請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/75367
標題: | 哈盆溪環境因數、幹擾、及魚類刮食對藻類群聚消長的影響 Effects of environmental factors, disturbance, and grazing of fish on the succession of algal communities in Happen Creek |
作者: | Hung-Yu Wang 汪鴻玉 |
關鍵字: | 藻類,生物量,幹擾,台灣鏟頷魚,刮食,關鍵植食生物,選食性, algae,biomass,disturbance,Varicorhinus barbatulus,grazing,keystone herbivore,feeding selectivity, |
出版年 : | 2003 |
學位: | 碩士 |
摘要: | 本研究目的在於探討哈盆溪流域激流與靜水環境,環境因數與臺灣鏟頷魚對於附生藻類群聚消長的影響。於2002年3月到2003年3月期間,在哈盆溪流域選擇六個樣站共鑑定出38種矽藻、11種藍綠藻,與7種綠藻。利用主成分分析,分析各樣站的藻類群聚組成、生物量與14項溪流環境因數,結果發現在激流棲地環境下,影響藻類群聚之重要因數有:流速、深度、溶氧量、導電度與硝酸鹽;靜水棲地則以酸鹼度、濁度與磷酸鹽為主。在沒有幹擾情況下,激流棲地的藻類生物量(chlorophyll a, AFDM)與藻種多樣性(Shannon index)均高於靜水棲地。此外,本研究還進行幹擾對藻類群聚影響之試驗,發現幹擾在兩種不同棲地類型,除了都會明顯降低藻類生物量與藻種多樣性,也改變藻類物種組成,使群聚中矽藻的相對豐富度減少,而激流棲地的綠藻與靜水棲地的藍綠藻之相對豐富度則增加。其中生活週期較長以及抗壓性高的藻種,如Cocconeis placentula與Gongrosira sp.等在幹擾情況下成為優勢物種,取代了早期佔優勢的藻種,如Oedogonium sp.。 台灣鏟頷魚(Varicorkinu, barbatulus)為哈盆溪最優勢魚種,以刮食附生藻類為食,為瞭解台灣鏟頷魚的刮食對藻類群聚之影響,於2002年12月至2003年3月進行野外試驗,將經過台灣鏟頷魚刮食處理的藻類群聚與未幹擾、人為幹擾以及自然情況下收集的藻類群聚分析,作進一步短期生物因數作用之探討。結果發現台灣鏟頷魚刮食除了使藻類生物量降低外,亦造成藻類群聚結構改變,它除減少矽藻的相對豐富度外,並增加了激流樓地的綠藻、與靜水棲地藍綠藻的相對豐富度。另外評估自然情況下,溪流中所有刮食生物刮食對藻類的衝擊程度,與僅受台灣鏟頜魚刮食復之藻類群聚組成結果相似,因此,台灣鏟頷魚係哈盆溪主要影響附生藻類群聚組成與生物量的刮食生物(keystone herbivore),對於藻類的作用機制屬於隨機非選食性地刮食。 The goal of this study was to elucidate the effects of environmental factors and grazing of fish on the succession of algal communities. A study on the interaction between environmental factors and algal communities in Hapen Creek was conducted from March 2002 to March 2003. Six study sites, including lotic and lentic habitats, were chosen. A total of 38 diatom species, 11 of cyanobacteria, and 7 of green algae were identified from these sites. The results of PCA ordination showed that higher correlation coefficients were obtained between the algal communities and those variables such as current velocity, depth, DO, conductivity, and nitrate, suggesting that these variables should have played more important roles than others in determining the structure of the algal communities and the growth of algae in riffles, although pH, turbidity, and orthophosphate were found to have effects on algae in pools. Under undisturbed condition, both of the algal biomass (in terms of chlorophyll a and AFDM) and Shannon species diversity index in lotic habitats were higher than those in lentic habitats. Under disturbed condition, in contrast, there were decreases in the algal biomass and diversity in either habitat, and, as a result, certain changes in community structure. It was found that habit disturbance caused significantly a lowering in the abundance of diatoms, but an enhancement in that of green algae in the riffles as well as cyanobacteria in the pools. This study showed that when algal communities were confronted by frequent disturbance, those of long-lived and more resistant species, such as Cocconeis placentula and Gongrosira sp., would dominate over others and replaced consequently the early invaders such as Oedogonium sp. Taiwan shoveljaw carp (Varicorhinus barbatulus), feeding on attached algae, is the most dominant fish in Hapen Creek. The study of the grazing effects of V.barbatulus on algal communities in both of the lotic and lentic habitats in Hapen Creek was done from December 2002 to March 2003. The collected algal assemblages from grazed treatment (viz., grazed by V. barbatulus) would be analyzed with those from undisturbed, disturbed, and exposed treatments (viz., boulders exposed to grazers in streams) to examine the short-term biotic interactions. The results showed that the grazing of V. barbatulus not only reduced the biomass of the algae, but also altered the structure and composition of algal assemblages. The grazing effect of V. barbatulus has given rise to a decrease in the relative abundance of diatoms and an increase in greens in lotic habitats or blue-greens in lentic habitat as well. The composition of algal assemblages of grazed treatment was similar with that of exposed treatments. Hence, it was found that V. barbatulus exerted a density-dependent consumption effect on the attached algae and might thus be considered a keystone herbivore in the study area. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/75367 |
全文授權: | 未授權 |
顯示於系所單位: | 動物學研究所 |
文件中的檔案:
沒有與此文件相關的檔案。
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。