水位变动下三峡库区消落带植物群落特征

水位变动是湿地的基本特征之一，对湿地生态系统意义重大。为了解水位变动对三峡库区消落带植物群落的影响，于2010年8月对白夹溪消落带植物群落进行调查，采用TWINSPAN分类法对植物群落进行分类。结果表明:共发现维管植物85种，隶属34科70属；植物群落可划分为18个类型，狗牙根等5种群落为白夹溪消落带代表性植物群落；随着淹水程度的加深，群落组成呈现出由旱生植物到湿生植物的过渡趋势；植物群落香农指数、均匀度指数、丰富度指数和生物量指数随水位梯度呈“∧”型变化趋势，辛普森指数呈“∨”型变化趋势。与156 m蓄水周期相比，植物物种数量、群落类型及组成、多样性均发生改变。水位变动是消落带新生湿地植物群落变化的主要驱动因子

EFFECTS OF WATER LEVEL FLUCTUATION ON PLANT COMMUNITIES IN THE LITTORAL ZONE OF THE THREE GORGES RESERVOIR

The water level fluctuation is one of the basic characteristics of wetland ecosystem.This paper aimed to study the effects of water level fluctuation on the characters of plant community in the littoral zone of Three Gorges Reservoir(TGR).The composition and structure of plant community of littoral zone of Baijia stream were investigated in August 2010.The results showed that there were 34 families of vascular plants including 70 genera and 85 species.The vegetations were divided into 18 community types by TWINSPAN classification,among which Ass.Cynodon dactylon and other 4 communities were the most representative plant communities.The composition of vegetation showed a transition from xerophytes to hygrophytes with the increasing of flooding intensity.Shannon index,Pielou index,Richness index and plant biomass showed a distribution of "∧" type,while Simpson index showed a distribution of "∨" type varying with the water-level fluctuation.The quantity of plant species,the composition and types of community and the diversity were different from the hydrology of 156 m.Water-level fluctuation was one of the main driving factors of vegetation change in the newly wetland.