论文部分内容阅读
目的比较三峡建坝前后东洞庭湖钉螺自然消亡洲滩和有螺洲滩水淹天数的差异,探究钉螺自然消亡的原因。方法选取东洞庭湖钉螺自然消亡洲滩(钱粮湖)和有螺洲滩(君山公园)各1块,以20 m×20 m机械布点,对各检测点进行螺情调查,同时测量检测点的高程以及收集相应水文站的水位数据,计算各自水淹天数。结果钱粮湖钉螺自然消亡洲滩的历年水淹天数均多于君山公园有螺洲滩(P<0.01);对于钱粮湖洲滩,钉螺自然消亡前与消亡后至建坝前水淹天数的差异无统计学意义(P>0.05),而消亡前、消亡后至建坝前的水淹天数均多于建坝后(P1<0.05,P2<0.01);三峡建坝前,钱粮湖钉螺自然消亡洲滩水淹天数多于建坝后(P<0.05),君山公园有螺洲滩水淹天数也多于建坝后(P<0.01);君山公园洲滩钉螺密度同水淹天数未见明显的相关(rs=0.008,P>0.05),所有有螺框检测点水淹天数的95%参考值范围为76~251 d。结论在东洞庭湖,水淹时间的长短和三峡大坝的建立运行可能不是钉螺自然消亡的直接原因,而后者有可能改变钉螺的分布范围。
Objective To compare the differences in days of natural subjugation seagrass and snail banks of Oncomelania in East Dongting Lake before and after the construction of the Three Gorges Dam to explore the reasons for the natural demise of Oncomelania snail. Methods One snail bank (Qianglihu Lake) and one Juxingtan (Junshan Park) were randomly selected from the eastern Dongting Lake. The snails were randomly placed on a 20 m × 20 m ground, Elevation and collection of the corresponding hydrological station water level data, calculate the number of flooding days. Results The average number of flooding days of Snail Snail bank in Qianliu Lake was more than that of Junshan Park in Junshan Park (P <0.01). The difference of days before and after the death of Snail (P <0.05). However, the number of flooding days before demise and before dam construction was more than that after damming (P <0.05, P <0.01). Before the construction of the Three Gorges, the snail There were more days of flooding in Chazhoutan than those after the dam was built (P <0.05). There were also more days of flood in Junshan Park than in the dam (P <0.01) (Rs = 0.008, P> 0.05). The reference values of 95% of all flooding days with screw-frame test points ranged from 76 to 251 days. Conclusion In East Dongting Lake, the duration of flooding and the establishment and operation of the Three Gorges Dam may not be the direct cause of the natural demise of Oncomelania, while the latter may change the distribution range of Oncomelania.