中文摘要：

广西平果喀斯特地区被假臭草入侵的群落,包括撂荒地、退耕还林幼林、公路边、荒山灌草丛4种土地利用类型.用元分析、协方差分析、线性混合效应模型、树模型研究其草本植物多样性、丰富度及影响因子.结果表明：元分析总效度为正且显著;所有区组的效度为正;撂荒地的效度为负,其他3种土地类型的效度为正;权重较大的土地类型为灌草丛.协方差分析表明,假臭草重要值、距公路距离、30 cm深含土率是影响草本植物多样性、丰富度的主要数量因素;有假臭草群落的草本植物多样性、丰富度高于无假臭草群落;土地类型对草本植物多样性影响显著,但对草本丰富度无显著影响.线性混合效应模型划分了随机效应解释率,有无假臭草、样方间误差分别解释草本Shannon指数模型50.9%、49.1%的随机效应,解释草本植物丰富度模型39.0%、61.0%的随机效应;区组和土地类型的随机效应为零.假臭草入侵分为5个等级,中度入侵的群落草本植物多样性、丰富度较高;假臭草重要值超过23.6%阈值后,草本植物多样性、丰富度均呈下降趋势.

英文摘要：

Community invaded by Praxelis clematidea in karst mountainous area of Pingguo,Guangxi Province was investigated including 4 land types,i.e. abandoned cropland,young plantation,roadside and shrub. Meta analysis,analysis of covariance,linear mixed effect model and recursive partitioning were used to analyze their herb diversity and richness in relation to environmental variables.The results showed that summary effects were positive and significant,effects of groups were positive,effect of abandoned cropland was negative,and effects of other three land types were positive,and shrub had high weight in the analysis. Analysis of covariance indicated that importance value of P. clematidea,distance to driveway and soil were the main numeric factors influencing herb diversity and herb species richness,and plots invaded had higher herb diversity and richness than those uninvaded. Land types had extremely significant impacts on herb diversity but had nothing on herb species richness. Linear mixed effect model partitioned the explained variances of random effects,factor P. clematidea present or absent and residuals respectively contributed 50. 9% and 49. 1% in Shannon model,while 39.0% and 61.0% in richness model,groups and land types contributed zero to the random effects. P. clematidea invasion could be classified into 5 levels,and modest invasion caused higher herb diversity and richness. When P. clematidea importance value was more than23.6%,the critical threshold,both herb diversity and richness declined.