中文摘要：

以广西横县国有镇龙林场马尾松2年生、11年生、13年生、16年生、24年生和50年生人工林替代其演替进程，对马尾松人工林生物多样性变化趋势进行研究，结果表明，（1）马尾松人工林演替进程中物种数量的变化是伴随着阳性先锋物种的衰退和中生性顶级植物的发展，物种数量在演替前期（2～16年）迅速增加，在16年生林分达到高峰，随后（16～50年）逐步降低。（2）在乔木层，马尾松纯林首先演替为针叶落叶阔叶混交林，再演替为针叶常绿阔叶混交林；林下灌草层首先被阳性植物占据，其后逐步被常绿植物替代；在50年生马尾松林，藤本植物物种数明显增高。（3）乔木层物种多样性指数和均匀度指数随林龄的增大呈升高的趋势；而优势度指数先升高（2～13年）后降低（13～50年）。灌木层物种多样性指数在演替前期逐渐升高，到16年生马尾松林达到高峰，而后逐渐下降；优势度指数在幼龄林最高，随后逐渐降低，并趋于稳定；均匀度指数则随着演替进程呈升高的趋势。（4）草本层各项指数变化规律都不明显。本研究为马尾松人工林演替进程生态功能量化研究提供科学依据。

英文摘要：

Taking Pinus massoniana plantations of 6 different ages namely 2, 11, 13, 16, 24 and 50 years old in Zhenlong state-owned forest farm of Guangxi province as study materials, the regular and trend of change of plant biodiversity during the course of vegetation succession were studied. The results were as follows ： 1 ） The change of species was characterized by decline of heliophilous pioneer species and mesophyte, the species number increased quickly from the 2 to 16 years after planting, peak value emerged in 16 year, after that the species diversity de- creased gradually. 2） In the tree layer, the pure Pinus massoniana changed to the mixture with deciduous broad- leaved species, and then changed to the mixture with ever-green broadleaved species. The shrub layer was firstly substituted by heliophilous plants, then gradually replaced by evergreen plant species. Up to the age of 50 years, the species number of lianas increased dramatically. 3 ） As far as the tree layer was concerned, the diversity index and evenness index showed the tendency of increase as the succession process going on, the dominance index in- creases before 13 years and then decreased. As far as shrub layer is concerned, the diversity index gradually in- creased and obtained the peak value at 16 years and gradually decreased after that. The dominance index in sapling stage was the highest, and then gradually decrease, and tended to be stable, while the evenness index showed the tendency of increase. 4） The change of herbaceous layer at different succession stage was not obvious.