鄱阳湖湿地典型草洲主要植物种群在5个资源环境梯度上的生态位特征

Niches of the Major Plant Populations in Grasslands Typical of the Poyang Lake Wetland in Five Resources-Environmental Gradients

基于鄱阳湖典型湿地恒湖农场茶叶港草洲19个样地(5 m×5 m)95个样方(1 m×1 m)实地调查得到的10种主要植物和高程、土壤pH值、电导率、含水量、有机质含量5个资源环境数据,采用Levins生态位宽度指数和Pianka生态位重叠指数,研究植物种群生态位宽度与重叠度。结果表明:(1)在5个资源环境梯度上,优势种灰化薹草(Carex cinerascens)和虉草(Phalaris arundinacea)生态位宽度较大,群落偶见种旋鳞莎草(Cyperus michelianus)、广州菜(Rorippa cantoniensis)和芦苇(Phragmites australis)等生态位宽度相对较小;(2)10种主要植物生态位重叠值普遍较小,但也存在例外,主要表现在刚毛荸荠(Eleocharis valleculosa)、旋鳞莎草和广州菜3者之间的生态位重叠值相比其他物种对要高;(3)10种主要植物种群生态位宽度均与物种重要值呈显著(P<0.05)或极显著(P<0.01)正相关关系,而与物种重要值变异系数呈极显著负相关关系(P<0.01)。恒湖农场茶叶港草洲10种主要植物对资源环境的利用能力和适应性差异较大,其生态位重叠值普遍较小,物种重要值是影响生态位宽度的重要因素。

Data of 10 dominant plant species and 5 resources-environmental factors（elevation,soil pH,electrical conductivity,water content and organic matter content） were gathered through surveys of 95 quadrates（1 m×1 m） in 19 sample plots（5 m×5 m） in the Chayegang Grassland of the Henghu Farm,typical of the Poyang Lake wetland,and analyzed for breadths and overlaps of the ecological niches of the plant populations,using the indices of Levins niche breadth and Pianka niche overlap.Results show that：（1） Carex cinerascens and Phalaris arundinacea are the dominant species in the region and have broader niche along the five resources-environmental gradients,while Cyperus michelianus,Rorippa cantoniensis,Phragmites australis and some others are accidental species and have relatively narrow niches;（2） The 10 plant species rarely overlap in niche,but exception exists with Eleocharis valleculosa,Cyperus michelianus and Rorippa cantoniensis,which overlap each other much more than the other plant species pairs;（3） Of the 10 major plant populations,niche breadth is significantly（P0.05） or extra-significantly（P0.01） and positively related to other important values,but extra-significantly（P0.01） and negatively related to variation coefficient of their important values.The 10 dominant plant species vary sharply in resource-environment utilization capability and adaptability to the 5 environmental factors,and are generally low in niche overlap.Importance values of the plant species are the major factors dictating niche breadth.