【摘要】 20 0 2年 8月对西沙永兴岛珊瑚礁与礁坪生物进行了生态学调查。珊瑚礁调查采用选取断面布设样框的方式进行覆盖率的定量调查 ,水下照相和录相拍摄的珊瑚种类作为定性调查资料 ,并将调查结果与 1978年结果对比 ,以说明该区域珊瑚礁的变化趋势。礁坪生物的采样采用取样框和走样线相结合的方式 ,获取定性定量资料 ,并采用Shannon Weaver多样性指数 (H′)和Pielou均匀度指数 (J)来说明永兴岛礁坪生物的物种多样性和物种分布的均匀性情况。结果表明 ,永兴岛珊瑚种类丰富 ,共发现 2 9种珊瑚 ,造礁珊瑚覆盖率较高 ,但 2 0多年来珊瑚有较明显的退化趋势。礁坪生物初步鉴定有 5 4种 ;平均生物量为 395 78g/m2 ,平均栖息密度为 6 3ind/m2 ;生物数量和物种多样性的水平分布趋势一致 ,即礁坪北侧最高 ,南侧居中 ,西侧最低 ,这种现象与岛屿西侧受人类活动干扰程度较大有关 ;数量的垂直分布 :生物量为低潮区 >中潮区 >高潮区 ,栖息密度为高潮区 >中潮区 >低潮区 ;物种多样性的垂直分布存在自高潮区向低潮区递增的趋势。更多还原

【Abstract】 The ecology of coral reef and intertidal benthos around Yongxing Island were investigated in August 2002. Quantitative quadrat sampling on selected benthic transects and qualitative video recording were used in our investigation. The results obtained were then compared with those since 1978 in order to find the coral reef changing trend during past 20 years. The intertidal benthos surveyed through sampling and observation were analyzed using Shannon-Weaver index ( H ′) for diversity and Pielou’s index ( J ) for everness. The results indicated that the coral was abundant with 29 identified species. Coral coverage was high (42.1%—93.4%) but there had been serious degeneration during last 20 years. A total of 54 species of intertidal benthos were identified. Mollusk and shellfish were the dominant species accounting for 64.8% of the total number of species. In the west part of the reef platform,biological diversity and abundance were relatively low because of frequent human disturbances. Towards the south and north (near Yongxing Island) parts,both biological diversity and abundance tended to be a natural pattern. Same pattern was also found in the average population density whose average was 6.3ind/m 2. The average biomass of intertidal benthos was 395.78g/m 2,among which the algae were the dominant organisms followed by shellfish. Biomass,density and diversity decreased from low tidal zone to high tidal zone. Vertical everness in low tidal zone was higher than that of high and middle tidal zone. However,no significant variation in horizontal everness was observed except for a minor one in intertidal benthos species.更多还原