CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan Province, 650223, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Am J Bot. 2020 May;107(5):761-772. doi: 10.1002/ajb2.1474.
The distribution and performance of bryophyte species vary with vertical gradients, as a result of changes in environmental factors, especially light. However, the morphological and physiological drivers of bryophyte distribution along forest vertical gradients are poorly understood.
For 18 species of mosses and liverworts distributed among three vertical microhabitats (ground, tree trunk, and branch, variance in 28 morphological and photosynthetic functional traits was comparatively analyzed among the microhabitats and bryophyte life-forms in a subtropical cloud forest in Ailao Mountain, Yunnan, southwestern China. Principal component analysis (PCA) was used to summarize trait differences among bryophyte species.
In contrast to trunk and ground dwellers, branch dwellers tended to reduce light interception (smaller leaf and cell sizes, lower chlorophyll content), protect against damage from intense irradiation (higher ratios of carotenoids to chlorophyll), raise light energy use (higher photosynthetic capacity), and cope with lower environmental moisture (pendant life-forms, thicker cell walls). The PCA showed that ecological strategies of bryophytes in response to levels of irradiation were specialized in branch dwellers, although those of ground and trunk dwellers were less distinct.
Environmental filtering shaped the combination of functional traits and the spatial distribution of bryophytes along the vertical gradients. Bryophyte species from the upper canopy of cloud forests show narrow variation in functional traits in high-light intensity, whereas species in the lower vertical strata associated with low-light intensity used contrasting, but more diverse ecological strategies.
由于环境因素（尤其是光照）的变化，苔藓植物物种的分布和表现随垂直梯度而变化。然而，苔藓植物沿森林垂直梯度分布的形态和生理驱动因素仍知之甚少。
在中国西南部哀牢山亚热带云雾林中，比较了三种垂直小生境（地面、树干和树枝）中分布的 18 种藓类和苔类的 28 种形态和光合功能特征的变异，分析了小生境和苔藓植物生活型之间的差异。主成分分析（PCA）用于总结苔藓植物物种之间的特征差异。
与树干和地面生物相比，树枝生物往往减少光捕获（叶片和细胞较小，叶绿素含量较低），防止强辐射造成的损害（类胡萝卜素与叶绿素的比例较高），提高光能利用（较高的光合能力），并应对较低的环境湿度（悬挂生活型，细胞壁较厚）。PCA 表明，苔藓植物对辐射水平的生态策略在树枝生物中是专门化的，而地面和树干生物的生态策略则不那么明显。
环境过滤塑造了功能特征的组合以及苔藓植物沿垂直梯度的空间分布。云雾林上层树冠中的苔藓物种在高光强下表现出功能特征的狭窄变化，而与低光强度相关的较低垂直层中的物种则使用不同但更多样化的生态策略。
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