Determination of ecological water-level in the eastern Lake Dongting with hydrological alterations

Abstract

东洞庭湖湿地具有重要生态意义.基于东洞庭湖湿地退化的现实,认为气候变化、人类活动等因素造成水文序列发生突变,湿地生态系统适应突变前的水文环境.以城陵矶水文站1952-2006年月平均水位序列为分析对象,通过滑动T检验法找到序列的最可能突变点,以该点对序列进行分割,以变异前的月平均水位序列为对象,拟合月平均水位的最适合概率分布函数,认为概率最高处的月平均水位是区域生态水位.研究结果表明,城陵矶水文站的水位时间序列发生显著变化;与其他方法相比,本文确定的东洞庭湖湿地生态水位具有一定的合理性,对东洞庭湖湿地生态系统修复具有一定的指导意义.;The eastern Lake Dongting wetland is of great importance worldwide.It has been suffered from progressive degradation lately.Wetland ecosystem is considered to be adapted to hydrological sequence before alteration caused by climate changes and human related activities.Average monthly water-level of three hydrological stations in the Lake Dongting region were analyzed in this study to obtain ecological water-level.The point of the highest T statistic value calculated by moving T-test method was considered to be the alteration point.The sequence was then divided into two parts.The subsequence before alteration point was used to find the most fitted probability distribution function.The ecological water-level was considered to be the average monthly water-level of the highest probability of the probability distribution function.The results indicate that average monthly water-level has been alternated, and the ecological water-level determined in this paper is reasonable and can provide some guides to the restoration of the Lake Dongting wetland.