碩士 / 國立臺灣大學 / 海洋研究所 / 105 / In Taiwan, the reef fish richness is inversely correlated to latitude. So far, no studies have investigated the variation in the functional diversity (FD) around the island. FD in fish assemblages is usually considered as more sensitive than species richness to disturbances and could therefore be used as a better indicator of their ecological resilience to environmental changes. In this study, we aim to assess the roles of the Taiwan reef fish fauna and to characterize regional patterns in FD. In addition, field surveys were targeted to provide preliminary biomass data for a future integration of this information in the evaluation of FD among regions and depths. Total 1,501 species were categorized based on combinations of six functional traits previously identified as critical in the definition of fish function. The number of functional entities (unique combination of trait values) and their characteristics (richness FRic, redundancy FR, over-redundancy FOR and vulnerability FV) were defined and compared among four regions: South, East, West, and North. Fish diversity, density and size were estimated from high-definition videos taken along five 20m-long belt transects set up at two depths (-10 and -40 m) in the South, East, and North regions and converted to biomass. Overall, 419 functional entities (FEs) were identified in the reef fish fauna of Taiwan. Whereas FEs decreased from the south to the north following regional species richness, FRic remained relatively similar among regions. FR and FOR were higher in the South, and FV appeared maximum at intermediate latitudes. Fish biomass showed differences among depths and regions, but additional data are needed in the North to reveal the preliminary pattern observed. At local scale, variations in FEs and FRic are in concordance with worldwide pattern of FD. High-latitudes impoverished fish assemblages offered similar range of functions than diversified tropical assemblages. Increasing diversity in the latter one contributes raising FR, and supports already over-redundant entities. High vulnerability make assemblages potentially highly sensitive to species loss. Higher FV at intermediate latitudes suggested that the loss of a function in fish assemblages may first be characterized by a significant increase of their vulnerability, a pattern that could have been overlooked by global scale analysis. Therefore, FV could act as a potential indicator of more severe changes affecting fish assemblages. Overall, this study provide a new prospect upon which future changes in the reef fish fauna of Taiwan could be assessed.
| Identifer | oai:union.ndltd.org:TW/105NTU05279022 |
| Date | January 2017 |
| Creators | Jian-Wen Chen, 陳建彣 |
| Contributors | 單偉彌 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 50 |
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