中文摘要：

三峡水库156m蓄水后，消落带内植物种类组成、空间分布格局以及多样性发生巨大变化。2008年7～9月对开县澎溪河及支流自夹溪沿岸海拔175m以下范围的植被进行调查：在澎溪河设置3个样带，在白夹溪设置2个样带，共108个草本样方。结果表明：共发现98种维管植物，分属于38科29属，其中水生、湿生植物52种；一年生植物和隐芽植物种类丰富，分别占52．0％和31．6％；调查区域内植被可划分为11个群丛；沿河流侧向空间梯度可分为河漫滩一年生草本植物带、苍耳带、双穗雀稗带、白茅带4个植物带；土壤含水率的变化及分布格局对消落带植物带状分布有较大影响。研究表明消落带内植物物种丰富度和多样性较低。

英文摘要：

After impounding to altitude of 156 m, species, spatial pattern and biodiversity of plant community in water-level-fluctuation zone of Three Gorges reservoir have significant changes. The plant community under altitude of 175 m beside the Pengxi River and its tributary Baijia Stream in Kaixian County was studied from July to September, 2008. 108 herb sampling quadrates along five sampling transects, three beside the Pengxi River and two beside Baijia Stream, were conducted. The results show 98 species of vascular plant belong to 38 families, 29 generas. 52 species of wetland plant have been investigated. Therophytes （ 52. 0% ） and cryptophyte （31.6% ） are the dominant compositions of Raunkiaer＇ s life. The plant community of study area belong to 11 associations. Floodplain annual herb zone, Xanthium sibiricum zone, Paspalum paspaloides zone and Imperata cylindrica zone disperse at the lateral side of the Pengxi River and Baljia stream from riparian to altitude of 175 m. The variation and pattern of soil water content significantly influence the distribution of plant community in water-level-fluctuation zone. There is a low herb biodiversity in water-lever fluctuation zone.