反枝苋群落优势种的种间关联性分析

根据野外95个样方的调查数据，运用2×2列联表的χ₂检验、Jaccard关联指数、Pearson相关系数和Spearman秩相关系数对山西省中南部地区反枝苋群落的25个优势种，共300个种对的种间关联性和相关性进行分析。研究结果表明:1)群落总体呈负相关趋势，优势种的分布相对独立，群落结构较为松散，显著和极显著关联的种对较少；2）χ₂检验与关联度指数有机结合才能更为准确的反映种间关系；3）Spearman秩相关系数灵敏度高，分析结果较χ₂检验与Pearson相关系数更为合理准确；4）根据25个优势种对环境的适应方式和主导生态因素结合PCA排序，将它们划分为4个生态种组，各生态种组内的种对具有相同的资源利用方式和生态要求。

Interspecific Association of Dominant Species of Amaranthus retroflexus L. Community

Based on the data of 95 plots obtained from investigation, by using χ₂-test for 2×2 contingency table, Pearson coefficient and Spearman rank coefficient, the interspecific association and correlation among 300 species-pairs of 25 dominant plant species of Amaranthus retroflexus L. community in Shanxi were analyzed. The results indicated that: 1)The plant community was negative association, the structure of the community was scattered, few species pairs showed significant or highly significant association. 2)Only combine χ₂-test with correlation index can reflect the interspecific relationship more accurately. 3)Spearman rank correlation coefficient was more sensitive. Compared with χ₂-test and Pearson correlation coefficient, the result of the Spearman rank correlation coefficient was more reasonable. 4)According to the adaptability to the environment and the relationships between plants and environment, 25 species were divided into four ecological species groups, with the same resource utilization ways and ecological requirements of the species in each group.