采用“空间代替时间”的方法,对处于不同演替阶段的东方水韭(Isoëtes orientalis H. Liu et Q. F. Wang)群落进行了物种组成、群落生态学数量特征、物种多样性及繁殖方式的比较分析,结果表明,在演替初期,群落的多样性(物种丰富度、Shannon - Wiener 指数、Pielou 均匀度指数和 β 多样性指数)最低,群落中东方水韭的多度、盖度、重要值和生态位宽度均最大,是明显的优势种;演替中期,东方水韭的多度、盖度、重要值和生态位宽度降低,但群落的物种多样性最高,是东方水韭的顶极群落;演替后期,群落中东方水韭的多度、盖度、重要值和生态位宽度均最低,多年生草本植物细叶芒(Miscanthus sinensis Anderss.)和菰〔Zizania latifolia ( Griseb.) Turcz. ex Stapf〕等逐渐占据重要地位。 随群落的演替,群落中营无性/ 营养繁殖方式的物种数量逐渐增加,群落的繁殖策略由有性繁殖为主转为以无性/ 营养繁殖为主。 研究结果显示,在东方水韭群落演替过程中,群落物种组成的改变、物种多样性的提高、物种繁殖策略的变化以及生境中生化,可能是导致东方水韭种群衰退的主要原因。

 

Comparative analyses of species composition, community ecological quantitative characteristics, species diversity and propogation mode of Isoëtes orientalis H. Liu et Q. F. Wang communities at different succession stages were conducted by the method of space-replacing-time. The results show that at early succession stage, the community has the lowest diversity ( species richness, Shannon-Wiener index, Pielou evenness index and β diversity index), and the abundance, coverage, important value and niche breadth of I. orientalis population are the highest, which makes I. orientalis the dominant species. At middle succession stage, the abundance, coverage, important value and niche breadth of I. orientalis population all decrease, while the community shows the highest species diversity, which makes the climax community of I. orientalis. At late succession stage, the abundance, coverage, important value and niche breadth of I. orientalis population fall to the lowest levels, and perennial herbs such as Miscanthus sinensis Anderss. and Zizania latifolia ( Griseb.) Turcz. ex Stapf become dominant species. Along with the succession process, the number of species adopting asexual / vegetative propogation increases and the main propogation strategy of the community changes from sexual propogation to asexual / vegetative propogation. It is suggested that in the process of succession, the changes of species composition, species diversity, propogation strategy of species and mesophytic habitat may be the major reason to decline of I. orientalis population.