颱風後水棲昆蟲之拓殖模式

Colonization Patterns of Aquatic Insects after Typhoons

本研究藉由颱風侵襲後進行較密集之調查，以了解颱風影響後水棲昆蟲之拓殖情形。調查結果顯示水棲昆蟲群聚於颱風影響後有趨向於颱風前之結構型式發展；優勢分類群於颱風引起之環境衝擊後，由Baetis spp.及Ecdyonurus spp.轉變為Pseudocloeon spp.及Rhithrogena spp.。岸邊之調查顯示Baetis spp.及搖蚊科（Chironomidae）偏好分布於流速較緩之河岸，Hydroptila sp.於河岸隨絲狀藻呈零散分布。依功能性攝食群探討，颱風影響後，水棲昆蟲拓殖初期捕食者比例較高，之後捕食者比例逐漸下降，刮食者比例上升；而刮食者相對密度升高後，集食性採食者相對密度也逐漸升高，故之後刮食者相對密度呈下降趨勢；濾食性採食者族群密度顯示較以往低；刺吸者比例較以往高。

To understand the colonization patterns of aquatic insects by the impacts of typhoon, an intensive investigation was carried out after typhoon hits from April 2007 to March 2008. The study found that the structure pattern of the aquatic insects community shifted back toward that of pre-typhoon period. The pre-typhoon dominant taxa Baetis spp. and Ecdyonurus spp. were replaced by Pseudocloeon spp. and Rhithrogena spp. after environmental impacts by a typhoon. Baetis spp. and chironomids distributed in slow running water, while Hydroptila sp. scattered amongst filamentous algae at the bank. Among the functional feeding groups, a higher ratio of predators was found in the early stage of colonization after typhoon disturbance. The proportion of predators decreased gradually with an increased abundance of scrapers, followed by an increase in relative abundance of collector-gatherers, which subsequently caused a decrease in scraper ratio. Population density of collector-filterers was also found to be lower than that in the pre-flood period while the ratio of piercers increased.