中文摘要：

为评估在人工林早期发育过程中地表苔藓层片物种组成和结构的演变趋势,选择四川省金川县507林场4-30年林龄的5块云杉（Picea asperata）人工林和1块300年岷江冷杉（Abies faxoniana）原始林,开展了地表苔藓植物调查。采用方差分析法（ANOVA）对苔藓植物特征参数进行差异性检验,采用S？rensen群落相似性系数比较了苔藓群落β多样性差异。结果表明：（1）云杉人工林较原始林地表苔藓物种丰富度高。年轻的人工林（〈16年）较中龄林（21-30年）地表有更多的苔藓种类;（2）原始林较人工林有更高的地表苔藓植物盖度、密度、平均高度和厚度,而不同林龄的人工林之间在苔藓植物层片盖度和密度上并没有表现出统计学意义上的差异（P〉0.05）,但地表苔藓优势种及次优势种组成具有较明显的差异;（3）人工林与原始林地表苔藓共有种具有明显的喜光耐旱特性,4年生未成林地段与原始林共有种数最多,为19种;（4）原始林下地表24种苔藓植物中,除Rhytidium rugosum外,23种在云杉人工林早期发育过程中存在。在人工林发育过程中地表苔藓物种替代明显,替代率随林龄呈增加趋势（0.24-0.60）,有明显的物种替代现象发生。综合分析表明：（1）本文所研究的4-30年的云杉人工林发育过程中地表苔藓结构与多样性并没有表现出预期的恢复趋势,大多数土著苔藓种群还未能有效恢复;（2）要恢复重建林地后演替阶段的苔藓种群结构和多样性,不仅需要在采伐和造林过程中减少对土壤的扰动以保护地表微生境,还应在云杉人工林处于16-20年林龄,地表苔藓植物丰富度发生显著衰退时进行合理疏伐。

英文摘要：

To reveal shifts in composition and structure of bryophyte communities in plantation forests at different stages of early development, we sampled five different aged spruce （Picea asperata） plantations with similar topographic situation and one primary Minjiang fir （Abies faxoniana） forest as a control. We investigated species composition and synusia structure. ANOVA was used to test for differences in characteristic parameters among bryophyte communities, and Sorensen similarity coefficients were used to measure variation in β diversity. Plantations had higher bryophyte species richness than the primary forest, and the young plantation （〈16 years） had more bryophyte species than the middle-aged ones （21-30 years）. Coverage, density, and average height and thickness of bryophytes were greater in the primary forest than in the plantations, While bryophyte coverage and density statistically showed no significant difference （P〉0.05） among plantations, but the composition of dominant and subdominant species differed. Common species in both primary and plantation forests included photophilic and drought-tolerant species, and the 4-year old plantation and primary forest shared the highest number of common species （19 species）. Twenty-four bryophyte species dwelling in primary forest, except Rhytidium rugosum, were shared among the primary forest and plantations, and species turnover rate （0.24-0.60） was increasing with stand age, indicating that species replacement occurred. Our results suggested that ground disturbance during clear cutting and reforestation should be reduced in order to restoration of species in later successional stage. In addition, suitable thinning application in the 16-20-year-old plantations may be useful when the bryophyte species richness begin to decline.