘A considerable proportion of Iran＇s territory is covered with arid and semi-arid rangelands and mismanagement and overexploitation of those rangelands have resulted in serious ecological degradation. Thus, the need is pressing to examine the present species composition and the relationships with environmental factors for providing the needed scientific references to species conservation and ecological rehabilitation efforts. The aims of this study were to examine the species composition and to delineate the most important factors influencing the distributions of plant species and groups in the northern rangelands of Isfahan Province （Iran） using two-way indicator species analysis （TWINSPAN）, detrended correspondence analysis （DCA）, principal component analysis （PCA）, and canonical correspondence analysis （CCA）. Field investigations were conducted in the growing season of 2014 using stratified random method in 22 homogeneous sampling units. In total, 75 plant species belonging to 52 genera and 19 families were identified. The most important families were Asteraceae and Papilionaceae, the most important genera were Astragalus, Cousinia, and Acanthophyllum, and the most important species were Artemisia aucheri and Artemisia sieberi. Plant species were classified into 10 groups using TWINSPAN. DCA was used to estimate the magnitude of changes in species composition along the first two ordination axes to provide gradient length estimations for PCA and CCA ordinations. The first three PCA axes and the first three CCA axes demonstrated similar cumulative percentage of variance, indicating that the environmental factors （selected by PCA） used in CCA ordination were acceptable for explaining the species composition and the distributions. CCA ordination showed that the first axis was closely related to elevation, slope, surface bare soil cover, surface litter cover, gravel proportion, organic matter, total nitrogen, CaCO3 content, and grazing intensity and that the second axis was closely related to sand proportion, silt proportion, clay proportion, and saturation percentage. Among these factors, elevation was the most effective factor to separate the plant groups and grazing was the major cause of rangeland degradation.
