子午岭辽东栎群落乔木种间联结与取样面积

Interspecific association of trees species in Quercus wutaiensis communities in Ziwu Mountain related to quadrat size

以Х^2检验、种间联结系数（AC）、Person相关系数（r）、方差比率（VR）和某一取样面积尺度下的样方中未共同出现的物种对数目Na为参数，探讨黄土高原子午岭辽东栎群落主要乔木种间联结特性与取样面积的关系。Х^2检验和AC分析表明，显著的种间联结关系仅出现在25和50m^2 2个取样面积中；相关分析表明，显著的种间相关出现在取样面积25～200m^2，但r值的变化在25～100m^2较稳定；VR分析未能有效地区分不同取样面积中多物种关联的特性；Na值在面积为100～200m^2、样方数为40～80时较稳定。从合理的样方面积和适当的样方数量综合考虑，样方面积在100m^2、样方数为45个，能比较客观、稳定地反映辽东栎群落植物种间联结特性。

A series of parameters including Х^2-test, interspecific association coefficient （AC）, Person＇s correlation coefficient （r）, variance ratio （VR）, and total number of species pairs which do not exist synchronously in a given quadrat size （Na） were used to study the interspecific associations and their relationships with quadrat sizes of the dominant tree species in Quercus wutaiensis communities in Ziwu Mountain of Loess Plateau. Based on the 2 × 2 contingency table and species abundance data, the effects of different quadrat size on these parameters were examined. The Х^2-test and AC analyses showed that significant interspecific associations only appeared at the quadrat sizes of 25 mE and 50 mE. Person＇ s correlation analysis displayed that there were significant interspecific associations at the quadrat sizes from 25 to 200 m^2, and the r value changed steadily at the quadrat sizes from 25 to 100 m^2. However, VR didn＇ t disclose the overall associations of multi-species at different quadrat sizes. The fluctuation of Na was the smallest when the quadrat size was 100-200 mE and the number of quadrats was 40-80. In order to reveal the relationships between species pairs more exactly, the quadrat size should be 100 m^2, and the number of quadrats should be 45. Under such conditions, the interspecific associations of the tree species in Q. wutaiensis communities in Ziwu Mountain of Loess Plateau could be measured objectively.