The serious degradation of the ecological environment and the rapid expansion of stone desert have had a serious effect on the economic development of karst and rock-naked mountain areas in Southwest China. Moreover, ...The serious degradation of the ecological environment and the rapid expansion of stone desert have had a serious effect on the economic development of karst and rock-naked mountain areas in Southwest China. Moreover, these areas are still at the initial stage of industrialization, characterized by a greater significance of agriculture to the economy, face sharp contradictions among the population, the arable land and resources, and are suffering because of a shortage of investment. On the basis of this current situation, three recommendations are made in this article: "coordinating the relations among grain, ecology, population and economic development", "increasing the input of science and technology", and "adopting policies consistent with social equity in areas of poverty".展开更多
Located in the western hinterland,Southwest China is a typical mountainous area covered by plateaus,mountains and hills.Its ruggedness hinders regional internal and external connections,and its poor transportation inf...Located in the western hinterland,Southwest China is a typical mountainous area covered by plateaus,mountains and hills.Its ruggedness hinders regional internal and external connections,and its poor transportation infrastructure has long constrained the socioeconomic development of Southwest China.Based on the GIS transportation database,this paper explored the spatiotemporal evolution and characteristics of the land transportation networks and the accessibility of Southwest China from 1917 to 2017.Regional accessibility in Southwest China has significantly improved,and transportation infrastructure has gradually integrated the transportation circles of the52 central cities.The transportation network has followed an evolutionary process from a"hub-spoke pattern"to a"network pattern",while the construction of a high-speed railway(HSR)has brought about significant spatial polarization.We argue that innovation in transportation technology is one of the most effective factors for promoting a significant change in regional accessibility.In addition,the spatial distribution and evolution of accessibility in Southwest China presents a verticalcharacteristic that distinguishes it from the plains,as the spillover effects of new transportation infrastructure on accessibility improvement are partly offset by the mountainous terrain.Additionally,in Southwest China,there is significant"path dependence"in the evolution of the transportation network,since a large portion of the population is concentrated along transportation corridors in mountainous areas.展开更多
The chemical composition of rainwater has been studied in a karst rural area from September 2012 to August 2013 in Guizhou Province,Southwest China.The results indicated that the VWM value of p H was 5.4,varied from 4...The chemical composition of rainwater has been studied in a karst rural area from September 2012 to August 2013 in Guizhou Province,Southwest China.The results indicated that the VWM value of p H was 5.4,varied from 4.6 to 6.9.Ca^(2+)and NH_4^+were the major cations,and SO_4^(2-)was the dominant anion.Neutralization factors show that the acid was mainly neutralized by Ca^(2+),NH_4^+and Mg^(2+).Investigations of correlation coefficients and enrichment factors revealed that Ca^(2+)and Mg^(2+)were mainly crust origins,and NH_4^+was from agriculture and livestock manure.SO_4^(2-)and NO_3^-were mainly from anthropogenic sources.展开更多
Characteristics and distributions of humic acid(HA) and soil organic matter(SOM) in a yellow soil profile and a limestone soil profile of the southwest China Karst area were systematically investigated to reveal their...Characteristics and distributions of humic acid(HA) and soil organic matter(SOM) in a yellow soil profile and a limestone soil profile of the southwest China Karst area were systematically investigated to reveal their evolutions in different soils of the study area. The results showed that characteristics and distribution of SOM along the two soil profiles were notably different. Total organic carbon(TOC) contents of soil samples decreased just slightly along the limestone soil profile but sharply along the yellow soil profile. TOCs of the limestone soils were significantly higher than those of the corresponding yellow soils, and C/N ratios of SOMs showed a similar variation trend to that of TOCs, indicating that SOM can be better conserved in the limestone soil than in the yellow soil. The soil humic acids were exhaustively extracted and further fractionated according to their apparent molecular weights using ultrafiltration techniques to explore underlying conservation mechanisms. The result showed that C/N ratios of HAs from different limestone soil layers were relatively stable and that large molecular HA fractions predominated the bulk HA of the top soil, indicating that HA in the limestone profile was protected while bio and chemical degradations were retarded. Combined with organic elements contents and mineral contents of two soils, weconcluded that high calcium contents in limestone soils may play a key role in SOM conservation by forming complexation compounds with HAs or/and enclosing SOMs with hypergene CaCO_3 precipitation.展开更多
The aim was to further research soil erosion characteristics and accurately predict soil erosion amount in karst areas. Based on field surveys and research achievements available, yellow soils, which are widely distri...The aim was to further research soil erosion characteristics and accurately predict soil erosion amount in karst areas. Based on field surveys and research achievements available, yellow soils, which are widely distributed, were chosen as test soil samples and slope, rain intensity, vegetation coverage and bare-rock ratio were taken as soil erosion factors. Artificial rain simulation instruments (needle-type) were made use of to simulate correlation of rain intensity, vegetation coverage, and bare-rock ratio with soil erosion quantity. Furthermore, multiple-factor linear regression analysis, stepwise regression analysis and multiple-factor non-linear regression analy- sis were made to establish a multiple-factor formula of soil erosion modulus with dif- ferent slopes and select regression models with high correlation coefficients. The re- sults show that a non-linear regression model reached extremely significant level or significant level (0.692〈FF〈0.988) and linear regression model achieved significant lev- el (0.523〈FF〈0.634). The effects of erosion modulus changed from decreasing to in- creasing and the erosion factors from high to low were rain intensity, vegetation cov- erage and bare-rock ratio when slope gradient was at 6~, 16~, 26~ and 36~. The mod- el is of high accuracy for predicting gentle slope and abtupt slope, which reveals correlation of erosion modulus with erosion factors in karst areas.展开更多
The Karst of Southwest China is a typical representative of poverty stricken region with impoverishment-degradation spiral. To essentially break away from this vicious circle, the local ecology, economy and society s...The Karst of Southwest China is a typical representative of poverty stricken region with impoverishment-degradation spiral. To essentially break away from this vicious circle, the local ecology, economy and society should be rehabilitated, and hence to strengthen the self-development capacity building of the localities. Two considerations are stressed in this article: (1) Poverty alleviation is a system project with great complexities. Any single approach is difficult to success and integrated measures should be taken. (2) Some typical and feasible areas should be selected to demonstrate the project of poverty alleviation and ecological, socio-economic reconstruction. Then, they can be used as a model to promote the sustainable development of the whole region. Based upon these ideals, a project entitled “Reversal of Impoverishment-Degradation Spiral in the Karst of Southwest China' was proposed and has been listed in 《Priority Programme for China's Agenda 21》.展开更多
Based on the survey data of 150 peasant households in typical Karst mountainous area in the year 2009, causations, characteristics and influence factors of the concurrent-business behavior of peasant households during...Based on the survey data of 150 peasant households in typical Karst mountainous area in the year 2009, causations, characteristics and influence factors of the concurrent-business behavior of peasant households during planting structure adjustment are analyzed. Result shows that there is significant positive correlation between the concurrent-business income and the household income of farmers. And the concurrent-business behavior has the tendency to be popular among the young farmers with the characteristics of relative concentration, strong will of farmers and the significant impact of education degree on the concurrent-business income. Information, capital, skill, and market awareness are the main factors affecting the concurrent-business behavior of peasant households. Countermeasures to optimize the concurrent-business behavior of peasant households are put forward, such as strengthening the skills training for farmers to improve the cultural quality of peasant households, establishing modern rural financial service system to offer capital support for the development of peasant households, setting up information base of rural labor force to provide more information and channels for the concurrent-business behavior of peasant households, and enhancing the cultivation of farmers' market awareness to improve their ability to adapt to market economy.展开更多
This paper focuses on migration occurrence as a result of environmental degradation and population growth. It briefly reviews previous practices in some less developed courtries and then considers the extent to which ...This paper focuses on migration occurrence as a result of environmental degradation and population growth. It briefly reviews previous practices in some less developed courtries and then considers the extent to which environmental factors have been and may be significant in initiating migration. A case study of the karst region of southwest China is used to illustrate the phenomenon, including root causes, restrictive factors, nature of the migration, desires of migrants, strategies of response and optional policies. It is argued that a comprehensive approach to the prevention of environmentally caused displacement should be developed.展开更多
Emergency road networks(ERNs),an important part of local disaster prevention systems,can provide security to residents and their property.Exploring the ERNs structure is of great significance in terms of promoting dis...Emergency road networks(ERNs),an important part of local disaster prevention systems,can provide security to residents and their property.Exploring the ERNs structure is of great significance in terms of promoting disaster prevention and establishing road safety in dangerous mountainous areas.This study considered the ERNs of the Kangding section of the Dadu River Basin as the area for a case study.Complex Network Analysis was used to examine the relationship between the four characteristic indicators of mountain roads and the degree of earthquake impacts under the Lushan,Wenchuan,and Kangding Earthquake scenarios.Based on the analysis results,the southwest mountain road network was evaluated;then,computer simulations were used to evaluate the structural changes in the road network after index changes.The network was optimized,and the corresponding emergency avoidance network was proposed to provide a reference for the establishment of the mountainous ERN.The results show that the overall completeness of the mountainous ERNs in Southwest China is poor and prone to traffic accidents.Moreover,the local stability is poor,and the network is susceptible to natural hazards.The overall structure of the road network is balanced,but that of certain road sections is not.Road sections with different attributes present a“gathering-scattering”spatial distribution,i.e,some sections are clustered together while others are far apart.Accordingly,a planning optimization strategy is proposed to better understand the complexity and systematic nature of the mountainous ERN as a whole and to provide a reference for disaster prevention and mitigation planning in mountainous regions in Southwest China.展开更多
In mountainous areas, it is the undulant terrain, various types of geomorphic and land use that make the remote sensing images great metamorphism. Moreover, due to the elevation, there are many areas covered with shad...In mountainous areas, it is the undulant terrain, various types of geomorphic and land use that make the remote sensing images great metamorphism. Moreover, due to the elevation, there are many areas covered with shadow, clouds and snow that make the images more inaccurate. As a result, it would be very difficult to carry out auto-classification of RS images in these areas. The study took Southwest China as the case study area and the TM images, SPOT images as the basic information sources assisted by the auxiliary data of DEM, NDVl, topographical maps and soil maps to preprocess the images. After preprocessing by topographic correction and wiping off clouds, snow and shadows, all the image data were stacked together to form the images to be classified. Then, the research used segmentation technology and hierarchical method to extract the main types of land use in the area automatically. The results indicated that the qualitative accuracies of all types of land use extracted in Southwest China were above 90 percent, and the quantitative accuracies was above 86 percent. The goal of reducing workloads had been realized.展开更多
人类活动影响喀斯特山区生态系统服务功能。喀斯特山区生态系统服务权衡/协同作用及时空差异特征分析,是指导山区生态恢复及保护的重要依据。当前针对中国喀斯特山区的相关研究多以生态系统服务权衡/协同关系的时间变化为主,较少对权衡...人类活动影响喀斯特山区生态系统服务功能。喀斯特山区生态系统服务权衡/协同作用及时空差异特征分析,是指导山区生态恢复及保护的重要依据。当前针对中国喀斯特山区的相关研究多以生态系统服务权衡/协同关系的时间变化为主,较少对权衡/协同关系变化的空间异质性及空间可视化进行研究,难以全面揭示各类服务间的复杂关系。本研究以云南喀斯特山区广南县为例,采用模型评估及相关分析等方法对六种生态系统服务进行评估,分析其时空变化、空间异质性和权衡/协同变化关系。结果表明:(1)2000—2018年,年均食物供给量和文化价值量呈逐年增加趋势,年均产水量、土壤保持量和固碳价值量呈先减少后增加趋势,年均生境质量呈逐年下降趋势。(2)空间上,食物供给量、文化价值量和产水量呈中部和中南部增加较多的特征,而土壤保持量与其呈大致相反的趋势,固碳价值量和生境质量空间上呈东部增加较多的趋势。(3)自相关关系上,各生态系统服务全局Moran s I指数大小为:固碳>食物供给>土壤保持>产水>文化>生境支持服务,生境支持服务在空间上呈离散化状态,而其他服务均呈集聚分布特征,且空间分异以不显著区和低-低区集群分布为主。(4)权衡/协同关系的时间变化格局上,生境支持服务-固碳释氧相关性为高度正相关,协同性系数最高,而产水-土壤保持相关性为中度负相关,权衡性系数最低;空间变化格局上,食物供给-产水、文化-固碳间空间分布均为协同关系,产水-土壤保持、固碳-产水均为权衡关系。空间格局整体以协同关系为主,权衡区与协同区空间分布有所差异。生态系统服务相关性及权衡/协同分析,有助于对研究区自然资源进行宏观调控,缓解经济发展与生态保护的矛盾。研究结果丰富了喀斯特山区生态系统恢复这一领域研究内容,有利于促进广南县资源环境的协调发展。展开更多
文摘The serious degradation of the ecological environment and the rapid expansion of stone desert have had a serious effect on the economic development of karst and rock-naked mountain areas in Southwest China. Moreover, these areas are still at the initial stage of industrialization, characterized by a greater significance of agriculture to the economy, face sharp contradictions among the population, the arable land and resources, and are suffering because of a shortage of investment. On the basis of this current situation, three recommendations are made in this article: "coordinating the relations among grain, ecology, population and economic development", "increasing the input of science and technology", and "adopting policies consistent with social equity in areas of poverty".
基金supported by the National Natural Science Foundation of China(Grants No.41671159)Fundamental Research Funds for the Central Universities for funding(Grants No.XDJK2018B011)Major Projects on Philosophy and Social Sciences of Chongqing Education Commission(Grants No.19SKZDZX08)。
文摘Located in the western hinterland,Southwest China is a typical mountainous area covered by plateaus,mountains and hills.Its ruggedness hinders regional internal and external connections,and its poor transportation infrastructure has long constrained the socioeconomic development of Southwest China.Based on the GIS transportation database,this paper explored the spatiotemporal evolution and characteristics of the land transportation networks and the accessibility of Southwest China from 1917 to 2017.Regional accessibility in Southwest China has significantly improved,and transportation infrastructure has gradually integrated the transportation circles of the52 central cities.The transportation network has followed an evolutionary process from a"hub-spoke pattern"to a"network pattern",while the construction of a high-speed railway(HSR)has brought about significant spatial polarization.We argue that innovation in transportation technology is one of the most effective factors for promoting a significant change in regional accessibility.In addition,the spatial distribution and evolution of accessibility in Southwest China presents a verticalcharacteristic that distinguishes it from the plains,as the spillover effects of new transportation infrastructure on accessibility improvement are partly offset by the mountainous terrain.Additionally,in Southwest China,there is significant"path dependence"in the evolution of the transportation network,since a large portion of the population is concentrated along transportation corridors in mountainous areas.
基金supported by the National Natural Science Foundation of China(Grant Nos.4132501041661144029)National Key Basic Research Program of China(Grant No.2013CB956703)
文摘The chemical composition of rainwater has been studied in a karst rural area from September 2012 to August 2013 in Guizhou Province,Southwest China.The results indicated that the VWM value of p H was 5.4,varied from 4.6 to 6.9.Ca^(2+)and NH_4^+were the major cations,and SO_4^(2-)was the dominant anion.Neutralization factors show that the acid was mainly neutralized by Ca^(2+),NH_4^+and Mg^(2+).Investigations of correlation coefficients and enrichment factors revealed that Ca^(2+)and Mg^(2+)were mainly crust origins,and NH_4^+was from agriculture and livestock manure.SO_4^(2-)and NO_3^-were mainly from anthropogenic sources.
基金financial supports are from the National Major Research Program of China (2013CB956702)the Natural Science Foundation of China (41273149, 41173129)+2 种基金the Science Foundation of Guizhou (20113109)the 100-Talent Program of CASthe opening project from the state key laboratory of environmental geochemistry
文摘Characteristics and distributions of humic acid(HA) and soil organic matter(SOM) in a yellow soil profile and a limestone soil profile of the southwest China Karst area were systematically investigated to reveal their evolutions in different soils of the study area. The results showed that characteristics and distribution of SOM along the two soil profiles were notably different. Total organic carbon(TOC) contents of soil samples decreased just slightly along the limestone soil profile but sharply along the yellow soil profile. TOCs of the limestone soils were significantly higher than those of the corresponding yellow soils, and C/N ratios of SOMs showed a similar variation trend to that of TOCs, indicating that SOM can be better conserved in the limestone soil than in the yellow soil. The soil humic acids were exhaustively extracted and further fractionated according to their apparent molecular weights using ultrafiltration techniques to explore underlying conservation mechanisms. The result showed that C/N ratios of HAs from different limestone soil layers were relatively stable and that large molecular HA fractions predominated the bulk HA of the top soil, indicating that HA in the limestone profile was protected while bio and chemical degradations were retarded. Combined with organic elements contents and mineral contents of two soils, weconcluded that high calcium contents in limestone soils may play a key role in SOM conservation by forming complexation compounds with HAs or/and enclosing SOMs with hypergene CaCO_3 precipitation.
基金Supported by National Science and Technology Support Program in Twelfth Five-year Plan(2012BAD05B06)Special Funds for Excellent Young Scientific Talents in Guizhou[(2011)14]~~
文摘The aim was to further research soil erosion characteristics and accurately predict soil erosion amount in karst areas. Based on field surveys and research achievements available, yellow soils, which are widely distributed, were chosen as test soil samples and slope, rain intensity, vegetation coverage and bare-rock ratio were taken as soil erosion factors. Artificial rain simulation instruments (needle-type) were made use of to simulate correlation of rain intensity, vegetation coverage, and bare-rock ratio with soil erosion quantity. Furthermore, multiple-factor linear regression analysis, stepwise regression analysis and multiple-factor non-linear regression analy- sis were made to establish a multiple-factor formula of soil erosion modulus with dif- ferent slopes and select regression models with high correlation coefficients. The re- sults show that a non-linear regression model reached extremely significant level or significant level (0.692〈FF〈0.988) and linear regression model achieved significant lev- el (0.523〈FF〈0.634). The effects of erosion modulus changed from decreasing to in- creasing and the erosion factors from high to low were rain intensity, vegetation cov- erage and bare-rock ratio when slope gradient was at 6~, 16~, 26~ and 36~. The mod- el is of high accuracy for predicting gentle slope and abtupt slope, which reveals correlation of erosion modulus with erosion factors in karst areas.
文摘The Karst of Southwest China is a typical representative of poverty stricken region with impoverishment-degradation spiral. To essentially break away from this vicious circle, the local ecology, economy and society should be rehabilitated, and hence to strengthen the self-development capacity building of the localities. Two considerations are stressed in this article: (1) Poverty alleviation is a system project with great complexities. Any single approach is difficult to success and integrated measures should be taken. (2) Some typical and feasible areas should be selected to demonstrate the project of poverty alleviation and ecological, socio-economic reconstruction. Then, they can be used as a model to promote the sustainable development of the whole region. Based upon these ideals, a project entitled “Reversal of Impoverishment-Degradation Spiral in the Karst of Southwest China' was proposed and has been listed in 《Priority Programme for China's Agenda 21》.
基金Supported by the National Social Science Foundation of China(08XRK004)the Research Base Program of Humanities and Social Sciences of Guizhou Provincial Department of Education (08JD093)
文摘Based on the survey data of 150 peasant households in typical Karst mountainous area in the year 2009, causations, characteristics and influence factors of the concurrent-business behavior of peasant households during planting structure adjustment are analyzed. Result shows that there is significant positive correlation between the concurrent-business income and the household income of farmers. And the concurrent-business behavior has the tendency to be popular among the young farmers with the characteristics of relative concentration, strong will of farmers and the significant impact of education degree on the concurrent-business income. Information, capital, skill, and market awareness are the main factors affecting the concurrent-business behavior of peasant households. Countermeasures to optimize the concurrent-business behavior of peasant households are put forward, such as strengthening the skills training for farmers to improve the cultural quality of peasant households, establishing modern rural financial service system to offer capital support for the development of peasant households, setting up information base of rural labor force to provide more information and channels for the concurrent-business behavior of peasant households, and enhancing the cultivation of farmers' market awareness to improve their ability to adapt to market economy.
文摘This paper focuses on migration occurrence as a result of environmental degradation and population growth. It briefly reviews previous practices in some less developed courtries and then considers the extent to which environmental factors have been and may be significant in initiating migration. A case study of the karst region of southwest China is used to illustrate the phenomenon, including root causes, restrictive factors, nature of the migration, desires of migrants, strategies of response and optional policies. It is argued that a comprehensive approach to the prevention of environmentally caused displacement should be developed.
基金jointly supported by the National Key R&D Program of China(2018YFD1100804)。
文摘Emergency road networks(ERNs),an important part of local disaster prevention systems,can provide security to residents and their property.Exploring the ERNs structure is of great significance in terms of promoting disaster prevention and establishing road safety in dangerous mountainous areas.This study considered the ERNs of the Kangding section of the Dadu River Basin as the area for a case study.Complex Network Analysis was used to examine the relationship between the four characteristic indicators of mountain roads and the degree of earthquake impacts under the Lushan,Wenchuan,and Kangding Earthquake scenarios.Based on the analysis results,the southwest mountain road network was evaluated;then,computer simulations were used to evaluate the structural changes in the road network after index changes.The network was optimized,and the corresponding emergency avoidance network was proposed to provide a reference for the establishment of the mountainous ERN.The results show that the overall completeness of the mountainous ERNs in Southwest China is poor and prone to traffic accidents.Moreover,the local stability is poor,and the network is susceptible to natural hazards.The overall structure of the road network is balanced,but that of certain road sections is not.Road sections with different attributes present a“gathering-scattering”spatial distribution,i.e,some sections are clustered together while others are far apart.Accordingly,a planning optimization strategy is proposed to better understand the complexity and systematic nature of the mountainous ERN as a whole and to provide a reference for disaster prevention and mitigation planning in mountainous regions in Southwest China.
基金Supported by the National Public Welfare Project on Environmental Protection (2007KYYW21)the Program of National Science and Technology research(2006BAC01A01-05)
文摘In mountainous areas, it is the undulant terrain, various types of geomorphic and land use that make the remote sensing images great metamorphism. Moreover, due to the elevation, there are many areas covered with shadow, clouds and snow that make the images more inaccurate. As a result, it would be very difficult to carry out auto-classification of RS images in these areas. The study took Southwest China as the case study area and the TM images, SPOT images as the basic information sources assisted by the auxiliary data of DEM, NDVl, topographical maps and soil maps to preprocess the images. After preprocessing by topographic correction and wiping off clouds, snow and shadows, all the image data were stacked together to form the images to be classified. Then, the research used segmentation technology and hierarchical method to extract the main types of land use in the area automatically. The results indicated that the qualitative accuracies of all types of land use extracted in Southwest China were above 90 percent, and the quantitative accuracies was above 86 percent. The goal of reducing workloads had been realized.
文摘人类活动影响喀斯特山区生态系统服务功能。喀斯特山区生态系统服务权衡/协同作用及时空差异特征分析,是指导山区生态恢复及保护的重要依据。当前针对中国喀斯特山区的相关研究多以生态系统服务权衡/协同关系的时间变化为主,较少对权衡/协同关系变化的空间异质性及空间可视化进行研究,难以全面揭示各类服务间的复杂关系。本研究以云南喀斯特山区广南县为例,采用模型评估及相关分析等方法对六种生态系统服务进行评估,分析其时空变化、空间异质性和权衡/协同变化关系。结果表明:(1)2000—2018年,年均食物供给量和文化价值量呈逐年增加趋势,年均产水量、土壤保持量和固碳价值量呈先减少后增加趋势,年均生境质量呈逐年下降趋势。(2)空间上,食物供给量、文化价值量和产水量呈中部和中南部增加较多的特征,而土壤保持量与其呈大致相反的趋势,固碳价值量和生境质量空间上呈东部增加较多的趋势。(3)自相关关系上,各生态系统服务全局Moran s I指数大小为:固碳>食物供给>土壤保持>产水>文化>生境支持服务,生境支持服务在空间上呈离散化状态,而其他服务均呈集聚分布特征,且空间分异以不显著区和低-低区集群分布为主。(4)权衡/协同关系的时间变化格局上,生境支持服务-固碳释氧相关性为高度正相关,协同性系数最高,而产水-土壤保持相关性为中度负相关,权衡性系数最低;空间变化格局上,食物供给-产水、文化-固碳间空间分布均为协同关系,产水-土壤保持、固碳-产水均为权衡关系。空间格局整体以协同关系为主,权衡区与协同区空间分布有所差异。生态系统服务相关性及权衡/协同分析,有助于对研究区自然资源进行宏观调控,缓解经济发展与生态保护的矛盾。研究结果丰富了喀斯特山区生态系统恢复这一领域研究内容,有利于促进广南县资源环境的协调发展。