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摘要


雪霸國家公園的保育工作需以宏觀的尺度進行生態系管理,其基礎必須建立在驅動力的掌握上,尤其是僅分布於大甲溪上游武陵地區,但數量己瀕臨絕種的臺灣櫻花鈎吻鮭(Oncorhynchus masou formosanus)。然而自然營力與人為活動的干擾,常因生物間錯綜複雜的交互作用而變得無法預測。從2005年開始,雪霸國家公園管理處推動「武陵地區長期生態監測暨生態模式(WLTERM)」整合計畫,目前已收集鳥類、魚類、兩棲類、昆蟲及植物調查資料共55608筆(涵蓋15綱99目359科666種生物物種),水質環境資料共2466筆,藻類與有機碎屑調查記錄共401筆,環境溫度監測資料9136筆及河川流量模擬資料1369筆。本研究目的在整合分析從2005~2008年所累積超過4年的資料,找出影響臺灣櫻花鈎吻鮭族群的主要驅動力。藉由複迴歸分析發現成鮭數量時間變化的解釋因子為前一年春季日流量、前一年洪峰次數與前三個月之日流量;亞成鮭數量的解釋因子則為前一季幼鮭數量影響較大;主要解釋幼鮭數量的因子則為前一個月及前三個月之最低日流量。解釋成鮭與亞成鮭數量空間變化的因子為前一季之亞成鮭與幼鮭數量、大小漂石比例、矽酸鹽濃度、氯離子濃度及深瀨比例。藉由重疊分析發現,以附生藻生物量、硫酸鹽濃度、碎石比例及水溫四項因子之解釋度最佳,其中台灣櫻花鈎吻鮭數量與水棲昆蟲數量、硫酸鹽濃度與導電度呈現負相關,但是與鳥類數量、深瀨比例以及大小礫石比例呈現正相關。總而言之,影響台灣櫻花鈎吻鮭族群數量的主要因子為水溫、流量、底質粒徑、棲地型態與水質,因此需設立全流域監測系統進行長期生態監測。同時應積極復育濱岸植被,可協助有效降低升溫效應,減緩暴雨逕流與過濾濱岸營養鹽與有機碳的輸入。底質大小漂石比例亦為鮭魚數量重要影響因子,可能提供鮭魚庇護場所,抵抗颱風洪水的衝擊。

並列摘要


The Formosan landlocked salmon (Oncorhynchus masou formosanus) is an endangered endemic species, which is distributed only in the basin of Cijiawan Stream of Central Taiwan. A collaborative project known as Wulin Long-Term Ecological Research and Modeling (WLTERM) was conducted to continually monitor the changes in the Formosan landlocked salmon, environmental factors and associated biota. For the need and the convenience to exchange data internationally, the data in the project were recorded in XML format. To compensate the need for information searching and presentation, the data has been preseved digitized in a database and is availabe online (http://wlterm.biodiv.sinica.edu.tw). The purpose of this study is to determine the driving forces of the Formosan landlocked salmon by analyzing the over four-year data from 2005-2008. Multiple regression analyses showed that temporal changes in the individual number can be largely explained by stream discharge. However, the spatial changes can be explained by the individual number in the previous season, boulder proportions, concentrations of Si0_2 and Cl^-, and rapid ratio. Redundancy analysis (RDA) showed that periphyton biomass, S0_4 concentration, substrate grain size, and water temperature explained the spatiotemporal changes most. In summary, water temperature, discharge, substrate grain size, habitat type, and water quality were the main factors influencing the abundance of the Formosan landlocked salmon in the streams. Therefore, it is imperative to develop a long-term ecological monitoring system at watershed scale. Riparian plants along the streams should be restored immediately to reduce the rapid increase of water temperature due to global warming and runoff of rainstorm, and to filter the inflow of nutrients and organic carbon from the riparian zone. Boulder might play an important role in resist flooding caused by typhoons should be considered in improving thy habitat of the Formosan landlocked salmon in J the streams.

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