Abstract: Invasion of exotic species Ageratina adenophora into forest communities has great impacts on species diversity. Here, we examined the relationships between A. adenophora invasion and the species diversity of different forest communities in Haikou Forest Farm, Kunming City, Yunnan. Our results showed that the coverage and species abundance of native plants in the tree layer were significantly negatively related to the height and coverage of A. adenophora, and the invasion was not related to that of shrub and herb species, suggesting that the tree layer exhibited greater effects on the invasion of A. adenophora. According to the CCA, the forest communities in this area could be divided into two groups: (a) natural forests and secondary forests with less disturbance, and (b) plantation forests and secondary forests with stronger disturbance. The distance from the roads of the forests was a major factor affecting the distribution of A. adenophora. The importance value of A. adenophora showed a nonsignificant difference between the two groups. In addition, the importance value of A. adenophora was negatively correlated with the Simpson dominance index, Pielou evenness index, and Alatatlo evenness index, but was not correlated with the Shannon index. Therefore, A. adenophora’s invasion had notable impacts on the species diversity of the invaded forest communities. The primary forests had relatively high resistance to the invasion of A. adenophora, which was also related to the comprehensive characteristics of the communities, the distance from the roads, and the degree of human disturbance.

Key words: cotton, leaf senescence, maturity performance, eco-physiology, regulation.