姊妹泉圳路生態復育對中華花鰍棲地選擇之影響

Abstract

農田水路的發展型態已不再只追求引水灌溉之便利性，近年來，生態工程逐漸受到重視，生存於圳路內之魚蝦蟹貝和周邊植物得以恢復生存空間。苗栗農田水利會砂岡圳姊妹湧泉第一期生態工程(上圳)，拓寬渠道斷面並營造深潭之棲地型態，圳內亦設置固床工減緩流速，此一工程施作營造出適合中華花鰍覓食、繁殖和躲避之棲息環境。經過2009年5月和7月之野外調查，相較於未實施生態工程之姊妹泉下圳，上圳之水流速度較緩、水深較深，且花鰍數明顯較多，結果顯示生態水路之營造成果，使圳路與農田之間發揮生態廊道的效益。 由野外調查、水質和土壤之實驗分析，可發現中華花鰍對深水潭、草溝和砂土有偏愛之選擇性，而對深流、急流和壤土則選擇迴避，水質檢測結果選取12個變項，以多變量統計中的因子分析進行主成分因子之萃取，取得3個因子之特徵分別為：營養因子、鹽分因子和光合作用因子，配合生物指標─中華花鰍數量，結果可得知花鰍出現範圍屬於中營養區、低鹽分區及日照量充足但有適度遮蔭或植物為屏障的水域環境。 室內實驗結果發現，有底質之水域環境，比無任何底質之環境更有利於中華花鰍抵抗增強中的流速，本實驗中以小礫石(4.70-12.70mm)最有助於作為花鰍胸鰭之支撐點，而支持花鰍抵禦之平均流速到達0.43m/s；雄性花鰍胸鰭的力量和外型構造在面對水流衝擊下比雌性花鰍之胸鰭更具有對抗水流的優勢，而花鰍各部位(頭部、胸鰭、背鰭)角度的表現，則隨水流速度增加而減少。

The development of agricultural canals not only pursues the convenience of irrigation but also promotes the importance of ecological engineering. As a result, fishes, shrimps, crabs, shellfishes and vegetation can restore and survive in agricultural canals. Jie-Mei Spring canal, attached to Miaoli irrigation associations, has broadened channel, at the first stage of ecological engineering (left canal). Creating pools and setting stone pitching to retard velocity. The construction is to provide a habitat for Cobitis sinensis to feed, reproduce and avoid predators. Through the field investigation in May and July in 2009, the left canal is compared to the right canal which doesn’t implement ecological engineering. The left canal has lower flow velocity, deeper depth and more Cobitis sinensis. The results show the benefits of ecological corridor among canals and fields. After field investigation, water quality and soil of the experimental analysis, it can be found Cobitis sinensis prefers environment where are abundant of deep pools, grass ditches and sand. On the other hand, Cobitis sinensis avoids in run, riffle and loam. Twelve water quality variables are combined into a data matrix and subjected to the factor analysis. Three principle components are extracted as nutrient factor, salinity factor, and photosynthesis factor. The results demonstrate that Cobitis sinensis distributes in middling nutrition, low salt, abundant sunshine and vegetation-covered area. The experiment results in lab shows that base-substance is useful to resist velocity for Cobitis sinensis. Gravel (4.70-12.70mm) is a best base-substance to support Cobitis sinensis swimming in this experiment. The critical swimming speed arrives 0.43m/s. Male Cobitis sinensis’s strength and shape of pectoral fin has more advantages to resist water velocity than female. Angles of the body (such like head, pectoral fins, dorsal fin) decrease as the flow rate increases.