Analysis on the Ecological Niche and Interspecific Linkage of Dominant Species in the Shrub Layer of Casuarina Equisetifolia Community in Pingtan Island
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 the x2 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 the x2 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.
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