摘要:水文节律是河岸带植物群落演替的主要驱动因子，三峡库区"冬蓄夏泄"的水位调度方式不利于原河岸带陆地植物群落的生存。为揭示三峡库区消落带植被在经历长期水位变动后的物种多样性特征及其分布的时空格局，研究以2008年消落带典型区域固定样地野外调查资料为依托，于2016年9月对经历长期水位涨落周年后的消落带植被的自然分布特征与群落物种多样性等进行复位调查研究，运用重要值、多样性指数、LSD检验等统计计算方法针对物种组成、群落多样性及生活型进行了深入探讨。结果表明：区域植被类型以一年生和多年生的草本植物为主，共发现和确认草本植被群落共有22科40属49种，其中禾本科（Gramineae）6种6属、菊科（Compositae）9种9属、蓼科（Polygonaceae）3种1属、大戟科（Euphorbiaceae）6种5属，为主要优势科，单种、属现象明显；消落带植被的物种多样性随海拔变化呈现"单峰"分布格局，中等海拔（155-165 m）的植物物种多样性最高；且海拔与物种多样性指数（Shannon-weiner指数、Pelou指数、Simpson指数和Richness指数）之间的趋势模拟均呈幂指数关系，其拟合系数r值分别为0.834、0.824、0.817和0.808；受环境资源结构决定，不同海拔消落带物种均呈现出特定的R生存对策。此区段消落带共发现9种生活型，且随海拔的增加，一年生草本植物均占据极大的优势地位，但是库区植物的生活型更加多样化，其他生活型，如藤本、灌木以及落叶乔木的物种出现且数量表现为逐渐增多。这些研究结果对未来消落带物种多样性提高及地域性特色的消落带植被维护具有重要的参考价值。



Abstract:Hydrological rhythm is a main driver for the succession of riparian plant communities in fluctuating zones, and the water level regulation of "winter storage and summer discharge" in the Three Gorges Reservoir area is not conducive to the survival of the terrestrial plant communities in the original riparian zone. To reveal the spatial and temporal patterns of the species diversity and distribution of vegetation in the fluctuation zone of the Three Gorges Reservoir after long-term fluctuation in water levels, we conducted a resetting investigation on the natural distribution and species diversity of vegetation in the fluctuation zone in September 2016, based on field survey data from the typical regional fixed plots in the fluctuating zone set in 2008. Statistical methods, such as importance value, diversity index, and LSD test, were used to thoroughly discuss the species composition, community diversity, and life form. The results showed that the regional vegetation type was dominated by annual and perennial herbaceous plants, and a total of 49 species of herbs, belonging to 22 families and 40 genera, were found and identified. The dominant families were Gramineae with six genera and six species, Asteraceae with nine genera and nine species, Polygonaceae with three genera and one species, and Euphorbiaceae with six species in five genera. The floristic characteristics were of single species and genera. Along with the altitude, the species diversity presented a "single peak" distribution pattern, and plant species diversity in the fluctuation zone was the highest at the middle altitude (155-165 m). The trend simulation between the altitude and the dominant species diversity index (Shannon-weiner index、pielou index、simpson index and richness index)showed a power exponential relationship, with fitted coefficients of 0.834, 0.824, 0.817, and 0.808, respectively. Depending on the structure of the environmental resources, the species showed a specific R survival strategy at different altitudes. In addition, nine types of life forms were found in this zone. With an increase in altitude, annual herbaceous plants occupied a great dominant position, but the life type of the plants in the reservoir became more diverse. The species of other plant living types, such as vines, shrubs, and deciduous trees, are gradually increasing. These findings would be of great reference value to the future improvement of species diversity and maintenance of vegetation in the fluctuating zone.





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