珍稀濒危植物江南油杉群落乔木层主要树种种间关联性分析

Interspecific Association Analysis of Dominant Tree Species of Rare and Endangered Plant in Keteleeria fortunei var. cyclolepis Community

摘要:

基于2×2列联表，采用方差比率法（R_v）、x²检验、Pearson相关系数检验和Spearman秩相关系数检验等方法，对福建君子峰国家级自然保护区江南油杉（Keteleeria fortunei var. cyclolepis）群落乔木层主要树种进行种间关联性分析，并通过主成分分析（PCA）划分生态种组。结果表明，21种主要树种总体表现为不显著负关联，且江南油杉与其他物种多呈不显著相关。210个种对中，正相关的有110对，负相关的有81对，不相关的有19对，正负比1.36。绝大多数种对间呈不显著相关，显著率仅为0.48%，物种间相互独立。Pearson相关系数和Spearman秩相关系数检验结果具有一致性，负相关种对数大于正相关种对数，绝大多数种对不显著，显著率分别为6.19%和7.14%。与x²检验相比，Pearson相关系数和Spearman秩相关系数检验方式更加灵敏。运用PCA二维排序可将主要树种划分为4个生态种组，同一生态种组内物种的生态习性和资源需求相似，多呈正相关，种对间相互依赖共存；不同生态种组间物种多呈负相关，种对间相互竞争。江南油杉群落乔木层主要树种的种间关联性较为松散，大多数物种为独立分布，幼苗存在更新障碍，且幼树个体竞争压力较大，种群规模呈逐渐缩小的趋势。为促进江南油杉种群正常生长与更新，应对江南油杉幼苗进行重点保护。

Abstract:

The correlations of dominant tree species of Keteleeria fortunei var. cyclolepis community in Junzifeng Nature Reserve, Fujian Province were analyzed by using 2×2 contingency table, variance ratio (R_v), x²-test, Pearson correlation coefficient test and Spearman rank correlation coefficient test, and the ecological species groups were divided based on principal component analysis (PCA). The results showed that there was not significant negative correlations existed among the 21 dominant tree species, and Keteleeria fortunei var. cyclolepis had not significant association with other species. Among 210 species pairs, 110 species pairs were positively correlated, 81 species pairs were negatively correlated, and 19 species pairs were unrelated, with a positive-negative ratio of 1.36. Most species pairs were not significantly correlated each other, and the significantly correlated rate was only 0.48%. The results of Pearson and Spearman rank correlation coefficient test were similar. The number of negative correlation species pairs was greater than that of positive correlation species pairs, and most species pairs were not significantly, and the significantly rates were 6.19% and 7.14%, respectively. Compared with x²-test, the other two test were more sensitive. The dominant tree species could be divided into four ecological species groups by PCA two-dimensional sequence. The ecological habits and resource requirements of species in the same group were similar, most of them were positively correlated, and interde-pendence coexisted. There was a negative correlation among species in different ecological species groups, and species pairs competed with each other. The interspecific association of dominant tree species of Keteleeria fortunei var. cyclolepis community was relatively non-significant, and most species were independently distributed. The seedlings were difficult to renew, saplings face greater competitive pressure, and population size is gradually shrinking trend. In order to promote the normal growth and regeneration of Keteleeria fortunei var. cyclolepis population, the seedlings should be protected.