台灣東北部山區湖沼水質與底棲無脊椎動物群聚之關係

Relationships between Water Quality Variables and Benthic Invertebrate Assemblages in Mountain Ponds of Northeastern Taiwan

本研究於2002-2003年每季在加羅湖群之撤退池、豪邁池、偉蛋池、加羅湖等4個池沼進行水質與底棲大型無脊椎動物調查，共記錄底棲大型無脊椎動物2綱7目13科22種（taxa）14,719隻，包括蜻蛉目7種、雙翅目6種、毛翅目3種、半翅目及鞘翅目各2種、貧毛綱及蜉蝣目各1種。其中，台灣大仰泳（Notonecta saramao）與黃基蜻蜓（Sympetrum speciosum taiwanum）爲台灣特有種。另外，以共構分析法（co- inertia analysis, CIA）探討水質因子與物種分布關係中，與腐水性質相關之濁度、氨氮，以及與水體酸化相關之pH值、總硬度等水質因子，最能解釋底棲動物分布形式。其中，貧毛綱（Oligochaeta）建議作爲低腐水池塘之生物指標，叉搖蚊（Dicrotendipes sp.）與四節蜉蝣（Cloeon sp.）作爲水體酸性程度較低之生物指標。

A seasonal survey of water quality and benthic macroinvertebrates was conducted for a mountain lake Chia-Lo and three mountain ponds, Che-Tui, Hao-Mai, and Wei-Tan, in the northeastern Taiwan, 2002 to 2003. A total of 14,719 specimens of benthic macroinvertebrates were collected. They were consisted of 22 taxa, of that seven taxa belonged to Odonata, six taxa to Diptera, three taxa to Tricoptera, two taxa to each of Hemiptera and Coleoptera, and a taxon to each of Oligochaeta and Ephemeroptera. Notonecta saramao and Sympetrum speciosum taiwanum were found to be the endemic species. Relationships between the water quality and the benthic macroinvertebrate assemblages were assessed with the coinertia analysis. The results showed that turbidity and ammonia were related to water saprobity, and pH and total hardness to water acidification. They were the most important water quality variables that explained the formation and distributional pattern of macroinvertebrate assemblages in the mountain ponds. Oligochaeta was recommended as a bio-indicator for the water saprobity, and Dicrotendipes sp. and Cloeon sp. for water acidification.