臺灣天然林之羣落生態研究（四）蘭嶼植羣與植相之研究

Synecolopical studies on the natural forest of Taiwan(IV) STUDIES ON THE VEGETATION AND FLORA OF LANYU

劉棠瑞 ； 林則桐

《臺灣省立博物館科學年刊》 21卷 (1978/12) Pp. 1-80

https://doi.org/10.6548/ATMA.197812_21.0001

摘要

I、蘭嶼位於臺灣之東南方，為一古老的火山小島，面積雖僅有45平方公里，但植物極為豐富。就氣候條件而言，本島非常接近熱帶雨林氣候區。II、生長於蘭嶼之植物，有許多特殊形相，例如樹體多具支持根，葉形多為全緣，花多幹生，植物多為纏勒性，以及植物組成複雜等。此等特徵，皆與在典型之熱帶雨林所見者相同，因此本島之森林，應屬於熱帶雨林羣系。III、根據實地調查與分析，本島之植物，由7種羣落所組成，即1.海濱植物，2.草本，3.灌叢，4.濕生植物，5.森林，6.放牧草原及7.二次林等是也。IV森林為本島最主要且為最複雜之植羣，根據所調查之60個樣區，利用列表比較法，可將其分為三個羣叢及三個簡叢，如下:(1)黃楊~瓊崖海棠~密脈赤楠~貝木過渡羣叢(2)賽赤楠~蘭嶼福木~貝木~密脈赤楠羣叢(3)白榕~蘭嶼福木羣叢①豬母乳~樹杞~江某簡叢②茄萃~蘭嶼木薑子簡叢③繁花社英~三蕊楠簡叢　各簡章羣與其生育地之環境，如氣候、地形、土壤等，自有極密切的關係，或可能為演替之一階段。V、本文曾討論了乾生及濕生兩種演替序列之可能途徑。蘭嶼的森林植羣，目前似尚未到達極盛相，原因為本地雅美族人，不斷在森林中砍取薪材及建築材料，若無此等人為干擾，其所到達之極盛相，應比目前更具熱帶雨林之特色。VI、蘭嶼之自生管束植物，統計結果，共有160科、535屬、886種，扣除歸化種後，其植物成分屬於臺灣本島者，為78.04%，屬於菲律賓者為58.56%，屬於琉球者為57.38% 。至於共通固有種，臺灣有者，總計46種，菲律賓有者總計29種，琉球有者合計僅有兩種。由以上統計，得知蘭嶼在植物地理學上，應屬於臺灣之植物區系。由於蘭嶼之自生種，未見之於臺灣者，大多數為屬於菲律賓之成分，因此蘭嶼可視為臺灣與菲律賓二植物區系中，植物之交匯所。

並列摘要

1. Lanyu or Botel Tobago is an old volcanic islet situated 91 Km off the southeast coast of Taiwan. It is, however, only with a total area of about 45 square Km in width, it is very rich in plants. Climatically, Lanyu is also a place located near to the area covered with tropical rain forest. 2. On Lanyu, a great deal of plants was carefully observed to have stilt and plank buttress roots, cauliflory, stranglers, and special leaf forms, in addition to the complicated components of forests. All such features clearly show peculiarities of a typical tropical rain forest. 3. Based on our detailed investigation, the vegetation of Lanyu can be divided into seven types of plant communities. They are as follows: (1) Littoral plant community, (2) herbs, (3) shrubs, (4) hygrophytic community, (5) forests, (6) pasturing grassland, and (7) secondary forest. 4. Of the seven communities, the forest community is the most important and complicated one on this islet. According to the analysis of data got from the 60 plots set in the forest, again it can be divided into three assoiations including one associes as follows: (1). Buxus microphylla var. intermedia-Calopliyllum inophyllum-Syzygium densinervium var. insulare-Timonius arboreus associes. (2). Acemena acuminatissima-Garcinia linii-Timonius arboreus-Syzygium densinervium var, insulare association. (3). Ficus benjamia-Garcinia linii association. Because of its different components in species, this association can be classified again as the following three faciations: (I) Ficus fistula-Ardisia sieboldii-Schefflera octophylla faciation. (II) Bischofia javanica-Litsea gariciae faciation. (III) Elaeocarpus multiflorus-Endiandra coriacea Faciation. Each faciation is, of course, closely related to the environmental factors, such as climate, topography, soil, etc. or is possibly a sere of succession. 5. The possible ways of plant succession of hydroseres and xeroseres on this islet have been presumed upon. Concerning the development of forest on Lanyu, still it does not reach the climax now. The reason is that the native people always cut down certain large trees in forest for firewoods, building and ship-construction materials, and the stands are thus destructed and obstructed to reach the climax. If without human being's disturbance, it would have reached the climax and would be with more characteristics of typical tropical rain forest. 6. So far, a total number of 886 species belonging to 535 genera and 160 families of indigenous vascular plants have been recorded on Lanyu. According to statistics of plants except the naturalized ones, the floristic characters of Taiwan found here have a highest percentage (78.04%) and stand first, those of the Philippines, est 58.56%, second in turn, and those of the Ryukyus, 57.38%, in third. The species being coendemic to Taiwan are 46, to the Philippines, 29 and to the Ryukyus, only 2. Based on the statistics mentioned above, floristically Lanyu should be put into the region of Taiwan. Among the native plants, many of them are also found in the Philippines, but not in Taiwan. These Philippine elements suggest that Lanyu is admitted to be an intermingling area of Taiwan and Philippine plants.