河川棲地分類方法之研究──以烏溪大旗橋河段為例

The Study of River Habitat Classification--A Case Study of Wu River

河川生物與棲地環境有不可分離的關係，河川棲地面積的減少會直接影響生物的生存空間。河川棲地多樣性是檢視河川棲地品質之重要指標，因此合宜的棲地分類方法顯得非常重要。現有之河川棲地分類方法大致可分為以河川棲地特性及以河川水理特性兩種分類基礎。本研究為探討棲地分類法與水理分類法於棲地分類結果之差異，分別以分類方法之定義類型分布及案例河段模擬結果進行比較。根據研究結果發現：棲地特性分類法與水理特性分類法於定義類型棲地分布比例並無法完全對應。例如在水深≦1 m 及流速≦1 m/s 之流況下，棲地特性分類法之理論棲地類型以深流、深潭及淺瀨為主，水理特性分類法之理論棲地類型則以深潭、淺瀨及淺流為主。案例河段模擬不同流量下之棲地類型分布結果顯示：於高流量時以水理特性法（如福祿數）進行棲地分類可能高估河川棲地之歧異度，建議應輔以其它水理參數（如寬深比等）進行綜合判定。 River habitat classification can be conducted by either the habitat method or the hydraulic method. In this study the difference between two methods of habitat classification is investigated, and the theory and case simulation analysis of habitat classification are compared. According to the study results, two methods of river habitat classification did not exactly correspond. For example, under the condition of water depth≦ 1 m and velocity ≦ 1 m/s, the dominant habitat types were run, pool, and riffle when determined by the habitat method. The dominant habitat types were riffle, run and pool when determined by the hydraulic method. The case study shows that the hydraulic method of habitat classification may overestimate habitat diversity at high flows, thus it should be supplemented by other hydraulic parameters for a comprehensive judgment.

River habitat classification can be conducted by either the habitat method or the hydraulic method. In this study the difference between two methods of habitat classification is investigated, and the theory and case simulation analysis of habitat classification are compared. According to the study results, two methods of river habitat classification did not exactly correspond. For example, under the condition of water depth≦ 1 m and velocity ≦ 1 m/s, the dominant habitat types were run, pool, and riffle when determined by the habitat method. The dominant habitat types were riffle, run and pool when determined by the hydraulic method. The case study shows that the hydraulic method of habitat classification may overestimate habitat diversity at high flows, thus it should be supplemented by other hydraulic parameters for a comprehensive judgment.