Community Structure And Succession Rules Of Molluscs In The Intertidal Zone In Nanji Islands Marine Reserve

This paper focuses mollusc species composition,quantitative temporal and spatial distribution,species diversity and community structure characteristics on intertidal zone in Nanji Islands.The data from the Nanji Islands intertidal mollusk resources survey in November 2013(fall),February(winter),May(spring)and August(summer)of 2014.Use abundance and biomass of mollusks as the number of indicators,the region intertidal mollusk species composition,quantitative distribution,dominant species changes,changes in community structure and succession were studied.The results are as follows:(1)According to the survey sample was obtained by the analysis identified a total of77 kinds of molluscs,belonging to 3 classes,13 orders 37 families and 56 genera.Spring,summer,autumn and winter were identified 55 kinds,61 kinds,59 kinds,47 kinds of mollusks.Spring and autumn are 3 kinds of dominant species,summer,winter dominant species are five kinds.Septifer virgatus became the first dominant species in each quarter.In the horizontal distribution of mollusks,the average abundance is arranged autumn> spring>winter> summer,the average biomass is arranged summer> autumn> on spring> winter,vertical distribution,the average abundance and average biomass are middle tidal zone> low tide zone> high tide zone.(2)Molluscs average Pielou evenness index(D)was 2.19,the average Margalef species richness index(J ’)was 0.58,the average Shannon-Wiener diversity index(H’)was 1.51,but each quarter have a big gap,Shannon-Wiener diversity index(H ’)is winter(1.61)> spring(1.57)> summer(1.54)> autumn(1.32).Similarity between different season is spring(38.68%)> summer(37.26%)> autumn(36.21%)> Winter(35.80%),the maximum dissimilarity between the two groups is autumn-winter,the minimum is spring-summer.(3)Community SIMPER analysis showed that the fourth quarter may be divided into three groups,the NMDS analysis of stress values were 0.12,0.1,0.11,0.14,Similarity within the group and dissimilarity between groups had quite different.ABC curve showed in spring,fall,winter mollusk community has not been made greater interference,summer mollusc community has been made greater interference.(4)By contrasting several literature studies about Nanji Islands,concluded that in recent years,the protection of biological Nanji Islands intensified,but the intertidal mollusk species number has been reduced,and the community structure are different from before.