长江干流关键点流量变化及其生态影响分析

文章详细介绍了水文变动指标IHA法32个水文参数及其生态影响,计算分析了长江干流4个关键点寸滩、宜昌、汉口和大通在"自然变化阶段"、"受人类活动干扰阶段"和多年长系列3个不同时期的多年平均月流量状况,并采用IHA法计算了各控制点的32个水文参数,确定了各参数相应的水文变化等级,分析了长江干流流量格局的变化情况及潜在的生态影响。结果表明,长江干流关键点流量格局的变化主要是:年内月平均流量1～4月枯季流量增加,6～7月汛期流量增加;寸滩和宜昌流量减少主要集中在下半年8～11月,汉口和大通流量减少的时间推迟,主要集中在10～11月;最小流量参数组的平均值增加,年最小1日流量日期均提前;干扰后呈现连续日上涨率减小,下降率增加的趋势;潜在的生态影响主要是生物多样性降低,大型水生植物丰度增加,大型无脊椎动物现存量减少和丰度减少,对产漂流性卵的鱼类影响较大,动植物生活史模式发生变化,易造成本地物种消失,外来物种入侵的后果等几个方面。

Discharge Changes and Ecosystem Influence in Critical Sections of the Yangtze River Mainstream

Indicators of hydrologic alteration method about 32 hydrologic parameters and its eco-response were introduced. Monthly discharge in 3 different periods and 32 hydrological parameters in critical control gauges of the Yangtze River were calculated and analyzed,and hydrologic alteration degrees were graded to analyze hydrologic change and ecosystem influence. Results showed that the potential ecosystem influences included the reduction of biodiversity,increase of abundance of aquatic macrophyte,decrease of abundance and biomass of macroinvertebrate,potential influence of fishes with pelagic eggs,life cycles of biology change,disappearance of native species and invasion of alien species. The study can provide a reference for quantitative analysis of eco-hydrological targets and ecological regulation of Three Gorges project,and also can promote the research of ecological regulation.