Community Dynamics of Neritidae along the Coast of Hengchun Peninsula, Southern Taiwan

• Main Authors: Jia-Yi Shih, 施佳宜
• Other Authors: Koa-Jen Jong Ph. D.
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/vksz4x

碩士 === 國立嘉義大學 === 生物資源學系研究所 === 96 === The aim of the thesis is to study the dynamics of community of nerites around the Hengchun Peninsula, because there were few studies concerning geographical distribution of nerites in Taiwan; and the results of the study might be good references for environmental surveys. Hengchun Peninsula locates at the southernmost of the island, belongs to the tropic. Neritidae (Prosobranchia) animals inhabit in intertidal zones of rocky coasts in the tropical and subtropical areas. The bimonthly samplings have been made from May 2006 to September 2007. Ten sites were spotted for the workouts. The types of studying sites were coral reef, sandstone, gravel, and artificial structure. Transect sampling method was followed to collect the animals at high, middle, and low tidal zones. Each survey was made in an area of 16 m2. There were 18 species of nerites collected. Three species belong to genus Clithon, and the other 15 species are genus Nerita. On the coral reefs, 17 species of both genus were collected, 16 species of Nerita on the sandstones, 3 species of Nerita and1 species of Clithon on the gravels near outlet of the river, and 9 species of Nerita on the artificial structures. The new generations of Nerita might take part in the populations at the cool season (November~ January), and those of Clithon might do at the hotter season (July~ September). The nerites on the coral reefs had the highest Shannon-Weaver index and Pielou’s evenness index, and both the lowests occurred on the gravels. The result of Cluster analysis showed that there was very low similarity between the composition of the nerites on both the coral reefs and the artificial structures constructed on the coral reefs. At natural coast, the nerites prefer to inhabit in high tidal zones and on the artificial structures; few individuals were found at high zone, maybe because of smooth surface; and the most gathered at shady middle zone. The November has the highest Shannon-Weaver index of species composition of nerites, and the lowest in May. Both May 2006 and January 2007 has the highest Pielou’s evenness index, and July 2007 the lowest. Most of habitats of the west coast of the Peninsula are coral reefs, some of which supply with groundwater; the east coast has more versatile habitat of coral reefs, sandstones, and gravels of river mouth, and coral reefs occupy most of the southern coast. Being highly porous, the habitats of the west coast contain higher biodiversity, but large number of tourists might make southern coast more biologically monotonous. Most of the habitats of the east coast are less porous than those of the other two coasts, but this area is lowly populated, far from interesting areas, and has higher diversity than the southern coast, but lowers than the west coast.