北部湾北部生态系统结构与功能研究VI：浮游动物空间生态位及其分化

Abstract

根据2006-2007年北部湾北部海域4个航次调查资料，采用<em>K</em>-优势度曲线法对浮游动物种（类）群进行排序分析，运用Levins公式和Pianka指数分析了主要优势种（类）群的生态位宽度值和生态位重叠程度，并通过除趋势典范对应分析（DCCA）研究生态位分化状况。结果表明，该海区浮游动物优势种（类）群按生态位宽度值可划分为广生态位、中生态位和窄生态位三大类型。其中，广生态位的种（类）群如肥胖软箭虫、亚强次真哲水蚤、长尾类幼体等具有较强的生态适应性，生活范围较广；窄生态位的种（类）群，对环境的适应性较差，对海流和水团等环境因素的变化具有指示意义。生态位宽度能够反映种（类）群丰度季节变化，但不能反映具体丰度大小。北部湾北部全年主要优势种（类）群的生态位宽度值介于0.08-0.77之间，并且各优势种（类）群的生态位宽度差异较大，种对间生态位重叠值介于0.02-0.89之间，平均生态位重叠指数为0.45，种（类）群之间利用资源环境的互补性较强，这与海域内生境多样化并且各优势种对环境适应能力的差异存在一定联系。DCCA分析表明，影响浮游动物分布的主要因子是水深、温度和盐度，其次是叶绿素a和溶解氧。;The concept of ecological niche had remained as one of the core ideas in ecological research for almost a century, which was closely linked with interspecific competition, resource utilization had played an important role in the study of community composition and function,of the relationships among species,biodiversity,community succession and population evolution. Based on four seasonal investigations (Spring 2007, Summer 2006, Autumn 2007 and Winter 2006) in northern Beibu Gulf from 2006 to 2007, the niche breadth, niche overlap, spatial differentiation and environment effects on the abundance and spatial distribution of zooplankton were studied with qualitative and quantitative methods. The cumulative top 80% of zooplankton dominant populations were selected by the K-dominant curve method, then the niche breadths and their overlaps of zooplankton were measured using the formulas proposed by Levins Niche Breadth index and the Pianka Niche Overlap index, and the spatial niche differentiation was studied by using Detrended Canonical Correspondence Analysis (DCCA) method. The results showed that the zooplankton dominant species in northern Beibu Gulf were classified in to three groups, <em>i e.,</em> wide niche breadth groups (<em>B</em>_i=0.60-0.77), middle niche breadth groups (<em>B</em>_i=0.30-0.60), narrow niche breadth groups (<em>B</em>_i=0.08-0.30) based on the niche breadth value. The niche breadths of zooplankton such as <em>Sagitta enflata</em>, <em>Subeucalanus subcrassus</em> and Macrura larvae were wider, which was related with their own characteristics and the capability of adapting environment, while the species whose niche breadths were narrower such as <em>Doliolum denticulatum</em> and <em>Dolioletta gegenbauri</em> will be considered as an indicative significance for ocean currents and water masses. Niche breadth could reflect the zooplankton abundance with the seasonal dynamic changes,and also could objectively reflect the species in the habitat in which the distributions of degree but it could not reflect the Accurate zooplankton abundance. The niche breadth values of dominance zooplankton species ranged between 0.08 and 0.77 in the whole year and The niche breadth difference among the dominant populations was great; The niche overlap values of dominance zooplankton species ranged between 0.02 and 0.89 in the whole year and the average niche overlap index was 0.45, there was strong complementarity in terms of the utility of resource among zooplankton populations, which had certain relationship with northern Beibu Gulf habitat diversification and the strong complementarity in terms of the utility of resource among zooplankton populations. The Detrended Canonical Correspondence Analysis result showed that depth, temperature and salinity had more important influence on the species spatial distribution than Chlorophyll a and dissolved oxygen.