Effects of taxonomic and phylogenetic diversity of resident Pinus yunnanensis communities on Ageratina adenophora invasion in the Panxi region, Sichuan Province

Abstract

Aim: Alien plant invasion seriously threatens diversity of native plants and ecosystem function. Understanding the underlying mechanisms of plant invasion could help to prevent and control alien plant invasion. Methods: In this study, we selected Ageratina adenophora, an invasive herb invaded in Pinus yunnanensis communities in Panxi region of China, as target species. Based on field investigation, we assessed the effects of environmental factors and community characteristics such as species diversity and phylogenetic diversity on the invasion of A. adenophora. Results: We found that neither environmental factors (i.e. altitude, slope, and fire severity) nor biological factors (i.e. canopy closure and shrub coverage) have significant effect on the intensity of A. adenophora invasion. However, our results demonstrate that the invasion intensity of A. adenophora was significantly impacted by the species diversity of shrub layer (P < 0.05) and the net relatedness index of herb layer to A. adenophora (P < 0.05). Conclusion: The communities with higher species diversity of shrub layer and more closely related to A. adenophora ofherb layer were less likely to be invaded, indicating that A. adenophora invasion could be inhibited by competition for light with shrubs, and also be inhibited by competition for nutrition and occupation with its closely relatives.