中文摘要：

文章以四川仁寿山丘疫区157个样方钉螺密度、草本层特征调查数据为基础,采用方差、X2分统计度量、Ocihiai、Dice、Jaccaed、Pccc等系列技术分析法,研究了钉螺生境指示植物及其种间联结度。结果显示：在85个草本群落中,与钉螺有极显著正连接的有水芹、水金凤、毛茛、拉拉藤、空心莲子草、广布野豌豆6种,显著正连接的有五朵云、蜈蚣草、碎米荠、葎草等4种;有极显著负连接的有野蔷薇、苔草、金星蕨等3种,显著负连接的种类有凤尾蕨1种;Pearson相关分析表明,土壤水分含量、土地利用类型是决定钉螺分布密度的两大关键因子;Ocihiai、Dice、Jaccaed、Pccc种间系数达到一定阈值才能达到正连接或负连接的水平,四个系数与X2拟合均呈线抛物线关系;钉螺生境可分划分为极度适生、一般适生与不适生三类,后者是前者退化与灭螺改造的结果;林业血防生态工程改造效果可用钉螺不适生来描述,其标志为正连接指示植物消失而负连接指示植物出现,钉螺指示植物可用于作钉螺生境识别,也可用作林业血防生态工程模式林的效果评价。

英文摘要：

Based on the survey data of oncomelania density and herb layer characteristics at 157 quadrats（snail endemic area） located in Renshou country of Sichuan province,the indicator plants of snail habitat and interspecies association degree with the oncomelania habitats were investigated by using the methods such as variance analysis,X2 points statistical measures,Ocihiai,Dice,Jaccaed,Pccc,etc.The results show that in the 85 herbaceous plant communities,6 species（Oenanthe javanica,Impatiens uliginosa,Ranunculus japonicus.,Galium aparine var.tenerum,Alligator alternanthera,Vicia cracca）,had a very significant positive association with snail,4 species（Rosa multiflora,Carex tristachya,Parathelypteris glanduligera and Pteris multifida had a negative association with snail;3 species（Rosa multiflora,sedge,marsh fern） had a highly significant negative correlation with oncomelania,Pteris majestica had a negative correlation;but 71 kinds of species had no significant association to oncomelania.Pearson relation analyses indicate that the content of soil water and land use types were two key factors of determining the snail density and distribution.After analysis,it was found that Ocihiai,Dice,Jaccaed,Pccc for association index among species reached the level of positive and negative association while these indexes reached a certain threshold,and these processes accorded with a parabolic relation between four indexes and X2.Snail habitats were classified into three kinds： extreme adaptation,common adaptation and no adaptation,the last was the consequence that the extreme habitat degraded,reestablished after snail-killed forestation.The reconstructed effects of the forest for schistosome prevention could be described by using the no adaptation to snail,and its symbol was that the positive species disappeared and the negative association species occurred.Thus,the snail index species could be used to distinguish different snail habitats,also to evaluated the effects of mode forest for forestation and schistosome pre