苗栗淺山溪流生態系代謝與調控因子之探討

Ecosystem Metabolism and Influencing Factors of Miaoli Lowland Streams

蔡函霓(Han-Ni Tsai) ； 林幸助(Hsing-Juh Lin)

《濕地學刊》 4卷1期 (2015/12) Pp. 91-109

摘要

生態系由生物群集及其所處環境所構成，僅以特定生物爲研究對象並無法將生物與環境因子的交互作用納入考慮，因此生態研究應以「生態系」爲基本單元。本研究透過生態系統代謝研究，以苗栗縣飛鳳與後龍兩溪爲例，來探討臺灣淺山溪流的生態系功能，並探究影響溪流生態系功能的主要因子。生態系統代謝包含總基礎生產量(Gross Primary Production, GPP)及群集呼吸量(Ecosystem Respiration, ER)，可反映生態系統中能量生產及消耗之狀態。本研究結果發現春夏季的代謝作用較爲旺盛，而各季的飛鳳溪與後龍溪多屬於異營生態系，需外源輸入能量來維持生態系統運作。影響兩溪流系統代謝的因子不盡相同，調控飛鳳溪GPP的主要因子爲流速與磷酸鹽；後龍溪GPP的影響因子則爲植被鬱閉度所造成光度變化；流速與磷酸鹽會顯著影響飛鳳溪的ER;後龍溪ER的調控因子較少，僅底層蓄積細顆粒有機碎屑影響較爲顯著。因此，影響苗栗淺山溪流GPP的主要驅動力爲流速、營養鹽與植被鬱閉度；ER的主要驅動力則爲流速、營養鹽與有機碎屑。苗栗兩條淺山溪流的生態系功能雖有所差異，但皆與濱岸生態系有密切連結，故應將溪流與濱岸視爲一個整體生態系統，對溪流進行研究與開發利用時也需將兩 者一併納入考慮。

關鍵字

淺山溪流 ； 系統代謝 ； 基礎生產 ； 群集呼吸

並列摘要

An ecosystem is composed of organisms and surrounding environment. Study on specific organism will exclude the interactions between organisms and abiotic factors. When we perform an ecological study, the basic unit for research should be “ecosystem”. In this study, we determined the system metabolism of Miaoli lowland streams, in order to examine the ecosystem function. We also tried to explore main factors that regulate ecosystem functioning. System metabolism represents the rates of production and respiration of organic matter, which is an integrated measure of a system. During the research period, system metabolism was higher in spring and summer, and all the study sites were heterotrophic. Energy supplied from adjacent riparian zones helped to maintain the system functioning. Factors regulate system metabolism were different in the streams. Velocity, and phosphate concentration were main factors for the production rate of the Fei Fong Stream. Coverage significantly affected the production rate of the Hou Long Stream. The regulators of respiration rate in the Fei Fong Stream were velocity and phosphate concentration. Main factor significantly affected the respiration rate in the Hou Long Stream was organic matter concentration. In short, the driving forces for Miaoli lowland streams’ production rate were velocity, nutrient concentrations, and coverage. The driving forces for Miaoli lowland streams’ respiration rate were organic matter, velocity, and nutrient concentrations. The linkage between stream and riparian ecosystems were strong for the two lowland streams in Miaoli. This suggests that we have to consider them together as a whole ecosystem for research or exploitation.

並列關鍵字

lowland stream ； system metabolism ； production ； respiration