河濱植生與河川基流量寬度關係之研究

Relationship between Riparian Vegetation and Base-Flow Width of Streams in the Southern Taiwan

河濱植生生長之河濱棲地受河川水文特性差異之影響，因此河濱植生之分布特性應與河川水文特性有關。本研究利用實測流量-河寬資料，透過流量延時曲線概念與基流量估算經驗式，推估基流量所對應之基流河寬，藉由基流河寬與河濱植生首現位置進行無因次植物首現寬度W之計算，探討河濱植生與基流量之關係。由研究結果顯示無因次植物首現寬度W與植物生活型之關係為W喬木>W灌木>W多年生草本>W一年生草本，此河濱植生與水文特性結合之定量方法，可作為一考量河川生態系統觀點之河川治理參考。同時透過相似度係數之計算顯示各個樣區間之相似度係數不高，即各樣區之河濱植生各有其區域性之特色。 Distribution and community structure of riparian vegetation vary according to hydrologicalcharacters of streams. We surveyed the riparian vegetation at four sites of three drainages in the southernTaiwan in February to April 1992. We also obtained the data of daily flow rates and flow widths of thestreams near the sites from Water Resources Agency for 1994 to 2001. Using the latter data, daily baseflowwidths of the streams were calculated, using the daily flow duration curve and empirical base-flowequation. The base-flow widths were compared with the riparian vegetation surveyed to estimate thevegetation's first appearing dimensionless widths (W-values). It was found that the W-values variedaccording to vegetation forms in the order of Warborescent plants> Wshrubs> Wperennial plants > Wannual plants. Theriparian vegetation was characterized locally with structures of different plant communities that had lowsimilarity coefficients among the study sites. The quantity analyses of the riparian vegetation in combination with hydrological characters may be useful for stream management.