四川攀西地区云南松群落物种多样性和谱系多样性对紫茎泽兰入侵的影响

外来植物入侵严重威胁着入侵地本土植物多样性和生态系统功能, 认识外来物种的入侵机制有助于提高对入侵植物的防控能力。本文以攀西地区云南松(Pinus yunnanensis)林下外来入侵植物紫茎泽兰(Ageratina adenophora)为研究对象, 基于大量野外群落调查, 从群落可入侵性入手, 分析了环境因子和群落物种多样性、谱系多样性等群落生态学特征对紫茎泽兰入侵的影响。结果表明: 海拔、坡向和火烧强度等环境因子和冠层郁闭度、灌木层盖度等生物因子对研究区紫茎泽兰入侵强度没有显著影响(P > 0.05); 但群落灌木层物种多样性和草本层组分种与紫茎泽兰的亲缘关系显著影响紫茎泽兰的入侵强度(P < 0.05), 说明灌木层对光照等环境资源的占用和草本层(同层)物种对相似资源的竞争能够在很大程度上抑制紫茎泽兰的入侵。

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

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 of herb 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.