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毛竹(Phyllostachys edulis)向邻近次生常绿阔叶林扩张现象明显,极大地影响了常绿阔叶林的生态功能,但关于其扩张对常绿阔叶林的群落结构与生物多样性影响的后效研究较少。本文采用时空替代法,在江西井冈山国家级自然保护区沿毛竹扩张方向,依次设置毛竹林、竹阔混交林和常绿阔叶林样地,比较分析了扩张前后群落物种相似性、群落结构和多样性指数等特征。结果表明:(1)毛竹林与常绿阔叶林乔木层、灌木层和草本层的Bray-Curtis相似性指数很小,分别为0.003、0.046和0.030。(2)毛竹林的垂直结构呈“>”型,高度12–14 m区间的多度百分比达33.3%,径级结构集中分布于5–10 cm区间,达总数的90.0%;常绿阔叶林的垂直结构为“L”型,高度2–4 m的物种数占54.3%,径级分布范围较广,4个较大径级区间的平均百分比为10.3%。(3)乔木层的Shannon-Wiener指数由常绿阔叶林的2.56降至毛竹林的0.06,降幅高达98%;灌木层也由2.58降至2.03,降幅21%。以上结果说明,毛竹扩张会导致次生常绿阔叶林群落组成和结构简化、物种多样性下降,对森林生态系统功能产生负面影响。
The phenomenon of Phyllostachys edulis dilating nearby secondary evergreen broad-leaved forest obviously affected the ecological function of evergreen broad-leaved forest. However, the influence of its expansion on the community structure and biodiversity of evergreen broad-leaved forest After-effect research less. In this paper, the spatial-temporal alternation method was used to set up the bamboo-green bamboo forest, the broad-leaved mixed forest and the evergreen broad-leaved forest along the direction of bamboo expansion in Jinggangshan National Nature Reserve in Jiangxi Province. The similarity, community structure and community structure of the community before and after expansion Diversity index and other characteristics. The results showed that: (1) The Bray-Curtis similarity index of tree layer, shrub layer and herb layer in Phyllostachys pubescens forest and evergreen broad-leaved forest was very small, which were 0.003, 0.046 and 0.030, respectively. (2) The vertical structure of Phyllostachys pubescens stands in the shape of “”>, with the percentage of 33.3% of the height in the range of 12-14 m, and the diameter structure concentrated in the range of 5-10 cm, accounting for 90.0% of the total; The vertical structure of the broad-leaved forest is “L” type, with 54.3% of species 2-4 m in height, with a wider range of diameter distribution and an average percentage of 10.3% of the four larger diameter ranges. (3) The Shannon-Wiener index of arbor layer decreased from 2.56 in evergreen broad-leaved forest to 0.06 in Phyllostachys pubescens with a decrease of 98%; shrub layer decreased from 2.58 to 2.03, a decrease of 21%. The above results show that the expansion of the bamboo will lead to the composition and structure of the secondary evergreen broad-leaved forest to simplify, species diversity decreased, the function of forest ecosystems have a negative impact.