浙江东白山次生针阔混交林群落组成及结构动态

Community composition and structure dynamics of secondary coniferous and broad-leaved mixed forest in Dongbaishan,Zhejiang Province

次生针阔混交林是亚热带地区常见的森林类型,研究次生针阔混交林群落的演替特征及其更新规律,将为本地区植被恢复及森林经营管理提供重要依据。该文基于2013和2018年两次调查东白山次生针阔混交林1 hm^(2)固定样地的数据,从木本植物组成、群落物种多样性、物种重要值、径级结构等方面,分析了东白山次生针阔混交林群落组成和结构的动态变化。结果表明:(1)2013—2018年间,群落内物种数和植株数均显著下降(P<0.05);(2)样地内DBH≥1 cm的个体死亡1505株,年均死亡率6.40%,新增个体71株,年均补员率0.35%;(3)群落物种多样性指数均显著下降(P<0.05),其中Margalef丰富度指数下降最多,降低了25.03%,Shannon-Wiener指数降低了11.88%;(4)林冠层中常绿阔叶树种的优势地位在进一步加强,而针叶树种的优势度在逐渐下降;(5)5 a间,大、中径级的个体比例逐渐增加,小径级植株的存活个体比例逐渐下降。该研究表明,2013—2018年间,东白山次生针阔混交林群落组成和结构总体发生了较为显著的动态变化,群落处于次生针阔混交林向常绿阔叶林快速演替阶段。

Secondary coniferous and broad-leaved mixed forest is very common in subtropical regions.Studying the community succession characteristics and regeneration rules of the secondary coniferous and broad-leaved mixed forest will provide a scientific basis for vegetation restoration and forest management in this area.Using two datasets(2013 and 2018)from a permanent 1 hm^(2) secondary coniferous and broad-leaved mixed forest plot in Dongbaishan(DBS),we analyzed the community composition and structure dynamics of tree species composition,community species diversity,species importance values,and size class structure and so on.The results were as follows:(1)Species richness and individual numbers were significantly reduced in the community during 2013-2018(P<0.05);(2)In the plot,1505 individuals DBH≥1 cm died,with an annual average mortality of 6.40%,and 71 new individuals recruited,with an annual average recruitment rate of 0.35%;(3)The community species diversity indexes declined significantly(P<0.05),of which Margalef richness index changed greatly,decreased by 25.03%,and Shannon-Wiener index decreased by 11.88%;(4)The dominant position of evergreen broad-leaved tree species were strengthening,while coniferous tree species were gradually reduced;(5)During the five years,the proportion of large and medium size class plants gradually increased,while the proportion of small size class plants gradually decreased.In general,the community composition and structure dynamics of the secondary coniferous and broad-leaved mixed forest community in DBS changed significantly during 2013-2018.The community is in a rapid succession stage from secondary coniferous and broad-leaved mixed forest to evergreen broad-leaved forest.