中文摘要：

调查发现在血吸虫疫区江滩主要防洪林有枫杨林、意杨林、旱柳林和芦苇林。在每一林地内取5块样地（20m×20m），每块样地均设5个样方（1m×1m），统计林底植物种类及覆盖度，测定样地光照和土壤湿度。同时在每个样方内随机设置一平方尺（即0．11m2）的样框调查地表钉螺数并统计其死亡率。经统计分析得出：（1）疫区江滩枫杨林钉螺密度（每0．11m2内个数）与意杨林、旱柳林和芦苇林的差值置信区间分别为8．2809—18．2309、-0．7622—1．6462和5．3190-13．3809；（2）枫杨林下常见的9种植物中，益母草、蓓草、紫苏、夹竹桃、篓蒿等与钉螺呈负相关，其中夹竹桃、益母草与钉螺显著负相关，化感作用明显；藕草、水芹、鸡矢藤和木贼呈正相关；（3）枫杨林群落生态因子与钉螺的相关性表现为：最适宜于钉螺孳生的光照为5×100—15×1001x、土壤湿度为20％-40％、林底植被覆盖度为40％-70％；（4）室内对照实验显示，枫杨鲜叶0．5％浓度水浸液抑螺效果在6d后为84％，优于同浓度凋落物的42．7％钉螺死亡率。上述研究结果可为改善防洪林群落结构，增强防洪林群落抑螺效果提供参考依据。

英文摘要：

The Schistosomiasis has special harm to health. Oncomelannia hupensis is the only intermediate host of Schistosome,and the weakest link in the life cycle of Schistosome. Killing Oncomelannia hapensis can properly control Schistosomiasis, protect wetland and water resource. There are four Shelter-forest communities on the sands of the middle and lower reaches of the Yangtze River： the Pterocarya stenoptera community,the Popalus canadensis community,the Salix mastsudana community and the Phragmites commuis community. Taking five sample plots （20m × 20m） in every forest, and setting five quadrats （ 1m ×1m） in every sample plot, calculating the species of plants in the bottom of the forest and coverage,measuring sunlight and soil humidity in every sample plot. At the same time,setting a sample lattice with the size of one square foot （0.11 m2 ） in every quadrat randomly, so as to investigate the number of Oncomelania in the earth surface and calculate its death rate. By investigation and statistics,the result showed that ： （ 1 ） The reliable scope of disparity in the density （ single/0.11 m2） of Oncomelania among the Pterocarya stenoptera community and the Populus canadensis community, the Salix mastsudana community, the Phragmites commuis community on the beaches of the Yangtze River was 8. 2809--18. 2390, - 0. 7622--1. 6462 and 5. 3190--13. 3809, respectively; （2） There were 9 species familiar plants under the Pterocarya stenoptera community, and Leonurus artemisia ,Humlus scandens , Perilla frutescens , Nerium indicum ,Artemisia selengensis were representing negative correlationship and with allelopathy on the Oncomelannia hupensis , and Phalaris arundinacea , Oenanthe javanica , Paederia scandens,Equisetum hiemole were taking on positive correlationship; （3） The range of the most suitable to live in for Oncomelania was that the insolation was 5 × 100--15 × 100lx,the soil moisture was 20%--40% and the vegetation cover under the forest was 40%--70% between the ecological factors