基于地理探测器的江西省万安县生态脆弱性时空演变及驱动力分析

Temporal and Spatial Evolutions and Its Driving Factors of Ecological Vulnerability in Wan'an County of Jiangxi Province Based on Geogdetector

[目的]对江西省万安县生态脆弱性近30a的脆弱性进行定量研究,为县级土地脆弱性定量评价提供借鉴方法,以此促进县级社会—经济—生态可持续发展。[方法]运用1987,1995和2015年3期遥感影像数据,在分析生态脆弱性概念与评价方法的基础上,依循"压力—状态—响应"评估框架,选取景观分维数、破碎度、优势度、景观适应度4个景观格局指数,以及人类活动干扰指数、植被覆盖度指数、地形指数、景观类型指数,从生态压力度、敏感度、恢复力3个方面出发运用熵权灰色关联法构建生态脆弱性评价模型,基于格网尺度对万安县生态脆弱性进行动态评价和分析。[结果]1987—2015年万安县生态脆弱性不断加剧,其中存在68.72%的样本区生态脆弱度指数增大。通过万安县生态脆弱性分布图和趋势图可知,全县生态脆弱度高值区域集中在中北部地区而低值区集中于南部和西北部。采用空间自相关分析法分析万安县土地生态脆弱性指数空间上的集聚特征和显著性,1987—2015年万安县土地生态脆弱性存在较高的空间自相关性,空间自相关性呈现上升趋势。运用地理探测器方法,表明万安县生态脆弱性主要驱动因素是乡镇人均纯收入、单位耕地面积化肥施用量和非农业人口比重。[结论]研究区生态环境严峻,亟需针对万安县资源、气候、地形、土壤等条件,合理规划用地,科学系统划分生态功能区。

[Objective]The ecological vulnerability of Wan’an county,Jiangxi Province,was quantitatively studied in order to provide a reference for the quantitative evaluation of land vulnerability at county level,so as to promote the sustainable development of social-economy-ecological environment.[Methods]The paper took Wan’an county,Jiangxi Province,as study area,to construct natural ecosystem vulnerability assessment model using the entropy and gray correlation analysis methods from three aspects,i.e.,ecological supporting pressure,ecosystem sensitivity and ecological resilience,in accordance with the“pressure-state-response”assessment framework.Landscape fractal dimension,fragmentation,dominance,landscape adaptability index,human disturbance intensity,vegetation cover,topographic index and landscape type indexes and data of remote sensing of 1987,1995 and 2015 were used.The ecological vulnerability of Wan’an County was analyzed and assessed dynamically based on grid scale.[Results]The results showed that the land ecological vulnerability was exacerbated increasingly in 1987-2015 and 68.72%of our research area was in an increased ecological vulnerability.The distribution and trend map of land ecological vulnerability showed that high value areas of ecological vulnerability were concentrated in the central and the northern regions,while low value areas were concentrated in the south and the northwest.Method of spatial analysis were applied to analyze spatial cluster characteristics and the significance of ecological vulnerability.The spatial autocorrelation analysis revealed that the landscape vulnerability had high and increased spatial autocorrelation in 1987-2015.The main driving factors of ecological vulnerability in Wan’an County were per capita net income,the amount of fertilizer of per unit cultivated area and non-agricultural population proportion.[Conclusion]The ecological environment of the study area was severe.It was necessary to plan for rational land use and arrange the ecological functional areas according to the conditions in resources,climate,terrain and soil of Wan’an County.