南麂列岛海洋自然保护区岩相潮间带软体动物种类组成与数量分布

Mollusk species composition and quantity distribution of intertidal zone in Nanji Islands Marine Nature Reserve

根据2013年11月、2014年2月、5月、8月对南麂列岛岩相潮间带7个断面进行的生物资源定量和定性调查所获得的软体动物资料,研究了该区域软体动物的种类组成和数量分布特征。结果显示：（1）共鉴定出软体动物种类63种,隶属于3纲13目34科52属。春、夏、秋、冬季出现的种类数分别是48种、48种、45种、41种。（2）不同季节软体动物资源数量不同,在个体数上是春季〉秋季〉冬季〉夏季;在重量上则是春季〉秋季〉夏季〉冬季;软体动物平均个体数和生物量分别为506.5个/m^2和801.54 g/m^2,且以春季为最大,冬季为最小。（3）不同潮区的软体动物平均个体数不同,具体是中潮区〉低潮区〉高潮区;生物量差异也很明显,具体是低潮区〉中潮区〉高潮区。（4）不同季节的优势种差异较大,但条纹隔贻贝是一年四季共有的第一大优势种。研究表明,由于受海流、地形、风浪等环境因素的影响,南麂列岛潮间带软体动物在不同季节、不同断面的分布差异较大。同时,通过与历史资料的对比发现,近二十年来,南麂列岛软体动物的物种数及数量有一定程度的减少。

Based on the mollusks＇ data which were obtained by biological resources quantitative and qualitative investigation in seven sections of the intertidal zone of Nanji Islands in November 2013, February, May and August2014, this paper studied the species composition and quantitative distribution of mollusks in this area. The results are as follows：（1） A total of 63 species of mollusks were identified, which belong to 3 classes, 13 orders, 34 families and 52 genera. The numbers of species that appeared in spring, summer, autumn and winter were 48, 48, 45 and41, respectively.（2） The numbers of mollusks resources was different in different seasons. As for the number of individuals： spring autumn winter summer; As for the weight： spring autumn summer winter; the average individual number and biomass of mollusks are 506.5/m^2 and 801.54 g/m^2, and the maximum was in spring and the minimum was in winter, respectively.（3） The average numbers of mollusks varied in different tidal areas： middle tidal zone low tidal zone high tidal zone. The differences in biomass were also apparent： low tidal zone middle tidal zone high tidal zone.（4） The dominant species varied greatly in different seasons, but Septifer virgatus was the first dominant species throughout the year. Because of the influence of environmental factors, such as currents,topography and wind waves, the distribution of mollusks in Nanji Islands varied greatly in different seasons and sections. At the same time, compared with the past data, the kinds of and the number of mollusks in Nanji Islands have decreased to some extent in recent 20 years.