左江上游流域景观生态风险评价  

Landscape Ecological Risk Assessment for Upper Zuojiang River Basin

作　　者：卢远[1] 苏文静[1] 华璀[1] 汤传勇[1] 

机构地区：[1]广西师范学院资源与环境科学学院,南宁530001

出　　处：《热带地理》2010年第5期496-502,共7页Tropical Geography

基　　金：国家自然科学基金(40761027);广西师范学院博士科研启动基金项目

摘　　要：以1990年和2008年左江上游流域的土地利用数据和数字高程模型为基础,以景观干扰度、景观脆弱度为主要评价指标,构建景观生态风险评价模型,对研究区景观生态风险的时空变化特征进行评估分析。研究表明:(1)伴随着流域开发活动的加强,1990―2008年18年间,左江上游流域景观格局变化的主要特征为耕地景观显著增加,其面积比例由1990年的20.54%增加至2008年的27.59%;草地景观显著减少,其面积比例由1990的12.66%减少至2008年的3.29%;(2)受地质?地貌格局控制,流域景观生态风险的空间格局存在较大差异,峰丛洼地区?河谷平原和台地区农业景观生态风险较高,而丘陵山区的森林景观生态风险较低;(3)流域内景观生态风险水平正在逐渐增高,中、高和极高等级风险区面积分别增加9.15%、2.08%和2.15%,生态安全格局呈现显著的破碎化趋势,区域人类活动是影响景观生态风险加重和扩散的主要原因。A multi-factor model comprising the indexes of fragmentation,isolation and dominance,and vulnerability of landscape types is established to assess the landscape ecological risk（LER） in the upper Zuojiang river basin in Guangxi with 1990 and 2008 land use data and Digital Elevation Model（DEM） data.The temporal and spatial characteristics of landscape change are analyzed and the level of ecological risk is assessed.According to the calculated results,the LER levels of 1830 samples are assessed and classified into 5 grades,which are slight（≤0.338）,light（0.339～0.402）,medium（0.403～0.446）,strong（0.467～0.537）and ultra strong（ 0.538）.The research shows that：（1） In the period from 1998 to 2008,along with the activities of development,the landscape change in the upper Zuojiang river basin was characterized by persistent increase of cultivated land landscape in the valley areas,while the substantial decrease of grassland landscape in hilly areas.In 1990,the area of the cultivated land landscape within the studied region was 1259.77 km^2,and by 2008 it was 1701.89 km^2,with an increase of 442.12km^2 and a change ratio of 7.05%.In contrast,the area of grassland decreased from 841.64 km^2 in 1990 to 219.08 km^2 in 2008,with a decrease of 622.56 km^2 and a change ratio of 9.37%.（2） As a result of special geological,geomorphological differentiation,the landscape ecological risk level in the region differed obviously.The ecological risk level of agricultural landscape in peak-cluster depressions,valley plains and terrace areas was the highest,and in the natural landscape of hills and mountains was the lowest.（3） The landscape ecological risk level in the basin gradually increased,the areas of medium,strong and ultra strong LER levels in the period increased by 9.15%,2.08 and 2.15%,respectively.And the ecological security pattern tended to a significant fragmentation.Human activities are the main causes affecting the LER increase and diffusion.

关 键 词：景观格局 生态风险 峰丛洼地 丘陵山区 左江上游 

分 类 号：Q149[生物学—生态学]