安庆西江长江江豚迁地保护基地河岸带植物群落结构特征
CHARACTERISTICS OF RIPARIAN PLANT COMMUNITY IN YANGTZE FINLESS PORPOISE EX-SITU RESERVE IN XIJIANG OXBOW, ANQING CITY
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摘要: 安庆西江是长江下游唯一的长江江豚(Neophocaena asiaeorientalis)迁地保护区。为了解安庆西江河岸带植物群落结构, 进而评价西江长江江豚栖息地的生境情况, 于2017年夏季对西江河岸带10个断面的植被进行了系统调查。研究结果表明, 西江河岸带植被中共有维管植物166种, 隶属于50科131属, 其中藻类植物1科1属1种, 蕨类植物1科1属2种, 种子植物48科129属163种, 以蝶形花科、菊科、禾本科为优势科, 科、属的分布类型较为丰富。对植物群落结构分析的结果显示, Shannon-Wiener指数变幅为0.213—0.899, 均值为0.629±0.399; Simpson指数变幅为0.135—0.465, 均值为0.315±0.204, 物种丰富度变化范围在3—14, 多样性指数与丰富度指数变化一致。西江河岸带植被分布还呈现出显著的空间特征, 两岸受人类活动影响较大的区域, 河岸带植被多样性指数较低; 自然区域的植物覆盖面积大, 群落多样性指数和丰富度则较高。总体而言, 西江河岸带植被物种丰富, 覆盖率高, 既可以改善水质, 又可以为小型定居性鱼类提供良好的产卵场和索饵场, 对于维持长江江豚迁地种群的栖息和繁衍生境具有重要意义。Abstract: The Xijiang Oxbow located in the Anqing section of Yangtze River is the only ex-situ conservation area for the Yangtze finless porpoise (Neophocaena asiaeorientalis). In order to understand the plant community structure in riparian zone of the Xijiang Oxbow and the habitat of the Yangtze finless porpoise in this area, the vegetation in 10 transects of the Xijiang Oxbow was investigated in the summer, 2017. This study identified 166 species of vascular plants with 50 families and 131 genera including 1 family with 1 genus and 1 species of algae, and, 1 family with 1 genus and 2 species of ferns, as well as 163 species of 129 genus belonging to 48 families of seed plants. The main families were the Papilionaceae, Compositae and Gramineae, and the distribution types of families and genera were relatively rich. Besides, plant community structure showed that Shannon-Wiener indexes were between 0.213—0.899 with a mean of 0.629±0.399, and Simpson indexes were between 0.135—0.465 with a mean of 0.315±0.204. The richness of species ranged from 3 to 14 with the same trend as the diversity indexes. The vegetation distribution in riparian zone of the Xijiang Oxbow presents a significant spatial feature. The areas destroyed by human activities on both sides of the river have lower diversity compared to the natural area covered by plant that has higher community diversity and richness. In general, the riparian zone of the Xijiang Oxbow has rich vegetation and high coverage to improve water quality and provide a good spawning and feeding ground for small settled fish, which own great significance to maintain the habitat and breeding for the migratory population of the Yangtze finless porpoise.