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目的评价洞庭湖区有螺洲滩实施开沟沥水工程后对钉螺孳生繁殖的影响。方法 2009年11月-2012年11月,选择位于东洞庭湖区的岳阳监狱和君山区有螺外洲滩,分别设为干预区和对照区2组研究现场观察区。在干预区洲滩实施开沟沥水工程,采用挖掘机开挖“井”字沟,观察该工程对洲滩土壤含水量和相对地下水位、以及对钉螺孳生繁殖的影响。对照区洲滩不采取任何措施。结果开沟沥水工程实施前,2组观察区在枯水期不同高程的洲滩土壤平均含水量均在35.56%左右。工程实施后,干预区洲滩土壤平均含水量26.53%,而对照区则为35.56%,两者差异有统计学意义(F=6.53,P<0.05);干预区不同高程相对地下水位明显低于对照区,差异有统计学意义(χ2=33.33,P<0.05)。工程实施前,干预区和对照区钉螺自然死亡率分别0.98%和0.89%,差异无统计学意义(P>0.05);工程实施后的2012年干预区未再查见钉螺和幼螺,而对照区活螺平均密度和幼螺则仍分别为29.37只/0.1 m2和213±108.45只/0.1 m2。结论在湖区有螺洲滩开沟可迅速沥干洲滩积水,显著降低洲滩土壤的含水量,改变钉螺繁殖和孳生的生态条件,从而控制钉螺的孳生繁殖。
Objective To evaluate the influence of the implementation of the ditching and draining of Loam Ditch Project on the breeding of Oncomelania snail in Dongting Lake area. Methods From November 2009 to November 2012, Yueyang Prison located in East Dongting Lake area and Rouxan Beach in Junshan District were selected as the observation sites of two groups in the intervention area and the control area respectively. In the interventional area of the bank, the trenching and draining works were implemented. Excavators were used to excavate the ditches of “well” to observe the effects of the project on the soil moisture and relative groundwater level of the beach and the breeding of snails. Control Area Beach do not take any measures. Results Before the implementation of the ditching and draining project, the average soil moisture content of the island beaches at different elevation in the dry season was 35.56%. After the implementation of the project, the average soil water content of the affected area was 26.53%, while the control area was 35.56%, the difference was statistically significant (F = 6.53, P <0.05); the relative groundwater level of different elevation in the intervention area was significantly lower than Control area, the difference was statistically significant (χ2 = 33.33, P <0.05). Before the implementation of the project, the natural mortality rates of Oncomelania snails in the intervention area and control area were 0.98% and 0.89%, respectively, with no significant difference (P> 0.05). After the implementation of the project, the snail and juvenile snails were not found again in the intervention area in 2012 The average density of live snails and young snails were still 29.37 /0.1 m2 and 213 ± 108.45 /0.1 m2 respectively. Conclusions In the lake area, the dredging of Lo Tho beach can rapidly drain the isthmus of the beach and significantly reduce the soil moisture content of the beach and change the ecological conditions of the snail breeding and breeding so as to control the snail breeding.