本研究係探究北勢溪水棲昆蟲之羣聚結構;由調查結果得知,此羣聚結構是由8目42科83種水棲昆蟲所組成,其中蜉蝣目、襀翅目、雙翅目及毛翅目為優勢族羣。由水棲昆蟲之種類數及個體數可獲知水棲昆蟲在各採樣站之年中變化。各採樣站之水文等環境因子與季節間有顯著性差異;至於水棲昆蟲之種豐度(Richness)、羣聚平均繁異度(Diversity)和平均均勻度(Evenness)在各站及季節間均有顯著性差異。在水棲昆蟲之食性方面,依不同食性功能羣作two-way ANOVA分析,比較其與各採樣站及季節間之關係發現,各種食性之水蟲,除刮食者(Scraper)之外,不同採樣站與季節間有顯著性差異。而不同食性之水蟲在河域中之分佈則頗符合河流連續性觀念(River Continum Concept)。
The extensive series of sampling from Pei-Shih Stream were used to investigate the community structure of aquatic insects from Aug., 1987 to Jul., 1988. The nymphs of Ephemeroptera are the most abundant, occupying 55.5% of the total number of individuals. According to two-way ANOVA, the community indice have significant difference in sites and seasons, except the evenness in seasons; but these have no interaction between in sites and seasons. As comparing the functional feeding groups, there are significant difference in sites and seasons, except the scraper in sites. From the results, it was found that the distribution patterns of the aquatic insects were accordance with the River Continum Concept.