东洞庭湖洲滩钉螺消长规律及影响因素

目的探讨东洞庭湖区洲滩钉螺的消长规律及影响因素,为控制和消灭钉螺提供科学依据。方法选择岳阳县老港村飘尾洲为试点,收集2002～2007年6月的气象、水位资料;现场观察各年度的钉螺分布、消长及环境变化情况;分析钉螺分布的特点及其与气象、水位、环境变化的关系。结果钉螺的分布呈负二项分布,各年度的钉螺密度有一定差异,秋季钉螺密度高于春季,但差异无统计学意义（2003年例外,P〉0.05）。年平均气温、湿度、累计降雨量、日照时间和水位无明显差异（P〉0.05）,钉螺密度和钉螺死亡率与气象因素和水位无明显相关（P〉0.05）,但地理环境变化和人畜活动会对钉螺的分布产生一定程度的影响。结论一般自然情况下,东洞庭湖区的气候和水位相对稳定,对洲滩钉螺的分布和消长无明显影响,影响钉螺孳生分布的主要因素是地理环境变化和人畜活动。

Impact factors on snail distrbufion and survival in the grass beaches of East Dongting Lake

Objective To understand impact factors on distribution and status of the snails in the grass beach in the East Dongting Lake as to provide basis for snail control. Methods To select Piaowei grass beach outside dike of Laogang village in Yueyang county for a pilot, The data of meteorology （temperature, rainfall, humidity, sunlight hours, etc） and waterline from 2002 to June 2007 were collected. The snail distribution and environmental change were investigated from 2003 to Spring 2007, its correlation with meteorology, waterline and environmental changes were analyzed. Results The snail was negative binomial distribution. The results showed that there were difference in the density of snails and the snail density in the autumn were higher than that in the spring among the years from 2003 to 2006, but there was no significantly difference （except 2003, P〈0.05）. The annual average temperature, air humidity, total rainfall, sunlight hours and waterline had no sig- nificantly difference each year （P〉0.05）. The density and mortality of snails had no significantly correlation with meteorological factors and waterline （P〉0.05）. However, the geographical environmental changes, which especially artificial, and livestock activities had a certain degree of impact on the distribution of snails. Conclu- sion The climate and waterline were relatively stable in the East Dongting Lake under customary natural con- ditions,and had no effect on the distribution and status of the snails in the grass beach.The key impact factors were the geographical and environmental changes for people and livestock activities.