海南岛热带天然针叶林附生维管植物多样性和分布

作为热带林中一个重要的特征性组分, 附生维管植物对于维持热带森林的物种多样性及其生态系统功能均具有重要作用。该文首次系统地报道了热带天然针叶林中的附生维管植物多样性和分布特征。以海南岛霸王岭国家级自然保护区保存完好的热带天然针叶林(我国唯一较大面积分布的南亚松(Pinus latteri)天然林)中的附生维管植物为研究对象, 通过样带调查(共设置12个10 m × 50 m的样带, 记录每个样带内胸径(DBH) ≥ 5 cm树木上附生维管植物的物种名称、株数及附生高度), 分析附生维管植物的物种多样性和空间分布特征。结果表明: 1)热带针叶林0.6 hm ²面积内共有附生维管植物769株, 分属于7科17属27种, 附生兰科植物和萝摩科植物为优势类群; 2)附生维管植物在水平方向上呈现出聚集分布; 3)附生维管植物在垂直方向上, 在中等高度层次(10-20 m)分布最多, 在下层(0-5 m)也有较多的分布; 4)少数附生维管植物对南亚松表现出一定的选择性, 如华南马尾杉(Phlegmariurus fordii)、玫瑰毛兰(Eria rosea)、眼树莲(Dischidia chinensis)和铁草鞋(Hoya pottsii)等; 5)附生维管植物的物种丰富度及多度与宿主胸径均存在显著的正相关关系。

Diversity and distribution of vascular epiphytes in the tropical natural coniferous forest of Hainan Island,China

Aims As one of the most distinctive components of tropical forests, vascular epiphytes play vital roles in maintaining biodiversity and ecosystem functioning. The diversity and distribution of vascular epiphytes in tropical natural coniferous forest are reported systematically for the first time in this study. Our objective was to explore species richness, abundance, distribution patterns, and relationship between vascular epiphytes and host trees in the only Pinus latteri natural forest with large area in China. Methods Twelve plots of 10 m × 50 m were established in the tropical natural coniferous forest in Bawangling National Nature Reserve, Hainan Island, China. We recorded species, individuals and height of attachment of vascular epiphytes on each tree ≥ 5 cm diameter at breast height (DBH). Based on two datasets (individuals in each subplot of 10 m × 10 m and on each host tree), the horizontal distribution pattern of vascular epiphytes was analyzed using Kolmogorov-Smirnov test and Variance-to-mean Ratio. Based on species and individuals at 5 m intervals from the forest bottom to the top, the vertical structure of vascular epiphyte assemblages was analyzed. The relationship between vascular epiphytes and host tree size was assessed using Spearman correlation. Important findings We recorded 769 individual vascular epiphytes belonging to 27 species, 17 genera and 7 families in the total sample 0.6 hm². The Orchidaceae and Asclepiadaceae were dominant. The vascular epiphytes were clumped horizontally. Vertically, 49.3% were at intermediate heights (10–20 m) and 19.0% at 0–5 m, but only 7.2% were at >25 m. Most vascular epiphytes showed no preference for host trees, but a few species, e.g., Phlegmariurus fordii, Eria rosea, Dischidia chinensis and Hoya pottsii had higher occurrence rates on the host tree of Pinus latteri. Vascular epiphyte abundance and species richness were both significantly positively correlated with host tree size.