Abstract: We explored the niche characteristics and interspecific associations of main species in Glyptostrobus pensilis-Alnus trabeculosa community in Dongshan Village, Youxi County, Fujian Province. The abundance of plant species was investigated by adjacent lattice survey method. The results showed that the importance value (61.03%) and niche breadth (7.28) of A. trabeculosa were the largest in the tree layer, followed by G. pensilis (33.18%, 4.87). In the shrub layer, the importance value (41.16%) and niche breadth (10.31) of A. trabeculosa were the highest, followed by Hydrangea paniculata (25.51%, 6.24). Osmundastrum cinnamomeum and Mosla cavaleriei were dominant species in herb layer. In the tree layer, the niche overlap value of A. trabeculosa and G. pensilis was greater than 0.5, demonstrating a competitive relationship. In the shrub and herb layers, species pairs with niche overlap values greater than 0.5 accounted for 19.70% and 16.34% respectively, indicating interspecific competition. The overall association of tree layer (0.62) and shrub layer (0.68) showed a non-significant negative association. The herb layer (0.46) showed a significant positive association. The community was in an unstable succession stage. There was a significant negative correlation (-0.95) and strong competition between A. trabeculosa and G. pensilis. There was no seedling regeneration of G. pensilis in the shrub layer. The expansion of A. trabeculosa affected the growth of G. pensilis. Our results can provide a reference for the protection of G. pensilis and the maintenance of community stability.

Key words: Glyptostrobus pensilis, Alnus trabeculosa, importance value, niche, interspecific association