红树林区软体动物生态位的三种分析方法

利用广东湛江红树林保护区定量取样获取的软体动物密度数据，根据Shannon-Wiener和Pj．anka公式，分别选用潮带和季节（方法1）、红树植物群落和季节（方法2）、红树植物群落和潮带（方法3）3种不同环境因子组合确定环境资源位点数，从而计算研究区软体动物生态位宽度和物种间重叠值。结果表明，3种分析方法计算结果有差别，采用方法1、方法2和方法3计算的物种生态位宽度分别为0～1．96、0～2．16、0～1．64；生态位重叠指数为0～0．1的种对，方法1、方法2和方法3分别占25．1％、32．8％和21．6％，生态位重叠指数为0．1～0．5的种对，分别占31．6％、36．2％和22．3％，生态位重叠指数〉0．5的种对分别占43．396、3196和56．1％。可见，方法3计算出的生态位重叠指数比其它2种方法的大。物种聚类和排序也验证了3种分析方法的计算结果有差别。将计算结果与实际定量取样比较，表明以红树植物群落和季节为准确定环境资源位点数的分析方法与实际相符，适合红树林区软体动物的生态位研究。

Three methods of niche analysis on mollusk in mangrove area

Based on the mollusk density data from quantitative sampling,and choosing tidal flat and season(method 1),mangrove and season(method 2),and mangrove and tidal flat(method 3) as the combinations of environmental factors to decide the spot number of environmental resources,this paper calculated the niche breadth and niche overlap of mollusk species in Zhanjiang Mangrove Nature Reserve by using Shannon-Wiener and Pianka formula.The results showed that the niche breadth of the mollusk species calculated by the methods 1,2 and 3 was 0-1.96,0-2.16 and 0-1.64,and the niche overlap at 0-0.1,0.1-0.5 and > 0.5 among the species accounted for 25.1%,32.8% and 21.6%,31.6%,36.2% and 22.3%,and 43.3%,31% and 56.1%,respectively,suggesting that the niche overlap calculated by method 3 was bigger than that by other two methods.The hierarchical cluster dendrogram and MDS ordinal configuration of mollusk species also verified the difference of the three methods.Comparing the calculated results with actual quantitative sampling data,the analysis method of using mangrove and season to decide the spot number of environmental resources was in accordance with the reality,which was feasible for the niche study of mollusk in mangrove area.