宝天曼自然保护区栎类林群落不同火烧演替序列物种多样性特征

Species Diversity Characteristics of Quercus spp. Community of Different Series Stage After Fire in Baotianman National Nature Reserve in Neixiang County

采用空间序列代替时间序列的方法,研究不同恢复阶段栎类群落物种多样性对地表火扰动的响应。结果表明: 宝天曼自然保护区栎类群落物种多样性丰富,不同恢复阶段栎类群落 Shannon-Wiener 指数和 Simpson 指数均表现出先升高后降低的特点; 乔木层 Pielou 均匀度指数变化不大,灌木层和幼苗层 Pielou 指数先增加后降低,但草本层 Pielou 均匀度指数波动较大,表现为先高后低再升高然后降低的特点,说明林火扰动对栎类群落林下草本层产生了重要影响; 栎类群落乔木层、灌木层、幼苗层和草本层之间物种多样性的差异大多不显著,只有乔木层和草本层以及草本层和幼苗层之间的 Pielou 均匀度指数有显著差异,乔木层和灌木层的 Pielou 均匀度指数有极显著差异。不同恢复阶段的物种多样性特征,草本层物种多样性差异不显著,其他各层物种多样性特征变化不具规律性; 栎类群落林下灌木和草本层在过火后 10 年物种变化更替频繁,但不同恢复阶段栎类群落幼苗始终占据一定优势; 随着植被恢复的进程,灌草植被的变化是耐荫种逐步替代阳生种的过程。

In this study, we used a space series in place of time series approach to investigate species diversity of fire chronosequence（ 1-, 5-, 10-, 15-year） in Quercus spp. community in Baotianman National Nature Reserve, a warm- temperate area, north China. The results indicated that the plant species diversity of these communities was high. At different series stage after fire, the Shannon-Wiener and Simpson indexes increased at early stage and then declined. Meanwhile, the Pielou index of tree layer did not signicantly changes, but that of shrub and seedling layer increased at first and then declined, and that of grass layer showed a higher- lower- higher fluctuation. There was no significant difference of diversity indexes among all layers, except the Pielou index which was significantly different between tree and grass layer or grass and seedling layer, and extremely significantly different between tree and shrub layer. The species of shrub and grass layer changed much in 10 years after fire, but the seedling maintained prevalence at different series stage. In the shrub and grass species, heliophyte species mainly emerged in early stage while cheliophytes ones, mainly in late stage.