平潭岛木麻黄群落灌木层优势物种生态位及种间联结分析

Analysis on the Ecological Niche and Interspecific Linkage of Dominant Species in the Shrub Layer of Casuarina Equisetifolia Community in Pingtan Island

为探究平潭岛木麻黄群落灌木层优势物种的种间关系及群落发展状态,基于群落调查数据,通过生态位特征计算和种间联结分析,结果表明:(1)灌木层植物共计56种,重要值和生态位宽度最大的为木麻黄;生态位宽度并不完全与物种重要值大小变化一致,还可能与频度有关。(2)有43.8%的种对不产生生态位重叠,优势物种间的生态位重叠程度普遍较低;生态位宽度较小的物种也存在与其他物种产生较大的生态重叠现象。(3)灌木层优势物种的总体联结性呈不显著负联结。(4)χ2检验、Pearson相关检验和Spearman秩相关检验结果均表明种间关联程度较弱,种间联结较松散;AC值比χ2检验增加了联结显著率,但是也夸大了联结性的强度,导致出现极显著负联结种对数过高的现象。平潭岛木麻黄灌木层群落处于不稳定的演替阶段,亟需加强其群落稳定性的构建和植被修复保护的相关工作。

In order to explore the interspecific relationships and community development status of dominant species in the shrub layer of the Casuarina equisetifolia community in Pingtan Island,based on community survey data,through niche characteristic calculation and interspecific linkage analysis,the results show that:(1)There are 56 species of shrub layer plants.The species with the largest important value and niche width is Casuarina equisetifolia.Niche width is not completely consistent with the changes in the importance value of the species,and may also be related to frequency.(2)43.8%of species pairs do not have niche overlap,and the degree of niche overlap among dominant species in the shrub layer is generally low;plants with smaller niche widths also have greater niche overlap with other species.(3)The overall connectivity of dominant species in the shrub layer showed an insignificant negative connection.(4)The results of theχ2 test,Pearson correlation test and Spearman rank correlation test all show that the degree of interspecific correlation is weak and the interspecific connection is loose;the AC value increases the significance rate of the connection compared with theχ2 test,but it also exaggerates the strength of the connection.This leads to the phenomenon that the logarithm of extremely significant negative link species is too high.The Casuarina equisetifolia shrub community on Pingtan Island is in an unstable succession stage,and it is urgent to strengthen the construction of community stability and vegetation restoration and protection.