水生昆蟲在不同流速與底床之分佈與行為作為生態工程設計之依據

Distribution and Behavior of Aquatic Insects in Different Velocity and Bed Materials as A Basis for Ecological Engineering Design

周心儀(Hsin-Yi Chou)

指導教授 ： 張文亮

國立臺灣大學/生物資源暨農學院/生物環境系統工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.00025

摘要

為改善傳統河川整治工程對生態環境之衝擊，因此發展了生態工法的概念。本研究調查台灣東北部四條圳路，分別為台北縣金山鄉員潭子圳、三芝鄉八連溪埔頭圳及宜蘭縣枕山鄉枕山圳和內城鄉內城圳，於2003年3月、6月、8月及11月之水生昆蟲分佈及物理性環境因子的變化。利用調查資料進行相關性分析、建立迴歸模式並計算各物種在不同流速下之出現機率，以提供溪流生態工法量化之參考。
研究多樣性指標和環境物理因子之關係，顯示d90愈大，生物多樣性愈高；而和流速平方為負相關。石礫愈大可在愈低之流速達到高生物多樣性之結果。流速在0.62∼0.73m/s時d90為5∼20cm可達到高生物多樣性。
研究發現，若僅考慮適應流速之情況水生昆蟲可概分成三類，一為嗜流種，如石蠶、扁泥蟲等，在流速大於0.82m/s時具有優勢性。另一為靜流種，如水蠆等，在流速0.2-0.3m/s具有優勢性。最後為介於靜流種與嗜流種之間的族群，如石蠅、水甲蟲等，主要棲息於流速0.55∼0.62m/s之環境。
溪流生態工法之設計，應避免棲地之單一化，以達生物多樣化之目標。流速的變化至少需達上述三種，並且盡量增加底床粒徑歧異度。
水生昆蟲為溪流生態系食物鏈底層物種，其生理特性對環境變化具有高敏感性。流速為決定優勢物種消長之關鍵性物理因子，本研究以水蠆為實驗對象，利用圓統計之概念，探討其攀附在圓柱體及長方體石塊時，面對不同流速之反應，以作為溪流生態工程設計之參考。
水蠆攀附於圓柱體石塊上時，於0.23∼0.51m/s之流速下，平均角之群聚度不顯著，表示具有較高之行動力。攀附於長方體石塊時，於0.23∼0.67m/s之流速下，平均角之群聚度顯著，表示其行動能力不高。於較小圓柱體或長方體石塊上，平均角之偏差值較小，愈大的石塊提供愈多的微環境選擇性，使水蠆移動範圍愈廣。

關鍵字

粒徑 ； 圓統計 ； 溪流生態工法 ； 水生昆蟲 ； 水蠆 ； 流速 ； 溪流生態工程

並列摘要

In order to improve the impact of the traditional river stream remediation on ecosystem, the concept of ecological engineering has been developed. This investigation concerns aquatic insect fauna distribution and physical habitat factors in Yuan-Tan-Zi canal, Pu-Tou canal, Zhen-Shan canal and Nei-Cheng canal in northeastern Taiwan. The sampling was conducted in March, June, August and November, 2003. Various statistical analysis were used, including Pearson correlation, multiple regression model and interspecific normal distribution curve interaction analysis. It is hoped that the analysis in this study can be served as a reference for stream ecological engineering in Taiwan.
By analyzing the relationship between the Shannon index and the physical habitat factors, it showed that the biodiversity increased with d90 and decreased with the square of water velocity. With the water velocity between 0.62-0.73 m/s and d90 between 5-20 cm, there was high biodiversity. Thus the Shannon index can be an important index of stream ecosystem.
As a result of the field experiments, we can classify the condition of aquatic insects adapting to water velocity into three types: (1) swiftwater species, such us caddis-fly, water-penny and so on, are the dominant insects in flow of water velocity up to 0.82 m/s, (2) Stillwater species, such us damselfly and so on, prefer the water velocity between 0.2-0.3 m/s, (3) the species between swiftwater and stillwater, like stone-fly, water-beetle and so on, live in water velocity between 0.55-0.62 m/s.
We suggest to implement ecological engineering methods, which aim to form various flows and stream bottom sediment diversity, to enhance the biodiversity and to enrich the habitat environment.
Aquatic insects are the species of the bottom-end of food chain in stream ecosystem. Their physiological characteristics are sensitive to the changes of the physical environment. The water velocity is the key physical factor of their thrive or decline. In this study, circular statistics were used to analyze the behavior of damselflies climbing over to the rectangular and cylindrical stones under different water velocities as a reference for ecological engineering design.
When damselflies climb over to the cylindrical stones, the insignificant cluster of mean angle under the water velocity of 0.23~0.51m/s indicates that they have better mobility. When the damselflies climb over to the rectangular stones, the significant cluster of mean angle under the water velocity of 0.23~0.67m/s indicates that they have better mobility. The ones on the smaller rectangular or cylindrical stones, mean angle deviations are less. Larger stones provide more diversity of the micro-environment, and enlarge the habitats of the damselflies.

並列關鍵字

water velocity ； sediment ； damselfly ； circular statistics ； stream ecological engineering ； stream ecological engineering ； aquatic insects

參考文獻

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