Spatiotemporal evolution of land transportation networks and accessibility in inland mountainous areas 1917-2017:A case study of Southwest China

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.

Geographical Differences and Influencing Factors of Rural Energy Consumption in Southwest Mountain Areas in China:A Case Study of Zhaotong City

China is a mountainous country,and Southwest mountain areas cover the most mountain areas in China and have the most serious problems.Taking Zhaotong city as the study area,based on 902 rural household questionnaires of 11 villages in 2 counties and Tobit model,this paper analyzes the geographical differences and influencing factors of energy consumption for non-production purposes of rural households living in different terrain conditions.This research finds that:(1) Coal takes up the main part of energy consumption in valley areas and coal consumption is mainly affected by per capita cultivated land area,household income,proportion of rural household energy expenditure in total expenditure,coal price,and family population size.Firewood takes up the main part of energy consumption in high mountain areas and firewood consumption is mainly affected by per capita firewood forest area,distance to purchase coal,household income,electricity price,and coal price.(2) Only when the distance is greater than 20 kilometers,that is the average distance of rural households living in middle mountain areas(1,600m^1,800m) to purchase coal,the transportation condition has a significant impact on coal consumption.(3) In high mountain areas,prices of coal and electricity are the main factors influencing energy consumption choice of rural households.Too high prices of coal and electricity would to some extent lead rural households to choose firewood as the main energy consumption type.Compared to coal,rural households prefer to choose electricity.

CONSULTATIVE RECOMMENDATIONS ON SUSTAINABLE DEVELOPMENT IN KARST AND ROCK-NAKED MOUNTAIN AREAS OF SOUTHWEST CHINA

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".

Experience and Methods for Maize Regional Experiment in Guizhou Mountainous Areas

Maize regional experiment is a an intermediate link for overall assessment and comprehensive evaluation on yielding ability, stable yield, stress, adaptability, and quality traits of new maize varieties in different ecological conditions. It is an essential process for determining whether the new maize varieties can pass the ex- amination and approval for extension. Besides, regional experiment is an important link connecting agricultural scientific researches and agricultural production. In addi- tion, it is a scientific basis for extension and application of new maize varieties in a region. Therefore, the maize regional experiment is of the utmost importance.

Analysis on Characteristics of Architectural Environment of Traditional Villages in Southwest Mountainous Area:Taking Heijing Ancient Town of Chuxiong as an Example

The formation of the ancient town of Heijing conforms to the natural conditions and local conditions,and makes effective use of the natural mountains,water bodies,trees and other resources of the ancient town,so that the ancient town and nature rely on each other and unify harmoniously.Through the analysis of the environmental characteristics of the ancient town,this paper further explores its cultural connotation.

Study on Soil Erosion Model Under Different Slopes in Southwest Karst Mountain Area

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.

Emergency road network structure and planning optimization in mountainous regions in Southwest China under earthquake scenarios

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.

Savoring a Sea Of Flowers

A sea of rhododendrons in Guizhou Province attracts visitors from all over the country.Every summer,the mountains in southwest China’s Guizhou Province are transformed into a sea of rhododendrons,creating spectacular scenery that attracts visitors from all over the country.

Research on Auto-Classification Method of Remote Sensing Images in Mountainous Areas——An Application in Southwest of China

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.

基于InVEST模型的贵州山区不同地貌区生境退化程度评估

基于2012年土地利用数据,利用InVEST生境质量模型对贵州省麻江县低山丘陵、岩溶槽谷和中山峡谷3种地貌类型区的生境退化程度进行评价。结果表明:3种地貌类型区的主导土地利用类型均为耕地和林地,而草地、城镇工矿用地、农村居民点和水域相对较小。平均生境退化程度为低山丘陵>岩溶槽谷>中山峡谷。低山丘陵生境退化程度高值和低值分别分布于中东部河谷和西部山区。岩溶槽谷生境退化程度高值和低值分别分布于中部、南部槽谷底部和槽谷两侧。中山峡谷生境退化程度高值和低值分别分布于中北部峡谷底部和峡谷两侧高山。随坡度增加,3种地貌区的平均生境退化程度降低。不同地貌类型区的平均生境退化程度在各坡度带变化趋势亦有所不同。

西南山区大型水电工程库岸滑坡InSAR早期识别与监测研究进展

我国西南山区大型水电工程大量建设于金沙江、澜沧江、雅砻江流域,但是这些流域复杂的地层、岩性、构造、水文等地质条件导致水电工程库岸滑坡灾害分布广泛,多发频发。合成孔径雷达干涉测量(InSAR)技术凭借其覆盖范围广、监测精度高、不受云雾遮挡等特点为水电工程库岸滑坡早期识别与监测带来了新的机遇,在近年来得到水电工程建设及库岸地质灾害防治相关领域的极大重视。基于此,对西南山区大型水电工程库岸滑坡InSAR早期识别与监测的应用概况进行了梳理,从研究时间、研究内容、研究对象等多角度进行了分析;对水电工程库岸滑坡InSAR早期识别与监测技术的研究现状、研究热点进行了归纳与总结,揭示了以白鹤滩水电站为里程碑,水电工程库岸滑坡早期识别与监测目前已开始进入InSAR技术应用与研究的爆发阶段;最后,探讨了水电工程全生命周期(蓄水前阶段、蓄水阶段、蓄水后阶段)对InSAR技术的不同应用需求与算法适用性。随着SAR数据质量提升与算法进步,InSAR技术必将常规化地参与到水电工程全生命周期库岸滑坡的识别与监测工作中,为水电工程库岸滑坡的早期识别、监测预警、触发机理研究及灾害防治等提供重要支撑,提升我国水电工程库岸滑坡地质灾害防治能力。

Hydrogeochemistry of toxic metals in Au-As-Hg-Tl mineralized area in southwest Guizhou Province, China

THE environmental geochemistry problems during the processes of mining activities are intensively considered by scientists worldwide, and the hydrogeochemistry presents an important implication of toxic metalcontamination related to mining activities. The hydrogeochemistry due to mining activities and naturalmineralized processes present some differences whose comparison can indicate a good understanding of theinfluence of mining on the environment. This ongoing study aims at the hydrogeochemistry of toxic metals in the Au-As-Hg-Tl metallogenicbelt of Huijiabao anticline in southwest Guizhou, China. The presently-mined Lanmuchang mercury-thallium deposit with a Hg-mining history of about 350 years containing one of the world’s highest concentration of thallium and the to-be-mined Yanshang gold deposit enriching high concentration of toxic metals have been chosen to study the hydrogeochemistry of toxic metals. The groundwater samples werecollected from the shallow aquifer in terms of spring, domestic well and karstic cave whereas the surfacewater was only sampled downside the surface drainage leaching the mine waste at Lanmuchang. All

西南山区乡村贫困地域系统时空演化格局研究——以云南省镇沅县为例

在梳理总结国内外关于贫困地理与农村多维空间贫困、乡村地域系统与贫困地域系统理论前沿研究的基础上,提出“乡村贫困地域系统”研究视角,并对乡村贫困地域系统理论内涵进行了初步探析.以云南省镇沅县109个村域为评价分析单元,构建了乡村贫困地域系统演化发展评价指标体系,设计了乡村贫困地域系统演化发展指数测度模型和基于“时空立方体—新兴时空热点分析”的时空演化模式识别方法.研究显示:(1)镇沅县2013-2021年乡村贫困地域系统演化时序阶段性特征经历了“差异波动演化(2013-2015年)—快速演化(2016-2019年)—增长滞缓趋稳(2020-2021年)”3个主要阶段.(2)镇沅县乡村贫困地域系统时空演化模式以连续热点模式为主,加强的热点模式呈零星分布,表征2013-2021年镇沅县乡村贫困地域系统整体上经历了较快且连续稳定的减贫演化过程,是减贫政策普惠作用在时空演化模式上的具体表现;连续冷点模式和持续冷点模式呈现出县域东西两端集聚分布态势.(3)多维空间贫困陷阱主要集中在和平镇、者东镇、振太镇的部分村域,相关村域脱贫稳定性相对较差、返贫风险较高.乡村发展是乡村地域系统循环累积与动态演化的结果,深入刻画分析乡村贫困地域系统时空演化格局与特征,对于科学推动脱贫地区转型发展具有重要意义.

西南山区铁路客运专线隧道底鼓病害变形监测研究

西南山区铁路客运专线具有高桥隧比、沿线地质条件复杂恶劣等特征,在建设和运营过程中易出现各类工程病害。文章基于某隧道底鼓变形病害,设计并开展包含围岩变形、仰拱受力和道床板沉降变形3个监测指标的隧道变形监测方案。通过对监测数据进行分析,获取隧道和围岩受力变形的演化规律,据此提出后续加密轨道几何形位静态、动态检测和衬砌结构贯通裂缝观测、实施列车降速运行等处理措施。相关研究可为该客运专线的安全运营提供有力保障,同时为类似工程隧道病害的监测和整治工作提供有益参考。

景观功能视角下的西南山区农业景观格局演变研究——以重庆市石柱县为例

鉴于中国西南山区农业生态环境的脆弱性与敏感性,解析该地区农业景观时空演变特征对合理利用农业景观资源和保护生态环境具有重要的理论意义.以重庆市石柱县为例,采用景观利用图谱、地形位分布指数、景观转移矩阵等方法,从景观功能视角开展西南山区农业景观格局演变特征分析.研究表明:①农业景观呈现出“三增一减”的变化趋势,即生活型和拓展型农业景观面积呈增长态势,生态型农业景观面积呈波动变化趋势;生产型农业景观面积持续下降.农业景观变化主要表现为生产型向生态型、生活型、拓展型农业景观转化;生态型向生活型、生产型、拓展型农业景观转化.②石柱县生态型农业景观主要分布在高等级地形位,生产型农业景观逐渐向高程和坡度较高的地形位移动,生活型农业景观主要分布在低、中低等级地形位上,拓展型农业景观逐渐向较高地形位转移.③坡度、高程等是导致研究区农业景观格局演变的主要环境因素;而农业人口、农民人均纯收入、第一产业占比等是农业景观格局演变重要的人文驱动因素.

明清时期武陵山区农村经济发展探析——以黔东北地区为中心

随着改土归流的不断深入、国家权力的不断延伸以及外来移民的大量涌入,明清时期武陵山区的农村经济有了较大发展,具体表现在:农业生产技术有了较大提高,农业结构得到一定调整;农村手工业的进步较为明显,推动了山地资源的商品化生产;农村商品经济不断活跃,促进了农村市场的扩大。明清时期武陵山区农村经济的发展,为该区域其他社会事业的发展奠定了良好的经济基础,也为当今经济发展提供了历史借鉴和启示。

贵州喀斯特山区农业生态效率测度及影响因素研究——基于生态系统服务改进的对比分析

以期望产出是否包括农业生态系统服务,对贵州喀斯特山区农业生态效率进行对比分析,以期为推动该区农业绿色发展提供理论参考与数据支持。采用超效率SBM模型、GML指数测度2000—2019年贵州9个市(州)2种农业生态效率,并利用Tobit回归模型探讨其影响因素。结果表明:①传统的农业生态效率只有贵阳有效,期望产出考虑了农业生态系统服务后,除六盘水、安顺、黔西南及黔南外,其余市州农业生态效率均值进入到有效区。②研究期内贵州传统的农业全要素生产率(GML)年均增长2%,尤其是2012年以后GML指数增长明显。除了遵义、黔东南和铜仁,其余市州传统的农业全要素生产率(GML)均大于1,各市州农业生态效率提高主要依靠技术进步提升带动。除了遵义和铜仁,其余各市州改进的GML指数均较传统的有所降低。③产业结构、财政支农水平、农业机械化密度与传统和改进的农业生态效率均呈正相关,农民收入水平、化肥使用强度与传统和改进的传统农业生态效率都呈负相关,人均耕地水平与植被覆盖度与改进的农业生态效率呈正相关,但与传统的农业生态效率呈负相关。

生态脆弱区公路选线优化及生态敏感性研究——以贵州省黔东南州玉屏至镇远公路为例

大规模交通基础设施的快速发展加剧了生态风险,尤其是生态脆弱区的公路建设,易对沿线生物多样性及生态系统构成重大威胁,如何填补这一空白,更好地优化公路选线仍缺乏普遍研究。本研究以贵州省黔东南州玉屏至镇远公路选线为例,采取客观、定量的评价方法分析公路沿线生态稳定性,通过构建公路生态敏感性评价体系,运用层次分析法(AHP)及ArcGIS空间加权叠加分析,指导其在生态脆弱区的选线优化,有效防止生态系统的进一步破碎和丧失。结果表明:1)从高程(B1)、坡度(B2)、坡向(B3)、水源保护(B4)、土地利用现状(B5)、风景名胜资源保护(B6)、植被覆盖度(B7)、景观破碎度(B8)、地质灾害(B9)9个指标进行评价,权重值由大到小为B7>B1>B4>B8>B5>B2>B9>B6>B3,表明植被覆盖度对公路生态敏感性影响最大,坡向影响最小。2)玉屏至镇远公路生态敏感性分值为1.60~5.62,高敏感区和中敏感区分别占10.72%和25.84%。3)对传统公路选线(B线)与基于生态敏感性选线(K线)指标对比,K线生态敏感性(4.34)低于B线(4.58),提出了不同路段工程建设适宜性与生态恢复策略。本研究为生态脆弱区公路选线提供了科学依据,并可推广至其他领域绿色基础设施的规划与实践。

“自然-人文”融合视角下的西南山区小流域划分与整合

【目的】采用“自然-人文”融合的视角,结合人文要素界定小流域划分阈值,强化小流域划分研究的人文特征,为以小流域为基本单元的山区开展国土空间开发和社会经济建设提供区划方案支持。【方法】根据小流域自然水文过程和人文属性因素,利用流域面积法结合均值变点法及边界重叠度概念,以我国西南山区为例,对研究区内6个流域试验区进行小流域划分阈值测算,在得到最佳阈值的基础上,对西南山区以小流域为单元进行划分,并整合划分结果,分析、整合结果的数量与空间特征,提出一种山区小流域划分的融合方法。【结果】①西南山区小流域划分的最佳阈值为30.00 km^(2);②西南山区小流域数量为16075个,面积范围为25.07~431.82 km^(2);③从面积来看,小于50.00 km^(2)的小流域为8702个,占比54.13%,介于50.00~100.00 km^(2)的小流域为5358个,占比33.33%,大于100.00 km^(2)的小流域为2015个,占比12.53%,基本符合当前水利部要求。【结论】通过西南山区实测验证,本研究提出的山区小流域划分与整合方法在结果上能体现小流域的自然与人文属性特征,较好符合当前山区组织单元管理的需要,可为山区小流域区划提供方法借鉴。