台北郊區農水路復育螢火蟲之可行性與其生態工法研究

Abstract

近年在台北近郊野溪中發現本土性螢火蟲黃胸黑翅螢，其除了具有觀賞價值外，亦可作為環境汙染指標。本研究探討利用台北都會區周邊農水路，復育此標的生物之生態工法研究。在待復育區之登峰圳選一觀測站作為實驗區，同時選定已人工復育黃緣螢之虎山溪、自然野溪之聖人瀑布及坪頂古圳共三處觀測站作為對照區，於黃胸黑翅螢幼蟲生長於水中的夏、冬兩季分別觀測各區之氣象、水質、底質及水力環境等相關資料，依據文獻、物理棲地模式(PHABSIM)模擬及現場計測資料進行比較與分析。結果顯示，待復育區的環境因子中，主要為流速超過標的生物之生存基準值，其餘環境狀況均大致適合標的生物生存條件。 為減緩流速，本研究以植栽護岸工及跌水工兩種生態工法進行減緩流速之實驗。結果以每隔8公尺植栽40株/0.25㎡、短草8~10cm高度之渠底短草植栽工法效果最佳，在觀測距離內之75%以上流速可降至適合黃胸黑翅螢生存的流速基準。因此，在台北郊區欲利用分布廣泛之農水路復育黃胸黑翅螢，提高其生態附加價值時，以生態工法對現有流速過快的農水路進行棲地流速改善具有正面效益。

Due to watching glowworms has become a very popular leasure activity and enjoyed by many people in Taiwan. Besides, the number of glowworms could be an indication of the amount of environment pollution in suburban areas. The glowworm is worth to rebreed . The Luciola SP appearing in Taipei suburban areas is the target species in this study.We selected the Deng-feng Jiun,an irrigation ditch preparing to rebreed glowworms in the future, as an experiment station . Three of the comparative stations were selected to compare with the experiment station. One of them was a rebreeded canal located on the Huu-shan Chi, and the others were small creeks located on the Shen-jen Waterfall and the Pin-ding-guu Jiun respectively. The meteorological phenomena, water quality, bed quality and hydraulic condition of all stations were observed in summer and winter respectively, and were analyzed by the physical habitat simulation system model as well as compared with the data obtained from scientific literature. We found that all the measurements observed from the experiment station was suitable for the target species to exist in water habitat except flow velocity exceeded its limit. In order to reduce flow velocity we chose two kinds of ecological workingmethod ,drop and side slope protected by planting herbage, to make an experiment . It was known that the suitable velocity for the Luciola SP to exist in water habitat was from 10 to 30 cm/sec. All methods in this experiment could reduce flow velocity ,however, the method of bed protected by planting herbage which got the above suitable velocity data more than 75 %, obtained the best results of flow reducing. Thus, it is necessary to use ecological working methods to improve the habitat and flow velocity of current agricultural waterways, if we hope to rebreed the Luciola SP in Taipei suburban areas.