Abstract

Floristic composition and structure of a lowland secondary forest was studied in detail on Mt. Lonlon of northeastern Taiwan.. The study plot contained 241 species, of which 70 were trees, 39 shrubs, 48 climbers, 45 herbs, and 39 pteridophytes. Diversity of the trees with dbh 1.0 cm was calculated as Shannon-Weiner index (3.09), Simpson index (0.08), and Equitability index (0.79). The dominance-diversity curve seemed to conform to a lognormal species distribution. The community structure was characterized by a relative dominance of Myrsine sequinii, Ardisia sieboldii, Persea thunbergii, Wendlandia formosana, Gardenia jasminoides, and Schefflera octophylla in the canopy, and Psychotria rubra and Lasianthus plagiophyllus in the understory. Detrended correspondence analysis and cluster analysis led to the recognition of three ecologically meaningful groupins. Diameter distribution curves for vegetation types were observed to fit the negative exponential function. However, slight under-representation in the smallest size-class of the upper slope vegetation might be indicative of some minor anthropogenic disturbances. Compared to the mature low land rain forests of other areas the Lonlon forest showed a lower basal area, and seemed to be indicative of structural immaturity.

中文摘要

本文在闡述台灣東北角隆龍山次生林之組成及結構。研究區內計包含241種為管束植物，其中數目70種、灌木39種、藤蔓48種、草本類45種、蕨類39種。DBH 樹木之歧異度為：Shannon-Wiener index（3.09），Simpson index（0.08）及Equitability index（0.79）。優勢度─歧異度曲線近似分佈型。植物社會之優勢種在樹冠層為大明橘（Myrsine sequinii）、樹杞（Ardisia sieboldii）、紅楠（Persea thunbergii）及水金京（Wendlandia formosana）；灌木層為九節木（Psychotria rubra）及圓葉雞屎樹（Lasianthus plagiophyllus）。改良型對應分析及群團分析的結果顯示三類植被型。各植被型樹木大小徑及分佈趨近負指數函數，但是在上坡稜脊處最小徑及的密度偏低，反映出人為干擾的跡象。與其他低海拔雨林相比較，隆隆山次生林之總底面積較小，仍屬未成熟之林分。