西江流域生态脆弱性时空分异及其驱动机制研究

流域作为人口、资源、资本都相对集中的水文单元,其生态系统结构的稳定性是区域社会经济发展的基础。流域在生态系统演变及人类频繁活动的共同胁迫下,生境敏感性增强,脆弱易损。本文以广西西江流域为例,通过对其生态脆弱性成因机制分析,依循“敏感性-压力度-恢复力”评估框架,选取11个指标构建完成流域生态脆弱性评价指标体系,以GIS技术为支撑,采用空间主成分分析法和差值法对生态脆弱性指数进行计算与分析,探究2000-2010年广西西江流域生态脆弱性时空变化特征。基于地理探测器的因子探测和交互探测模块分析各影响因子对流域生态脆弱性结果的解释力及因子交互作用对流域生境脆弱性变化的驱动机制。结果表明:① 2000-2010年,广西西江流域生态脆弱性指数多年平均值为0.69,整体处于中度脆弱状态。空间上,流域生态脆弱性表现为中部高于四周,由城市核心区往外逐步减弱的格局特征,研究时段内流域生态脆弱性综合指数多年平均值最大的为贵港市（3.40）,最小的为百色市（2.23）;时间上,10年间,流域整体生态脆弱性呈现轻微恶化的趋势,2005年流域中部及东部地区受高温影响,导致2005年流域生态脆弱性指数整体高于其他两年;② 6个因子对流域生态脆弱性的解释力强度为生物丰度指数（0.475）>高温季节温度（0.340）>植被覆盖度（0.211）>NPP（0.183）>降雨侵蚀力（0.098）>汛期降雨量（0.030）,因子交互协同作用后对结果解释力增强。

Spatial and Temporal Differentiation of Ecological Vulnerability of Xijiang River in Guangxi and Its Driving Mechanism

As a hydrologic unit with dense population, abundant resource and intensive capital, the stability of ecosystem structure of a basin lays the foundation of regional economy's development. Influenced by ecosystem's evolution together with human being's activities, the basin environment becomes more and more sensitive and vulnerable. In case of Xijiang River in Guangxi, the thesis is to make an analysis on the cause of its ecological vulnerability and construct evaluation indexes system with eleven indices under the framework of sensitivity-pressure-recovery. Supported by GIS technology, the ecological vulnerability index（EVI）was calculated and analyzed by Principal Component Analysis and difference method, which probes into the spatial and temporal characteristics of ecological vulnerability change from 2000 to 2010. Based on the factor and the interaction detect modules of geographical detector, it aims to analyze the explanatory power of impact factors on ecological vulnerability and the driving forces of factor interaction to the changes of ecological vulnerability in the basin. The results are as following: from 2000 to 2010, the ecological vulnerability index means kept at 0.69 for years, which was at moderate vulnerability. Spatially, the central basin is more sensitive than the surround area showing a declining trend from center to suburbs. The maximum of the average ecological vulnerability composite index of the whole basin for 2000-2010, is 3.40 at Guigang City. The minimum is 2.23 at Baise City. During the past ten years, the ecological fragility of the basin showed a slight deterioration. In year 2005, central and eastern parts of the basin were influenced by high temperature, which led to the higher ecological vulnerability comprehensive index in 2005 than other years. The order of the explanatory power intensity of the six factors on the ecological vulnerability is as follows: biological abundance index (0.475)>temperature at high temperature season (0.340)>vegetation coverage (0.211)>NPP (0.183)>rainfall erosivity (0.098)>Rainfall in flood season (0.030), and the explanatory power on results will be strengthened by factors cooperative interaction.