三峡库区香溪河消落带植被多样性及分布格局研究

研究三峡大坝蓄水10 a后香溪河消落带不同高程区域植被的物种组成、群落多样性及其空间分布特征,旨在为库区消落带生态修复中的物种选择、植被群落重建提供依据。研究结果发现:(1)香溪河消落带植被以一年生草本植物为主,物种组成比较简单。植物种群空间分布分析表明,优势种种群均属于聚集分布;(2)随着高程的增加,α多样性指数中Patrick丰富度、Shannon-wiener多样性和Pielou均匀度呈增加趋势,而Simpson优势度则与其它三个指数相反呈递减的趋势;而β多样性指数中Cody指数、Wilson-Shmida指数、Jaccard指数和Sorenson 指数均呈增加趋势;(3)推荐狗牙根、马唐、狗尾草和香附子4种植物作为三峡库区香溪河消落带植被恢复的备选草本物种。

DIVERSITY AND SPATIAL DISTRIBUTION OF VEGETATION FROM THE WATER-LEVEL FLUCTUATION ZONE OF THE XIANGXI RIVER IN THE THREE GORGES RESERVOIR AREA

Vegetations at different elevations from the water-level fluctuation zone (WLFZ) of Xiangxi River in the Three Gorges Reservoir (TGR) area were collected with quadrat sampling method to assess species composition, community diversity and spatial distribution characteristics 10 years after the TGR impoundment in 2003. The objectives of this study were to provide scientific basis on species selection and plant community reconstruction in ecological restoration of WLFZ in TGR area. The results show that: (1) the main plant types in the study area were annual herbs, species composition was relatively simple. The spatial distribution of all the dominant populations belongs to the type of aggregated distribution; (2) As the elevation increased, most of the α and β diversity indexes i.e., Patrick richness, Shannon-wiener diversity, and Pielou evenness tended to increase, while the other α diversity indexes including Simpson diversity decreased. Among the β diversity indexes, Cody index, Wilson Shmida index, Jaccard index and Sorenson index all showed an increasing trend; (3) Cynodon dactylon, Digitaria Sanguinalis, Setaria viridis and Cyperus rotundus are recommended as alternative herbaceous species to be used in plant community reconstruction in the ecological restoration of the WLFZ of Xiangxi River in the TGR area.