Abstract: Conyza sumatrensis is an exotic species in China, and it has affected the biodiversity, composition, structure and stability of native communities. The interspecific association of 12 primary species in native community invaded by C. sumatrensis and its’ stability were analyzed by Variance ratio, χ2 test and Jaccard index based on 2×2 contingency table and improved Godron M.’s measure, in the area of Shangrao City. The results showed that: (1) The whole native community not invaded by C. sumatrensis appears positive association. There are lots of positive association species-pairs, and also exist highly significant positive association species-pairs in the community. (2) The whole native community invaded by C. sumatrensis appears negative association, and significant negative association species-pairs appear in the community. The number of positive association species-pairs reduces sharply compared with before this, and lots of significant positive association species-pairs disappear. The competition of species increases in the invaded native community, and some species can not exist stably in disadvantage niche because of their weak competition. (3) Some species with close relation in local community are divided into two different ecological groups after C. sumatrensis invaded. (4) The stability of the native community reduces because of C. sumatrensis’s attack, 16 species in native community disappear gradually and 4 new species appear.

Key words: Conyza sumatrensis, interspecific association, χ2 test, Jaccard index, community stability

摘要： 根据2×2列联表，运用方差比率（VR），χ2检验和Jaccard指数以及改良的Godron M.稳定性测度方法，研究江西省上饶市苏门白酒草群落中12个主要种群间的联结性。结果表明：(1)苏门白酒草入侵前群落总体联结性为显著正联结，群落中的正联结种对多，存在极显著正联结种对；(2)苏门白酒草入侵后，群落总体种间联结性呈负相关，种对正联结数量较入侵前明显减少，出现显著负联结种对；(3)苏门白酒草入侵后，联结性较强的乡土群落植物明显分为两个生态种组；(4)苏门白酒草的入侵导致乡土植物群落稳定性下降，16个原有物种消失，出现4个新物种。

关键词: 苏门白酒草, 种间联结性, χ2检验, Jaccard指数, 群落稳定性