中文摘要：

苔藓物种多样性变化对苔藓植物保护和森林生态系统健康起着重要的预警作用。基于1977-1980年和2010-2011年对西天目山国家自然保护区苔藓植物的两次详细调查,本文比较了该地区1977-2011年间苔藓植物物种多样性的变化。结果表明：（1）在过去的30年间,该地区苔藓植物的科、属、种数均呈下降趋势,苔类植物的属、种数减少尤为显著;（2）青藓科、曲尾藓科、灰藓科和丛藓科一直为该地区的优势科;（3）科的稳定性均高于属、种;（4）缓冲区的总物种数变化最大,新增物种数最多;核心区（进山门-老殿）苔藓植物种类始终最为丰富,两个时期的物种相似性最高,且苔类占新增物种数百分比最高;核心区（老殿-仙人顶）苔藓物种数最少,相似性最低;（5）核心区的物种多样性要高于缓冲区,是该地区保护苔藓植物多样性的关键区域。

英文摘要：

Bryophyte diversity plays an important role in forest ecosystems and is important in conservation. Based on two surveys of the bryophyte flora in West Tianmu Mountain, Zhejiang Province, China, conducted between 1977 and 1980, and 2010 and 2011, respectively, an analysis was made of changes in bryophte di- versity from 1977 to 2011. We found that： （1） in the past three decades, the number of species, genera and families of bryophytes, especially of liverworts, has tended to decline; （2） Brachytheciaceae, Dicranaceae, Hypanceae and Pottiaceae remain as the dominant families; （3） the stability of families is higher than that of genera and species; and （4） the greatest changes have occurred in the buffer zone, where the number of spe- cies new to the nature reserve is the highest. Most bryophytes are distributed in the area around the entrance to the Old Openning Temple in the core zone. This area shows the highest Sorensen similarity and proportion of new liverwort species. In contrast, from the Old Openning Temple to Xianren Peak in the core zone, only a few species occur and the community exhibits the lowest Sorensen similarity. We suggest that the core zone should be regarded as a key area for bryophyte protection in the region.