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標題: 大甲溪中下游植物分佈之研究
Studies on the distribution og stream-edge plants in the middle amd downstream area of Tachiashi
作者: 廖培智
Liao, Pei-Chih
關鍵字: Tachiashi
riparian vegetation
出版社: 植物學系
摘要: 大甲溪是臺灣中部的主要河川,主流全長124公里,發源於中 央山 脈之雪山及南湖大山,於臺中縣高美附近入海。濱溪植群是指生長在河川 兩岸石礫區及沙洲上的植群,有週期性的洪水干擾。雨季時受河水的沖刷 與淹沒,旱季時乾燥缺水,因此植物相變化劇烈。耐水淹及耐旱便是河濱 植物的特性。 本研究以線截法調查15 個樣區的植群組成,可將大甲溪中、下游植物的植群以河床寬度60公尺為 界區分為兩種類型:下游植群型與中游植群型。前者的特色是植物種數多 、且主要優勢種均為甜根子草、象草、紅毛草、咸豐草及巴拉草;後者的 特色則是植物種數少,不同河段植物組成的差異性也較大。 河濱優勢植物依生長位置的分佈式樣可分3種類型:(1)以甜根子草為代表 的耐水型植物;(2)以咸豐草為代表的泛佈型植物及(3)以五節芒、毛鞘蘆 竹為代表的專佈型植物。耐水型植物主要以地下莖萌灞新植株的方式來繁 殖,且大多長在河岸近水區,能在洪水後以殘存的地下莖繼續生長。泛佈 型植物主要以種子繁殖的方式散佈,種子藉動物或風力傳播,再加上種子 優異的發芽率,廣泛的分佈於河床上。專佈型植物的出現則侷限在特定地 區,可能是因為需要特定種源散佈路徑的生長環境。
Tachiashi is one of the principal rivers in center Taiwan. It originates in Hsueshan and Nanhutashan of Central Mountains of Taiwan, and it flows into Taiwan Strait passing over 124 km. The plants of riparian vegetation are growing on the sides of both riversides and riverbed. Their growth are influenced by the periodic flood. Those sites are eroded by river water in the rainy season and are arid in the droughty season.Therefore, the diversity of those plants are dependent upon their environmental conditions. The riparian plants are tolerant toward wateriness and drought. The composition of riparian vegetation and the distribution of riversideplants in the middle and downstream areas of Tachiashi were investigated by employing the line- transect sampling method at the fifteen plotted sites. The vegetation distribution may be divided into two types : (1) downstream- area vegetation and (2) middle-area vegetation. The former is characterized by its higher richness in plant diversity and having some dominant species : Saccharum spontaneum , Pennisetum purpureum , Rhynchelytrum repens , Bidens pliosa and Brachiaria mutica ; the latter lower richness and having various vegetation composition in the different plots. According to the growing locations , riparian vegetation can be categorized into three types of distribution patterns. (1) Watercourse-tolerant distribution pattern , e.g. Saccharum spontaneum which is a perennial herbaceous plant growing near the river and propagating by its subterranean stems. (2) Widespread distribution pattern, e.g. Bidens pilosa ,propagating by its seeds and widely distributing in riparian area by means of the highly germinating rate of seeds dispersed by animals or wind . (3) Specialized distribution pattern , e.g. Arundo donax var. coleotricha and Miscanthus floridulus , appearing in the special sites where probably have a proper disseminating environment.
Appears in Collections:生命科學系所



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