亚高山针叶林人工恢复过程中物种多样性变化

通过样方调查，以空间代替时间的方法，对亚高山人工针叶林恢复过程中，乔木、灌木和草本层物种多样性的变化进行了研究，探讨了不同恢复阶段各层物种的相关系数．结果表明，亚高山人工针叶林恢复过程中物种的丰富度、多样性和均匀性都在波动中逐渐增加，云杉人工林恢复过程中总体上是朝着有利于物种多样性恢复的方向发展．在人工林恢复序列中群落乔木物种的平均相关系数为41．88％。灌木为50．61％，草本为37．22％，说明在70年的人工林恢复过程中，灌木种类具有较高的连续性和稳定性；草本植物则随着人工林环境条件的改变而出现较大的消亡和更新，显示出较大的波动性．乔木层物种的稳定性和连续性介于灌木和草本植物之间．

Dynamics of species diversity in artificial restoration process of subalpine coniferous forest

Through plot investigation and by adopting the concept of space as a substitute for time, the developments of species diversity of trees, shrubs and herbaceous plants in subalpine coniferous plantations at different restoration stages were studied, and the correlation coefficients of species in each layer were discussed. The results indicated that in the restoration process, the species richness, diversity and evenness in subalpine coniferous plantations were gradually increased in a fluctuating way. The restoration process of Picea asperata plantations showed a tendency of development that in favor of resuming species diversity. The indices of species richness (species number and Margalef index) and species diversity (Shannon-Wiener index and Simpson index) of trees increased rapidly from the early stages of plantation establishment to the stage of canopy closing (about 30 yr of stand age) and then presented a tendency of decrease with some slight fluctuations, while the index of species evenness showed a periodical rising trend. For the shrub layer, the indices of species richness (Simpson index and Macintosh index) gradually increased with increasing restoration years, whereas the indices of species diversity (Shannon-Wiener index) decreased in the early stages, sharply increased during the stages of canopy closing, and then slowly decreased, which exhibited a tendency of high-->low-->high. In the layer of herbaceous plants, the indices of species richness (Margalef index and number of species) and species diversity (Simpson index, Macintosh index and Shannon-Wiener index) presented a trend of decrease in the early stages of plantations establishment to canopy closing and increased later on. During this process, herbaceous species and their life forms changed greatly, with shade tolerant species gradually substituting the intolerant species. Among the plantations of different stand ages, the average correlation coefficients of trees, shrubs and herbaceous species were 41.88%, 50.61% and 37.22%, respectively, indicating that in the 70 years of artificial forest restoration, the continuity and stability of shrub species were the highest, those of herbaceous species showed greatest fluctuation because of the disappearance and regeneration occurred with the alteration of the environmental conditions of plantations, and those of the trees were intermediary.