黄土高原半干旱区微尺度乡村人居环境系统脆弱性测度及时空分异——以陕西省佳县为例

Measurement and spatial-temporal differentiation of vulnerability of microscale rural human settlementsin the semi-arid region of the Loess Plateau:A case study of Jiaxian County,Shaanxi Province

从人地系统脆弱性视角着眼,基于65个样本点,451份入户调查问卷,65份村庄专题问卷,运用逼近理想解的排序法等方法探索了佳县1980-2017年微尺度乡村人居环境系统的时空分异过程。结论表明:(1)乡村人居环境系统脆弱性均值已由0.66下降至0.45,空间差异度由3.99%大幅扩大至15.31%,呈现由空间重度脆弱的均衡状态分化至中低脆弱为主体,24.62%的村庄仍处于高脆弱状态的格局。(2)居住、自然、社会子系统脆弱性显著减轻,均值分别下降至0.38、0.42、0.47,居住子系统仅余1.54%的高脆弱村庄。支撑、人类系统脆弱性均值保持或上升至0.54以上的高位,高脆弱村庄比重均超过2/3。(3)居住、自然、社会子系统由高脆弱样本村全局覆盖演化至低脆弱样本村广泛分布,而人类系统呈现由低中脆弱样本村相间分布演化至高度脆弱样本村全局覆盖的时空格局。支撑系统空间格局动荡,低脆弱等级仅集中分布于交通干线沿线、行政中心驻地样本村。

Low rainfall,fragile ecology,and economic poverty are typical characteristics of the Loess Plateau.Jia county of Yulin City,Shaanxi Province,is a typical county in the semi-arid Loess Plateau,and is the main battlefield for ecological restoration and poverty alleviation in China.Following the theory of human-land system vulnerability,using TOPSIS model,this studymeasured the vulnerability value of microscale rural human settlement and natural,dwelling,human,support and social subsystems during the four historical periods from 1980 to 2017(1980 s,2000,2008,2017)based on 65 sample villages,451 household questionnaires,and 65 thematic questionnaires for key village figures.Additionally,the spatial and temporal differentiation characteristics of vulnerability of rural human settlements in the research area,based on GIS spatial analysis technology,were also discussed,.The study results show the following.(1)The average vulnerability of rural human settlements in the 65 sample villages decreased from 0.66 to 0.45,and the vulnerabilities of dwellings,and natural and social subsystems were significantly reduced,with the mean vulnerability values for dwellings and natural and social subsystems in the 65 sample villages falling to 0.38,0.42,and 0.47,respectively.However,the mean value of support and human system vulnerability in the 65 sample villages remained unchanged or rose above 0.54.(2)Based on the 65 sample villages,the spatial differences of vulnerability of the comprehensive system and the five subsystems of rural human settlements all showed expanding trends with different ranges.Among these,spatial differences of the integrated system and the dwelling subsystem increased by nearly 12 percentage points to 15.31%and 17.88%,respectively.The natural subsystem(30.77%)had the largest spatial difference,followed by the support subsystem(21.61%),both of which increased by a factor of two compared to the 1980 s.The spatial differences in vulnerability of both human and social subsystems increased slightly,rising by only 3 percentage points since the 1980 s.(3)The comprehensive system of rural human settlements has evolved from a uniform distribution of severely vulnerable sample villages to a main distribution of sample villages with medium-and low-vulnerability,and 24.62%of the highly vulnerable sample villages existed.Dwelling,natural,and social subsystems all presented similar evolution processes,shifting from a global coverage of high-vulnerability sample villages to a widespread distribution of low-vulnerability sample villages,with only 1.54%of the high-vulnerability villages left in the dwelling subsystem.In contrast,the human subsystem evolved from a main distribution of medium-and low-vulnerability sample villages to a global coverage of high-vulnerability sample villages.Additionally,thespatial pattern of the support system is unstable,with the low vulnerability level concentrated in sample villages located along major traffic lines or in the administrative centers of towns.At present,the proportion of high-vulnerabilitysample villages of human and supporting subsystems have both been exceeded two-thirds.Based on the above findings,this study discusses the temporal and spatial process of rural human settlement vulnerability from the micro scale,which better reflects the development and unbalanced characteristics of rural human settlements.Therefore,this paper suggests that future work should not only focus on the vulnerability of the human and support subsystems,but also on spatial imbalances of the natural,support,and dwelling systems.