鄱阳湖洲滩优势植物种群的分布格局

Patterns of dominant populations of plants in Islets of Poyan Lake

根据野外样地调查数据,应用方差均值比率法、聚集强度指数法和相关分析法,对鄱阳湖洲滩优势植物种群分布格局进行了研究,分析了其形成的原因,并比较了各指数间的关系。结果表明,鄱阳湖洲滩优势植物种群都为聚集分布,它们的聚集强度存在差异,聚集度最高的是糙叶苔草(Carex scabrifolia),最小的是稻槎菜(Lapsana apogonoides),以根茎繁殖的多年生植物的聚集度要高于以种子繁殖的一年生植物;在空间上,洲滩植物种沿水分梯度呈现有规律的分布,与湿地土壤的沉积类型也有一定关系;湿地植物的克隆繁殖特性和对水分梯度的依赖性是种群分布格局形成的主要原因。

Based on the data from the fields,the patterns of dominant populations of plants in islets of Poyang Lake were investigated by using dispersal index ratio method,canonical correspondence analysis method and clump intensity indexes（the intensity index k of negative binomial distribution,clump intensity,Cassie index,patchiness index and mean crowding）.The cause involved with the pattern was analyzed and the relationship between these indexes was surveyed by their correlation coefficients.The results showed that the patterns of those populations were all clumped but apparently different in clump intensity,while Carex scabrifolia has the highest and Lapsana apogonoides has the lowest clump intensity respectively,the clump intensity of perennial plants with rhizome propagation was greater than that of the annual species with seed propagation.Moreover,there was a relationship to some extent between the regular distribution pattern of wetland vegetation in islets of Poyang Lake along water gradient and depositional types of wetland soils.The characteristic of clone reproduction and the dependence of water gradient could be explained for the formation of distribution patterns of islet plants.