兩種附生巢蕨在北台灣亞熱帶潮濕森林的空間分布特性

Spatial Patterns of Two Epiphytic Bird's-nest Ferns in a Moist Subtropical Forest, Northern Taiwan

王相華(Hsiang-Hua Wang) ； 蘇聲欣(Sheng-Hsin Su) ； 張勵婉(Li-Wan Chang)

《台灣林業科學》 35卷3期 (2020/09) Pp. 205-216

https://doi.org/10.7075/TJFS.202009_35(3).0002

摘要

附生巢蕨具有特別的生態棲位，也營造出特殊的懸空微棲地環境供樹生的無脊椎動物棲息，與熱帶、亞熱帶陸域生物多樣性和生態系功能密切相關。本研究於「福山森林動態樣區」所位處的北台灣亞熱帶潮濕森林內設置3.84 ha樣區並進行附生巢蕨調查。目的為經由分析台灣山蘇花、山蘇花兩種大型巢蕨的空間分布特性，探討對光照、水分有強烈影響的地形及宿主（樹木）結構因子如何形塑這兩種巢蕨的空間分布，以了解兩種巢蕨對光照、水分的適應性是否有差別。就地形而言，此兩種巢蕨多集中分布在棲地水分較高的下坡、溪溝；就樹木宿主上的附生位置而言，兩種巢蕨多附生在宿主的主幹上，而非樹冠層的枝條上，附生高度集中在離地2～4 m高度，鮮少分布在10 m以上。台灣山蘇花與山蘇花的空間分布特性近似，即便是在鮮少發生乾旱的福山亞熱帶潮濕森林，台灣山蘇花、山蘇花仍然多數分布在環境較為濕潤的地形，以及受光量較低的林冠下層樹木主幹。本文由光合作用、水分生理特性及颱風對森林冠層擾動多個面向角度切入，簡要討論附生巢蕨在此一亞熱帶潮濕森林的空間分布特性。

關鍵字

巢蕨 ； 附生植物 ； 潮濕森林 ； 空間分布 ； 地形 ； 樹木寄主

並列摘要

The aerial micro-habitats created by bird's-nest ferns provide invertebrate habitats that are distinct from the forest-floor environment, and they contribute to the biological diversity of tropical and subtropical forests. In this study, we set up and surveyed a 3.84-ha sample area in the Fushan Forest Dynamics Plot, which is located in a subtropical moist forest in northern Taiwan. We analyzed the spatial distributions of 2 native bird's-nest ferns, Asplenium antiquum and A. nidus, to explore how topography and structural factors of host trees, which strongly affect the light conditions and water availability, shape the spatial distributions of these 2 species. The distributions of these 2 bird's-nest ferns were mostly concentrated in downhill areas and near creeks with higher water availability. In terms of the epiphytic locations on host trees, the 2 bird's-nest ferns were mostly attached to the trunk of host trees rather than to the branches in the canopy. The epiphytic height of both species was concentrated at 2~4 m above the ground, and they rarely grew at a height of ＞10 m above the ground. The spatial distribution characteristics of A. antiquum and A. nidus were similar. Even in the Fushan subtropical humid forest where drought events are rare, A. antiquum and A. nidus were mostly distributed in downhill areas and near creeks with relatively high water availability and on the lower trunks of host trees with low light levels. The roles of photosynthesis, water physiological characteristics, and typhoon disturbances to the forest canopy in affecting the spatial patterns of bird's-nest ferns in this subtropical moist forest are also discussed.

並列關鍵字

bird's-nest fern ； epiphyte ； moist forest ； spatial pattern ； topography ； host tree