Abstract: Objective To study the reasons of natural death of Oncomelania hupensis snails in marshland by comparing the differences of environmental factors between snail marshland and non?snail marshland in East Dongting Lake schistosomiasis en? demic areas. Methods Two adjoining marshlands were selected，one was a snail marshland and another was a non?snail marsh? land. The measuring points were set by grid of“20m×20m” . The soil moisture，elevation，soil pH and temperature of the points were measured，and the snails of the points were surveyed. Results The elevation，soil pH and temperature of the snail natural death marshland were all lower than those of the snail marshland （P < 0.01） . The soil moisture，elevation，soil pH and temperature of different snail densities in the snail marshland were different （P < 0.05） . The soil moisture of the non?snail group was higher than that of other four groups（P < 0.01） and the soil moisture of the group with 0-11 snails per frame was lower than that of other four groups（P < 0.01） . The elevation of the group with 0-11 snails per frame was lower than that of the group with 24-39 snails per frame and the group with more than 39 snails per frame（P < 0.05） . The soil pH of the group without snails was higher than that of other four groups（P < 0.01）and the soil temperature of the group with 0-11 snails per frame was lower than that of the group with 24-39 snails per frame. The differences of soil moisture and elevation of different death snail densities were not significant， while the differences of soil pH and temperature were significant. The soil pH of the non?snail died group was higher than that of the 2?died，3?died and more than 3?died groups（P < 0.05） . The soil temperature of the non?snail died group was higher than that of other four groups （P < 0.05） . Conclusion The elevation，soil pH and soil temperature within the range of the research may be the factors affecting the snail natural death and the soil moisture，elevation，soil pH and soil temperature may be the factors affect? ing the distribution of snails.

Key words: Oncomelania hupensis； Snail marshland；Natural death； Environmental factor

摘要： 目的 目的 比较东洞庭湖有螺洲滩和钉螺自然消亡洲滩的各环境因素的差别， 探究洲滩钉螺自然消亡的原因。方 方 法 法 选取东洞庭湖地理位置较近的有螺洲滩 （君山公园） 和钉螺自然消亡洲滩 （钱粮湖） 各1块， 20 m × 20 m网格设置检测 点， 对各检测点进行钉螺调查和钉螺死活鉴定， 同时测量检测点的高程、 土壤含水量、 pH和温度。结果 结果 钱粮湖钉螺自然 消亡洲滩的高程、 土壤pH和温度均小于君山公园有螺洲滩 （P < 0.01）； 君山公园有螺洲滩不同活螺密度的高程、 土壤水分 含量、 pH和温度均有统计学差异 （P < 0.05）， 其中无螺组的土壤中水分含量和pH高于其他有螺组 （P < 0.01）， 活螺密度为 1 ~ 12只/0.1 m2 的土壤水分含量低于其余4组 （P < 0.01）， 其高程也低于活螺密度为25 ~ 39只/0.1 m2 和> 39只/0.1 m2 的滩 地 （P < 0.01）， 无螺组的土壤pH高于其他有螺组 （P < 0.01）， 活螺密度1 ~ 12只/0.1 m2 的土壤温度低于25 ~ 39只/0.1 m2 的 温度 （P < 0.05）； 有螺洲滩不同死螺密度组的水分含量和高程差异没有意义 （P > 0.05）， 但土壤pH和温度具有显著差异 （P < 0.05）， 无钉螺死亡组的土壤pH高于死亡2只、 3只和3只以上的组 （P < 0.05）， 无钉螺死亡组土壤温度高于其余有钉螺 死亡组 （P < 0.05）。结论 结论 在东洞庭湖， 洲滩的高程、 土壤含水量、 pH值和温度可能是影响钉螺分布的因素， 而高程、 土壤 pH和温度则可能是影响钉螺自然消亡的因素之一。

关键词: 钉螺； 有螺洲滩； 自然消亡； 环境因素