秦岭金水河岸弃耕地草本植物种间关系

Interspecific Relationships among the Herbage Species of Abandoned Farmlands alongside Jinshui River in the Qinling Mountains

基于野外51个样方调查数据,运用2×2列联表的Fisher精确检验、Pearson相关系数和Spearman秩相关系数检验,并结合DCA排序,研究了秦岭金水河岸弃耕地40种草本植物的种间关系。结果表明,Spearman秩相关系数检验,有90个种对存在显著相关(p<0.05或p<0.01),其中负相关9对,占所有种对数的1.15%,正相关81对,占所有种对数的10.38%;Pearson相关系数检验有55个种对呈显著正相关,2个种对呈显著负相关;Fisher精确检验表明28个种对呈显著正关联,5个种对呈显著负关联。根据DCA排序将40种草本植物划分为3个生态种组,代表着不同的演替阶段,反映了随着环境条件变化植物群落组成发生的相应变化。对资源和环境要求类似的种对倾向于表现出显著的正相关,负相关的种对多处于不同演替阶段。

Based on the field data collected from 51 plots on abandoned farmlands alongside Jinshui River in the Qinling Mountains, the interspecific relationships among the 40 main herbage species were studied using Fisher＇s exact test for 2 × 2 contingency tables, Pearson＇s correlation coefficient and Spearman＇s rank correlation coefficient test, coupled with DCA ordination. According to Spearman＇s rank correlation coefficient,90 species-pairs had significant （p 〈0. 05 or p 〈 0. 01 ） correlation, including 9 negative correlation species-pairs and 81 positive correlation species-pairs,accounting for 1.15%, 10.38% in the total 780 species-pairs, respectively. In the Pearson＇s correlation coefficient test, the number of speciespairs being significantly positive was 55 while the negative was 2. In addition, positive association coefficients of 28 species-pairs and negative association coefficients of 5 species-pairs for the Fisher＇s exact test were significant. Forty species were classified into three ecological species groups in the ordination space representing different succession stages, and the variation in species along the first DCA axis represented the species turnover along the succession and environment gradient. The species-pairs with the similar environment and resources requirement tended to display positive correlation, while the negative correlation species-pairs always occurred in different succession stages.