封山育林对植物群落结构及多样性的影响

本文研究了四种不同封山类型林地内森林植物群落的组成、结构及多样性的变化,并对多样性在表达植物群落的种类组成和空间结构的复杂程度的应用方面进行了探讨。提出了以Shannen-Wiener多样性指数为基础的植物群落垂直结构多样性指数和盖度加权叶层多样性指数、作为森林植物群落垂直结构复杂性的测度。结果表明,封山育林早期可以使得林内植物个体数和种类数大幅度增加,随着封山时间的延长,科的组成变化较大,科、种多样性指数显著增加。同时,植物群落的空间结构亦发生明显变化,封山林区植物群落的垂直结构和层次性的复杂程度明显高于未封山林区。

Influence of the Closed Forest on Plant Communitv Structure and Diversity

In this paper, the composition, structure and diversity of plant communities in four Chinese pine secondary forests were studied, in which the hillside were closed to facilitate afforestation with different closed time or unclosed. And it is approached to apply diversity to express the complicated degree of the species composition and the spatial structure of plant community. The Vertical Structure Diversity Index and Cover Weighted Foliage Height Diversity Index based on the Shannon-Wiener Diversity Index were used to measure the complicated degree of the vertical structure of the plant community. The results show that closed forest encourages growth of an increased number of plant species and individuals in their early stages. With time, the composition of the families in the closed forest considerably changes, and the family-species diversity obviously increases. The spatial structure of the plant community changes considerably, too. The complicated degree of the vertical structure and the layers in closed forest stands are obviously higher than that in unclosed forest stands.