| Summary: | 碩士 === 國立臺南大學 === 環境生態研究所在職專班 === 98 === Abstract
A study on the fauna, community composition, and ambient environments of the benthic polychaetes in the intertidal zone of Cigu Lagoon, Tainan, was carried out. Four times of samplings were done in 25 locations among five different intertidal zones from January to October in 2009. A total of 748 individuals in 25 genera belonging to 19 families were sampled in this study. Among these, four families, named Nereidae Neanthes glandicincta ( 37.8% ) , Orbiniidae Scoloplos marupialis ( 13.2% )、 Spionidae Malacoceros indic ( 11.1% ) , and Capitellidae Capitella capitata ( 10.1% ) were the dominant and occupier about 72.2% of the amount of the total benthic polychaetes.
The seawater and terrestrial materials produced impacts on the substrata of intertidal zones. Sediments differed among the five intertidal zones and the tidal current apparently influenced the size of particles. The sediment in the convergent center was the finest and the particle sizes increased with the distance to the central zone. Total organic carbon, Total organic nitrogen and water content negatively related with the sizes of sediments and significantly differed among the five zones ( P < 0.01 ). The two sampling zones located on the banks of Daliao Creek and Cigu River exhibited the highest values in diversity ( 1.84 ) and density ( 1,524 ind/m2 ) respectively. The density of the polychaetes changed seasonally. It reached the peak in January and decreased with time. However, the Capitellidae, especially in the zone of Cigu River, appeared a contrary trend.
The NMDS and CCA technique detected four groups ( cluster ) of sites according to dissimilarity of species and environmental variables. Our results indicate that intertidal zone in Daliao Creek is affected by salinity and organic content of the sediment. The intertidal zone in Cigu River is affected by organic content of sediment. The five sediment grain the lower abundance, the lower number of species and the lower of diversity in Longshan intertidal zone.
Species composition of benthic polychaetes may be used as environmental index , which possess stability and predictability in spatial and temporal patterns. Furthermore, it provides the necessary science references when drawing up coast protection. environmental management and sustainability strategies. Cigu Lagoon is facing erosion and the risk of evanishment . In order to establish the foundation for ecology preservation and to achieve preservation of the Cigu Lagoon ecological systems, more studies are necessary on the benthic polychaetes and terrestrial materials correlation.
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