Abstract: We examined the niche characteristics and interspecific covariant relationship of main species in Phyllostachys edulis-Alsophila spinulosa association in Chishui A. spinulosa National Nature Reserve under P. edulis disturbance condition, and analyzed the mechanism of competition and coexistence across different species. The results showed that there were 67 species from 53 genera and 40 families in the association. The importance values, Shannon niche breadth index (B_S), and Levins niche breadth index (B_L) of P. edulis were the largest, indicating its absolute dominant status in association. The importance value and B_L of A. spinulosa ranked the second, while B_S was the third. There were 190 pairs of 20 main species. The niche overlap between P. edulis and A. spinulosa was the largest, with niche overlap value of 0.64. 71.6% of species pairs had niche overlap of less than 0.2, indicating low niche overlap and high degree of niche differentiation among species. The overall association of main species in association was significantly positive, and the community was relatively stable. The correlation among the main species was not significant, the linkage was not strong, and the species were independent from each other. P. edulis showed significant positive correlation with A. spinulosa, Brassaiopsis glomerulata, Ficus virens, and Mallotus barbatus, while P. edulis showed significant negative correlation with Mallotus philippensis, Cinnamomum glanduliferum, and Machilus gamblei. Niche difference and fitness between P. edulis and natives affected the coexistence and competition among species. Controlling the expansion of P. edulis and limiting the size of species with negative correlation with A. spinulosa could create a favorable living environment for A. spinulosa.

Key words: Phyllostachys edulis invasion, Alsophila spinulosa, niche, interspecific association.