东洞庭湖秋冬季节钉螺生存状态及其影响因素的研究

目的 研究秋冬季节钉螺种群的动态变化及水位和气象因素与钉螺消长的关系。方法 选择2007-2014年10-12月，以东洞庭湖区的草滩为现场，系统抽样查螺，同时测量调查点的高程以及收集水位和气象资料，计算各年水淹天数和开始水淹时间。描述钉螺及可能影响因素的分布情况，用多元回归模型研究水位和气象因素与钉螺密度的关系。结果 钉螺密度呈波动变化，最高值在2012年10月，为41.88只/0.1 m2；最低值在2008年11月，为1.23只/0.1 m2。死亡率最高出现在 2008年11月，为73.72 %；最低出现在2012年10月，为1.09%。多元回归模型拟合发现1月平均最低温度和开始水淹时间与ln（钉螺密度）之间存在线性关系。利用该模型计算得到的ln（钉螺密度）的预测值与实际值的相关系数为0.927（P = 0.001）。 结论 在东洞庭湖，1月份平均最低温度和开始水淹时间对当年秋冬季的钉螺密度有一定的影响。

Research on living status of Oncomelania hupensis in autumn and winter and its correlates in Eastern Dongting Lake area

Objective To explore the dynamic changes of Oncomelania hupensis snail densities in autumn and winter and the relationship between hydrological and meteorological factors and snail growth and decline. Methods From Octobers to Decembers of 2007 to 2014， a bottomland close to eastern Dongting Lake was selected as the study field. The snails and elevation of the points were surveyed， and the hydrological and meteorological data were collected. The snail densities and death rates of every month were calculated. The meteorological and hydrological data were described， and the relationship between the snail densities and associated factors were fitted by the multiple regression model. Results The snail density was highest in October 2012 （41.88 per 0.1 m2） and lowest in November 2008 （1.23 per 0.1 m2）. The snail mortality was highest in November 2008 （73.72%） and lowest in October 2012（1.09%）. The multiple regression model found a linear relationship between hydrological and meteorological factors and snail densities. The correlation coefficient between the prediction of ln（snail density） and its measurements by using this model was 0.927 （P = 0.001）. Conclusion The average minimum temperature in January and time of starting flood have an obvious influence on the snail densities in autumn and winter.