中文摘要：

于2012年平水期（4月）、丰水期（8月）和枯水期（11月）对乐安河自上游至下游及入鄱阳湖区域内湿地植物群落分布和水土环境因子进行调查,分析乐安河不同水期湿地植物群落的分布特征,通过DCCA（detrended canonical correspondence analysis,除趋势典范对应分析）探讨不同水期植物群落分布特征与环境因子间的定量关系.结果表明：3个水期内共观测到湿地植物167种,不同水期植物种类及组成结构均具有显著差异.其中平水期湿地植物102种,分属于33科75属;枯水期71种,分属于27科53属;丰水期种类最少,为55种,分属于20科42属.乐安河上游处于未受矿山开采影响的对照区域内,水生植物群落分布主要受河流自然环境因素的影响.对于受重金属酸性污染影响较严重的区域,DCCA排序结果显示,水土环境中p H和Cu、Pb、Cd等重金属含量是影响植物群落分布的重要因素.其中,上游湿地植物群落分布主要受Cu含量和p H的影响;中、下游主要受水、土环境中重金属Pb、Cd的复合污染以及p H的影响.乐安河湿地植物群落分布与环境因子间具有明显的对应关系,DCCA法能准确识别影响湿地植物群落分布的关键环境因子.

英文摘要：

The quantitative relationships between plant communities and environmental factors in different water periods in the wetland between Le＇an River and Poyang Lake were investigated in this study.Samples of aquatic plant communities,water,soils and sediments from 13 sites were investigated in April,August and November of 2012,which represented the different typical water seasons of Poyang Lake.14 environmental factors in the water, soil and sediment samples at different sites were detected.Detrended Canonical Correspondence Analysis（ DCCA） was applied to explore the relationships between aquatic plant communities and environmental factors by using Canoco for Windows 4.5 software,and the sampling site environment bi-plots were drawn based on the results of DCCA.The results indicated that 167 plant species were found in all sites within the three different water seasons,and the species composition and structure were significantly different in different water periods.In total,33 families,75 genera and 102 species in the normal water period,20 families,42 genera and 55 species in the abundant water period,and 27 families,53 genera and 71 species in the low water period were found.The number of plant species was least in the abundant water period.The river natural environmental factors were the dominant impact factors were the dominant factors impacting the wetland plant community dynamics in the slightly polluted area in the upstream of the Le＇an River.However,in addition to the impact of water level and other hydrological condition factors,the structure and species of other plant communities in the severely polluted areas were also mainly affected by p H and heavy metalpollution from copper,lead,cadmium and other factors in the soil and water environment.The plant communities in the upstream riparian were impacted by copper pollution,because they were polluted severely by heavy metals acidic wastewater.The plant communities in the middle and lower reaches were mainly impacted by the combined pollution of lead a