为解析苔藓在藏东南森林生态系统中的重要生态作用, 以及森林干扰对林内地面生苔藓的影响, 该研究以藏东南色季拉山地面生苔藓植物为调查对象, 选取林分、坡向、坡度和地势组成等相似的7块100 m × 100 m的样地, 每块样地以林窗为中心, 在其东、南、西、北4个方向选取林窗、林缘和林下3种不同生境设置50 cm × 50 cm的样方, 每块样地共12个样方, 共计168个样方。通过对每个样方进行苔藓植物调查采集, 研究了西藏色季拉山苔藓多样性和不同生境条件下地面生苔藓单位面积生物量特征。主要结果: (1)研究区共有苔藓植物24科63属110种。其中, 优势科有8个, 分别是丛藓科、曲尾藓科、金发藓科、提灯藓科、真藓科、紫萼藓科、青藓科和灰藓科。苔藓各科分布规律明显, 曲尾藓科和真藓科广泛分布于各个海拔, 金发藓科、真藓科和提灯藓科分布在海拔3 700-4 300 m, 而丛藓科多分布在4 300 m以上。(2)林窗生境较林缘和林下复杂, 它干扰了苔藓物种组成和群落结构, 其苔藓种类最多、结构最复杂, 而林下的苔藓种类最少, 群落结构最简单。林窗地面生苔藓生物量最高, 其次为林缘, 林下苔藓生物量最低。(3)地面生苔藓生物量大小不仅受其物种组成、盖度、体形和群落结构的影响, 而且是众多因子共同作用的结果, 而非某一因子起主导作用。

Aims In order to explore the important ecological function of moss in forest ecosystems in the southeast Xizang and provide a theoretical basis for the influence of forest disturbance on forest surface vegetation, the diversity and biomass characteristics of ground moss per unit area in different habitats in the Sygera Mountain of southeast Xizang.

Methods We collected the surface moss in the Sygera Mountain of the southeast Xizang as the investigation object, and selected 7 sample plots with similar forest stand, slope direction, slope and terrain composition, with each plot size of 100 m × 100 m. We took canopy gap of each sample plot as the center, and three different habitats (canopy gap, forest edge and understory) were selected in four directions to set 50 cm × 50 cm quadrats, with 12 quadrats for each sample plot and 168 quadrats in total. Moss survey and collection were carried out in each quadrat.

Important findings (1) 24 families, 63 genera and 110 species of moss were found in the study area, in which there were 8 dominant families, which were Pottiaceae, Dicranaceae, Polytrichaceae, Mniaceae, Bryaceae, Grimmiaceae, Brachytheciaceae and Hypnaceae. There were obvious distribution rules of different moss families, such as Dicranaceae and Bryaceae were widely distributed at all elevations, and Polytrichaceae, Bryaceae and Mniaceae were distributed at altitudes from 3 700 to 4 300 m. Most of Pottiaceae were distributed over 4 300 m. (2) The habitat of canopy gap was more complex than those of forest edge and understory and it interfered with moss composition and community structure, in which the moss community had the most species and the most complex structure. However, the moss community in understory had the least species and the simplest structure. The biomass of ground moss was the highest in the gap, followed by the edge and the lowest in the understory. (3) The biomass of ground moss was not only affected by species composition, coverage, body shape and community structure, but also resulted from the interaction of many factors rather than any one single factor.