西双版纳热带雨林和热带山地常绿阔叶林附生苔藓的组成与多样性格局

Composition and diversity pattern of epiphytic bryophytes in tropical rainforest and tropical montane evergreen broad-leaved forest in Xishuangbanna

为探讨西双版纳热带雨林和热带山地常绿阔叶林附生苔藓的组成、多样性格局及其维持机制,该文对两种植被的树干附生苔藓植物进行了调查与分析。所选择的样地位于西双版纳勐腊县,每种植被类型选择10个20 m×20 m的样方,每个样方选择约10棵样树。结果表明:(1)本调查共记录到附生苔藓20科39属60种,其中热带雨林附生苔藓有19科33属48种,热带山地常绿阔叶林附生苔藓有9科14属19种,共有种6种。(2)热带雨林最优势科为平藓科,热带山地常绿阔叶林最优势科为锦藓科。(3)热带雨林比热带山地常绿阔叶林具有更高的物种丰富度、β多样性和γ多样性。(4)不同径级和不同树皮粗糙度宿主上附生苔藓植物的盖度差异显著,而物种丰富度差异不显著。(5)苔藓植物的生活型对植被类型有所偏好,表现为悬垂型、扇型、交织型、粗平铺型集聚于热带雨林,丛集型、垫状型、细平铺型集聚于热带山地常绿阔叶林。(6)直接排序结果表明,宿主特性特别是树皮粗糙度显著影响苔藓植物生活型的组成和分布。热带雨林比热带山地常绿阔叶林能提供更多样的微生境,因而孕育了物种更丰富的附生苔藓植物。考虑到不同的植被类型或宿主特性条件下孕育着不同生活型组成的苔藓植物,因此可将苔藓生活型作为今后森林监测的一项重要指标。

This study explored the bole epiphytic bryophytes in the tropical rainforest and the tropical montane evergreen broad-leaved forest in Xishuangbanna,aimed to reveal their composition,diversity patterns,and maintenance mechanisms.The study site is located in Mengla County.Ten sampling plots(20 m×20 m)of each vegetation type were chosen,and about ten tree individuals were sampled in each plot to survey the bole epiphytic bryophytes.The results were as follows:(1)In total,60 species belonging to 39 genera and 20 families were recorded.Among them,48 species belonging to 33 genera and 19 families were recorded in the tropical rainforest,and 19 species belonging to 14 genera and 9 families were recorded in the tropical montane evergreen broad-leaved forest.(2)The dominant family of the tropical rainforest is Neckeraceae,while the dominant family of the tropical montane evergreen broad-leaved forest is Sematophyllaceae.(3)The species richness,βandγdiversities of the tropical rainforest were higher than the tropical montane evergreen broad-leaved forest.(4)The coverage of epiphytic bryophytes was significantly different among different diameter classes and bark roughness.(5)Pendants,fans,wefts,and rough mats prefer the tropical rainforest,while turfs,cushions,smooth mats gather in the tropical montane evergreen broad-leaved forest.(6)The results of redundancy analysis showed that host characteristics,especially bark roughness,significantly affected the composition and distribution of life forms.Tropical rainforest provide a greater diversity of microhabitats than tropical montane evergreen broad-leaved forest,and thus harbor more epiphytic bryophyte species than the latter.Considering different bryophyte life form were recorded in different vegetation types or host characteristics,life forms can be considered as an important indicator for forest monitoring and management.