綠島山地植群組成與環境因子之研究

Mountane Vegetation Composition and Environmental Factors of Lutao

謝光普(Gaung-Pu Hsieh) ； 楊勝任(Sheng-Zehn Yang) ； 葉富雅(Fu-Ya Yeh)

《中華林學季刊》 42卷4期 (2009/12) Pp. 481-501

https://doi.org/10.30064/QJCF.200912.0002

摘要

綠島位於台灣東南方外海，面積約15.09平方公里，本研究旨在建立綠島完整植物清單，並調查主要環境變數說明綠島山地植物群落分布。本文共調查34個250平方公尺植群樣區並評估12項可能影響的環境因子。使用雙向指標種分析及降趨對應分析進行植群分類，典型對應分析找出主要的環境梯度軸以及顯著的環境因子，以了解植群分布序列。本文使用Krober指數在屬與種層級探討綠島植相與蘭嶼，恒春半島及臺灣的相似性。結果顯示綠島目前有132科364屬492種原生維管束植物，歸化植物有26科56屬59種，約占10.7%。物種數最多的前3科為禾本科42種、菊科30種、茜草科26種。綠島風藤為綠島唯一的固有種。綠島與蘭嶼植相的Krober相似性指數均最高，顯示兩區域有密切關係。綠島山地植群區分為3個林型：蘭嶼新木薑子－樹杞林型；貝木－鵝掌柴林型；紅頭咬人狗－大葉樹蘭林型。典型對應分析結果顯示與主要梯度軸有顯著相關的海拔、陽離子交換容量和坡度等環境因子，影響本區植相與植物社會分布。

關鍵字

典型對應分析 ； 植相組成 ； 次生林 ； 植群型

並列摘要

Lutao (Green Island) has an area of 15.09km^2 off the southeast coast of Taiwan. The aims of this study were to establish complete plants checklist on Lutao and to explore the environmental variables that determine the spatial distribution of montane communities. Thirty-four quadrats of 250 m^2 were sampled from montane areas of the island and twelve environmental factors were recorded for each quadrat. Classiication of vegetation was based on two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA), while canonical correspondence analysis (CCA) was used to identify environmental gradients and to extract the significant environmental factors linked to vegetation distribution. The similarities among Lutao, Botel Tobago, Hengchun Pennisula and Taiwan was used Krober similarity index according to the genera or species taxa. Four hundred and ninety two native species, including 364 genera and 132 families, were recorded from this study. Fifty nine species occupied 10.7% of 492 species, belonging to 26 families were naturalized. The major families with higher species richness were Gramineae (42 species), Compositae (30 species) and Rubiaceae (26 species) respectively. Only one of the recorded species, Piper kwashotensis Hayata, is endemic. The Krober similarity values between Lutao and Botel Togbago are the highest, indicating that these two areas were more relative than others. The vegetations were classified into three vegetation types: Neolitsea villosa-Ardisia sieboldii type, Timonius arboreus-Schefflera octophylla type, Dendrocnide kotoensis-Aglaia ellipticfolia type. The main gradient, identified by CCA, were altitude, cation exchange capacity and slope, those were the important variables explaining the floristic variation and vegetation distribution.

並列關鍵字

Canonical Correspondence Analysis ； Floristic composition ； Secondary forest ； Vegetation types