以黃緣螢調查作為生態草溝補償之研究

Abstract

復育螢火蟲為近年來非常熱門的話題，台北許多地方都紛紛投入復育螢火蟲的行列，包括大安森林公園、榮星公園及木柵公園等，也因此帶來不少的賞螢風潮，但復育螢火蟲並非易事，要在高度開發的台北市裡營造螢火蟲的棲地，要有合適的土壤、良好的水質、穩定的水源及適合黃緣螢的微氣候環境。而要怎樣的環境才能使螢火蟲回來就是本研究主題。 螢火蟲為指標性物種，近年來社會高度關注，因有螢火蟲的地方，水質必然好，而復育螢火蟲又具有教育意義，可提高大眾對於環境的關注。本研究地點為台北市文山區永建生態園區北區，園區內營造一生態草溝，目的是為了使螢火蟲能夠回來，作為補償螢火蟲的生態棲地，研究期間進行水質、微氣候及黃緣螢 (Aquatica ficta, (Olivier, 1999)) 調查，包括溫度、相對濕度、水溫、導電度、溶氧、pH值、氨氮、總凱氏氮、總磷、SS與硝酸氮，使用選擇性比例 (Forage Ratio) 探討螢火蟲在選擇棲地選擇上是否有偏愛，且與水質及微氣候因子之相關性。根據本研究發現水中氨氮濃度為影響黃緣螢數量之關鍵因子，黃緣螢偏愛於氨氮濃度低於0.4mg/L之水域，且在黃緣螢復育初期，黃緣螢偏愛水域面積較大之水域。

Recently, the restoration of firefly has become a popular topic. Lots of parks have been engaged in the ranks of firefly’s restoration in Taipei, including Daan forest park, Rongxing park and Muzha park. However, it’s not easy to restore firefly and create firefly’s habitat in the highly developed Taipei city. Suitable soil, good water quality, stable water source and appropriate microclimate are needed for firefly. What environment can attract firefly to come back is the subject of this study. Firefly is an indicator species which receives great attention from human society, and therefore increased public awareness of environment issues. This study was conducted through field investigation to understand the relationship between fireflies and the environmental factors. An ecological ditch was constructed in order to compensate the lost wetland. Four sampling sites were located at Yong-Jian Ecological Park, Taipei. Following data was collected: number of Aquatica ficta,(Olivier,1999) (Line transect methods) , air temperature, relative humidity, water temperature, electrical conductivity, dissolved oxygen, pH, ammonia nitrogen, total Kjeldahl nitrogen, total phosphorus, suspended solids and nitrate nitrogen. The formula, forage ratio, was used to understand what kind of habitat will the fireflies prefer. The results showed that ammonia nitrogen was the key environmental factor for the fireflies, and they preferred to inhabit at the water below 0.4 mg/L ammonia nitrogen. Besides, they preferred to inhabit at lager water area at early stages of restoration.