臺灣天然林之羣落生態研究（三）－恆春半島南仁山區植羣生態與植物區系之研究

Synecological studies on the natural forest of Taiwan(3) Studies on the Vegetation and Flora of Nanjenshan Area on Hengchun Peninsula

劉棠瑞 ； 劉儒淵

《臺灣省立博物館科學年刊》 20卷 (1977/12) Pp. 51-149

https://doi.org/10.6548/ATMA.197712_20.0002

摘要

I、南仁山區位於本省最南端恆春半島之中部，東臨太平洋，西止於港口溪。該區自海濱西向內陸，漸次形成縱橫交錯之低山與丘陵，其間尚散佈少許湖沼與東流入海之小溪流。南仁山區平均海拔約在300公尺，雖地勢不高，但氣候頗富變化性，年平均温度爲25°C，降雨集中在夏季，冬季則頗爲乾燥，並受强烈東北季風之吹襲，年雨量自沿海之1,900mm，向內陸山地增高到3,600mm。土壤以輕粘土爲主，深約及60公分，pH值在5.2至5.9之間。南仁山區因具此環境，故其植羣變化亦大。II、根據實地調查結果，南仁山區之植羣，因植物生長的地位不同，可區分爲1.水生與濕生羣落，2.草本羣落，3.密閉灌叢，4.森林（包括海岸林）及5.海濱植物等五種羣落。各植物羣落除分别設立樣區，以調查硏究其形相、結構與組成外，另探討其與生育地各環境因子之關係，藉以推測該地區植羣演替的情形等。III、山地森林爲本山區最重要之植羣，就氣候條件言，此一植羣係介於熱帶季風雨林與熱帶雨林之間者，因其具有特徵性之支柱根、板根、幹生花及多數着生植物等。經設置37個方形樣區調查，並利用列表比較法分析，可再將其分爲如下五個羣叢，即1.恆春苦櫧〜金斗櫟〜星刺苦櫧羣叢，2.浸水營石櫟〜嶺南青剛櫟羣叢，3.嶺南青剛櫟〜長尾尖葉櫧〜短尾葉石櫟〜青剛櫟羣叢，4.大葉楠〜香楠〜香葉樹〜黃（木巳）羣叢，及5.茄苳〜榕樹類聯合羣叢。各羣叢之分佈地點及組成的優勢種，與其生育地之方位及風力大小，均有極密切之關係。IV、目前本山區各植物羣落，似均未到達極盛相，正分别循濕生或中生演替序列，向森林羣落推進。演替到最後，勢將因方位及風力大小的不同，而達到兩種氣候極盛相，即迎風坡面變爲以殼斗科爲主之熱帶季風雨林，背風坡面則演替成類似熱帶雨林之中性森林，而以楠木類及榕樹類樹木，爲其共同優勢種。V、經多次調查，以及參閱現存本省各大專學校及研究所標本館之腊葉，已將本山區自生的管束植物，共計186科688屬1,179種，依照Hutchinson J.（1934）氏分類系統，加以排列，舉示各種植物之學名、中名及代表該植物生活型類别之英文縮寫字母，以便於査對與參考。在1,179種中，有約10％之種類，爲恆春半島及其二附屬小島，即蘭嶼與綠島之特産。按照Raunkiaer, C.（1934）氏之生活型分類法計算，本山區有50％之種，屬於挺空植物，又蕨類係數（Pteridophyte coefficient），即蕨類的Ptph-Q.值爲5.26。上述二事實，均顯示南仁山區具有熱帶之濕潤氣候，惟受季風之影響頗大，與實際之氣候條件相吻合。

並列摘要

I. Geographically, the area of Nanjenshan is located nearly in the middle of Hengchun Peninsula, the southernmost part of Taiwan. It faces east on the Pacific Ocean, and borders on Kongkau Chi (brook) in the west. In the area, it is mostly occupied by the complicated low hills which go down eastward to the narrow sandy beach. Though the average altitude of the hills is not too high, being about 300 meters, the climate in this area is very changeable. The annual mean temperature is 25 °C. Nearly 80 % of the rainfall concentrates in the summer, and alternating with a pronounced drought in the winter lasting from four to six months. The annual precipitation increases gradually from 1,900 mm along the coastal region to 3,600mm in the hilly area. The northeast monsoon often prevails during the dry season. In such an area with very changeable climate, it naturally affects greatly the growth of plants. The soils are chiefly composed of light clay with the effective depth about 60 mm and the pH value measures from 5.2 to 5.9. The weather is generally classified as tropical climate. II. Based on the places where the plants grow, the vegetation of the Nanjenshan Area can be, according to our investigation, divided into five types of communities. They are 1. hydrophytic and hygrophytic communities, 2. herbaceous community, 3. closed scrub, 4. forest, and 5. seashore plantcommunity. The physiognomy, structure and composition of various plant communities are carefully surveyed and studied. In order to find out the courses of plant succession, the relationships between the distribution of plants in relation to the environmental factors of this area, closer investigation has also been made. III. The forest community on the hills is the most important vegetation of this area. Aocording to the topographical and climatic conditions, it belongs partly to the tropical monsoon forest type and partly to the tropical rain forest with some indicative characteristics such as stilted roots, plank buttress roots, cauliflory, and many epiphytes etc. By using quadrat method of 37 plots distributed throughout the investigation area and analysis by tubular comparision, the mountain forest community can be again divided into five major associations as follows: ①Castanopsis indica Cyclobalanopsis pachyloma var. tomento-sicupula ~Castanopsis stellato-spina Association. ②Pasania shinsuiensis Cyclobalanopsis championii Association. ③Cyclobalanopsis championii~Castanopsis carlesii carlesii~Pasania brevicaudata~Cyclobalanopsis glauca Association. ④Machilus kusanoi ~ Machilus zuihoensis~Lindera communis~ Engelhardtia chrysolepsis Assooiation. ⑤Bischoffia javanica~Ficus spp. Association. IV. To our observation, up to now it seems that no one plant community in this area has reached the climax. Through the successive stages of both hydrarch and xerarch successions, the vegetation of Nanjenshan Area will be, at last, changed into forest community and ended in two kinds of climatic climax, that is the slopes with the monsoon blowing hard against side will be developed into the tropical monsoon rain forest dominated by the fagaceous trees, and those on the leeward side and locations in most valleys will be seen the mesophytic forests being much like the tropical rain forests codominated by the Machilus-Ficus association.V. Following the system of Hutchinson (1934), a total number of 1,179 species belonging to 688 genera and 168 families of the indigenous and naturalized vascular plants growing in the Nanjenshan Area have been listed. Of the species, about 10% of them are confined to Hengchun Peninsula and the two adjacent small islets, Green Island and Orohid Island (Botel Tobago). Acoording to the classification of plant life-forms by Raunkiaer, 50% of all the species mentioned above are phnaeophytes, while the value of Pteridophyte Coefficient (Ptph-Q.) is 5.26. These Cleaily indicate that the Nanjenshan Area has a tropical moist climate which is evidently influenced by the violent monsoon.