METHODS: By employing remote sensing data from 1993 to 2016 (April-June and September-November), the vegetation area of Poyang Lake and the vegetation area at different elevations were extracted and calculated. Moreover, the average daily water level data from the four hydrological stations (Hukou station, Xingzi station, Tangyin station and Kangshan station) which represent the typical state of Poyang Lake were collected from 1993 to 2016. The variance of the monthly mean water level, inundation time and the average area were analyzed by variance to find a significance level of α = 0.05.
RESULTS: According to hydrological data before and after 2003, the average water level after 2003 is significantly lower than that before 2003 in Poyang Lake. After 2003, the time of inundateing the snail breeding period was later in April to June than that before 2003, while the time of wate-falling stage in September to November moved forward after 2003 than before 2003. Of them, the lowest water level affecting the breeding and growing period of O. hupensis in the northern part of Poyang Lake decreased from 11 m to 9 m. After 2003, the expansion of meadow area in the north part of Poyang Lake was mainly concentrated in the elevation of 9-11 m, and the newly increased infested-meadow in the lake area was mainly concentrated in the north part of Poyang Lake.
CONCLUSIONS: By comparing the change of water level characteristics in different parts of the Poyang Lake area as well as changes in meadow area before and after 2003, it is found that the water level changes mainly affect the snail breeding area in the northern part of Poyang Lake. The results are helpful for improving scientific measures for snail control in Jiangxi Province. This approach could also be applicible to Dongting Lake area and other lake areas affected by water level changes and can bring significant guidance for snail control in lake areas.
方法:通过使用1993年至2016年(4月至6月和9月至11月)的遥感数据,提取并计算了鄱阳湖的植被面积和不同海拔的植被面积。此外,四个水文站(湖口站,星子站,1993年至2016年收集了代表鄱阳湖典型状态的汤阴站和康山站)。月平均水位的方差,淹没时间和平均面积进行方差分析,发现α=0.05的显著性水平。
结果:根据2003年前后的水文数据,鄱阳湖2003年以后的平均水位明显低于2003年以前。2003年以后,蜗牛繁殖期的时间在4月至6月比2003年以前晚,而9月至11月的落水期时间在2003年以后比2003年以前向前移动。其中,影响鄱阳湖北部湖北的繁殖和生长期的最低水位从11m下降到9m。2003年以后,鄱阳湖北部草甸面积的扩张主要集中在9-11m的海拔,湖区新增加的出没草甸主要集中在鄱阳湖北部。
结论:通过比较鄱阳湖不同地区水位变化特征以及2003年前后草甸面积的变化,发现水位变化主要影响鄱阳湖北部蜗牛养殖区。研究结果有助于完善江西省钉螺防治的科学措施。这种方法也适用于洞庭湖区和受水位变化影响的其他湖区,可以为湖区的蜗牛控制提供重要指导。