大礁溪實驗林場蘭花溪之水生甲殼類及脊椎動物相初探

The Preliminary Study on Aquatic Crustacea and Vertebrate Fauna of Orchid Creek in Da-Jiou-Shi Experminetal Forest

陳暐玄(Wei-Xuan Chen) ； 李哲瑋(Jhe-Wei Li) ； 毛俊傑(Jean-Jay Mao)

《宜蘭大學生物資源學刊》 8卷2期 (2012/12) Pp. 73-81

https://doi.org/10.6175/job.2012.82.16

摘要

本研究自2009年6月至9月止，以每週一次的頻度調查，於宜蘭大學大礁溪實驗林場中之蘭花溪行水區，以攔砂壩為界，每10公尺的間距，上下游分別設置10與20個水生甲殼類及脊椎動物相調查的樣點，並比較動物種類組成、形質結構及相對豐富度的差異，同時並記錄水域相關的環境因子，包括：棲地型態、底質石、水深、水溫、雨量。調查期間中，蘭花溪內共記錄到11科14種大型水生甲殼類及脊椎動物；兩科兩種蝦類、兩科兩種蟹類、四科五種魚類、兩科四種蛙類蚓蚓、一科一種蛇類，其中以台灣鏟頷魚（Varicorhinus barbatulus）的數量最為豐富。研究結果顯示因攔砂壩上游有細沙、礫石堆積之現象，使食物源及生殖場減少，可能造成上游的台灣鏟頷魚的族群降低以及生活棲地逐漸減少。以Schnabel法估計台灣鏟頷魚及明潭吻蝦虎（Rhinogobius candidianus）的族群於攔砂壩下游均比上游大，但發現上游台灣鏟頷魚族性成熟比例較下游高，顯示上游的台灣鏟頷魚族群更新狀況不佳。降河洄游性魚類的鱸鰻（Anguilla marmorata）、日本絨螯蟹（Eriocheir japonicus），只在攔砂壩下游調查到。針對優勢魚種進行標記，來了解攔砂壩上下游間之魚類個體交流狀況，發現調查期間上游標記的台灣鏟頷魚，僅有一隻個體在颱風過後，於攔砂壩下游發現，上游則未曾發現來自下游的標記魚隻。顯示了攔砂壩對於魚類族群在洄游與分佈上都造成影響。建議針對蘭花溪水文與地質特性以及水生甲殼類與脊椎動物特性，設計出適合於蘭花溪之魚道或者連續性矮壩，降低攔砂壩對蘭花溪的生物多樣性可能的阻斷效應。

關鍵字

溪流生態 ； 攔砂壩 ； 分布 ； 台灣鏟頷魚 ； 明潭吻蝦虎

並列摘要

From June to September 2009, an investigation of the aquatic Crustacea and vertebrate fauna of Orchid Creek was conducted once a week in Da-Jiou-Shi Experimental Forest, National Han University. The middle stream sediment storage dam was the demarcation point of the different sampling plots and from the headwater (sampling plot A) to downstream (sampling plots B and C) environments. Each linear sampling plot consisted of 10 trapping units, and the distance between two trapping units was 10m. We compared the fauna composition, body condition, population structure, and relative abundance of certain species, and recorded the following environmental characteristic: microhabitat type, substrate, water-depth, water-temperature, and rainfall, within the different sampling plots. Aquatic Crustacea and vertebrate fauna from 11 families, comprising 14 species, were recorded in Orchid Creek. These included 2 shrimp species (from 2 families), 2 crabs species (from 2 families), 4 tadpole species (from 2 families), and 5 fish species (from 4 families), of which Varicorhinus barbatulus appeared to be the predominant fish species. In additions to the above, an ophidian species of the family Colubridae was also recorded. The study results indicated that the sand and pebbles (round stones) accumulated at the upper-dam, probably causing food sources and reproductive space shortages, possibly resulting in a reduction of the population number or available microhabitat for V. barbatulus. The Schnabel population estimated method showed that both V. barbatulus and Rhinogobius candidianus had larger populations in the downstream section of the dam compared to headwater, but V. barbatulus from the upper dam section had higher maturity proportion in population structure than conspecifics from the lower-section, which may be due to improper isolation and pool population regeneration as a result of the dam. In addition, migrating Anguilla marmorata and Eriocheir japonicas were restricted to the downstream region below the dam. A mark and recapture method was utilized on the dominant fish species to determine the population interchange between the upper- and lower-dam, but only upstream-marked V. barbatulus were collected downstream after the typhoon, Morakot. No downstream-marked fish were recorded in the upper-dam region. Our result proved that the sediment storage dam will affect the population structure, distribution, and migration of fishes in Orchid Creek. Considering the hydrological, geological, and biological status, there is a requirement for further improvement of the dam structure in this creek.

並列關鍵字

Rhinogobius candidianus ； sediment storage dam ； species distribution ； stream ecology ； Varicorhinus barbatulus