三峡工程运行后长江中游君山段江滩钉螺监测结果分析

目的  观察长江中游湖南君山段江滩钉螺分布的变化，分析三峡工程运行后钉螺分布的影响因素。 方法  选择具有代表性的4块江滩作为监测点，开展钉螺纵向监测，并收集三峡工程运行前后的水情、泥沙等资料信息。 结果  2003~2015年，江滩钉螺分布范围缩小了74.77%，面积减少了72.56%，活螺平均密度下降了97.20%，感染螺平均密度下降至0。 结论  三峡工程运行后长江中游湖南君山段江滩钉螺分布范围、分布区域面积、活螺平均密度和感染螺平均密度均呈整体下降趋势。

Analysis on the distribution of Oncomelania hupensis snails in the marshlands at the middle reaches of Yangtze River along Junshan area after full operation of the Three Gorges Project

Objective  To investigate the changes of Oncomelania hupensis snails in the marshlands at the middle reaches of Yangtze River along Junshan area, Hunan Province, after the Three Gorges Project being completed and fully functional. Methods  Longitudinal monitoring on the snail prevalence was performed in the four distinctive marshlands, and corresponding data were collected on the changes of water levels and silt contents at the middle and lower reaches of Yangtze River before and fully functional Three Gorges Project. Results  The marshlands with snail distribution and areas of marshlands were reduced by 74.77% and 72.56%, respectively, from 2003 to 2015. The density of live snails was decreased by 97.20% and infected snails were not found in 2015. Conclusion  The areas with snail prevalence and snail distribution as well as average density of living snails and infected snails tend to decline in general at the middle reaches along Junshan area of Hunan Province after the Three Gorges project becoming fully functional.