中文摘要：

植被波动是植被动态学的重要组成部分,中国北方农牧交错带草地植被波动特征较南方森林群落波动存在较大差异.该文在生态学、统计学的基础上,结合草地植被特征,对草地植被波动及波动率进行定义,并首次组建了草地植被波动测度公式,同时采用专家评分法确定波动系数.在波动率公式构建的基础上,以宁夏盐池县为例,研究北方农牧交错带草地植被数量波动及波动率.结果表明,盐池县2002—2006年草地植被波动率正向波动2003年最大,为0.685,是近年来植被生长状况最好的一年;负向波动以2005年的-1.098的绝对值最大,表明2005年是近年来植被生长状况最差的一年.

英文摘要：

Vegetation fluctuation is an important part of vegetation dynamics.The characters of vegetation fluctuation are quite different between the grassland community and the forestry community.Based on the meanings of ecology and statistics,the grassland vegetation fluctuation and its fluctuation ratio were defined,the fluctuation ratio was built at the first time,and the fluctuation coefficients were specified by the method of expert weighting.The grassland vegetation quantitative fluctuation and its fluctuation ratio between year 2002 and 2006 in Yanchi County,Ningxia of northwestern China,in the north farming-pastoral ecotones were studied.Results showed that the biggest positive fluctuation ratio was 0.685,meaning the best vegetation growth during recent years,which was in 2003.While the most negative fluctuation ratio was-1.098,meaning the worst vegetation growth during this period,which was in 2005.