飞机草的入侵机制—基于群落水平研究

In the process of alien plant invasion, many biological and abiotic factors in the community could resistant invaders. The community invasibility is lower with stronger resistance. The invasion of alien plants is possibly caused by the difference of community composition between native and invasive ranges, which leads to community invasibility differences. Chromolaena odorata is a noxious invasive species in the tropics and subtropics. In this study, we established a series of artificial communities with single or multiple species from different functional groups. Combination of field investigations, we want to detect (1) Is there significant difference of functional traits between native and invasive plants within a community? Does the difference lead to variance of community invasibility in two ranges? (2) Is the phylogenetic relationship significantly different between native and invasive communities? Is the difference related with community invasibility difference? (3) Is there significant difference for the effect of species interactions on community invasibility between native and invasive ranges? (4) Is there significant difference for the response of community invasibility to disturbance between native and invasive ranges. This study can identify the factors that contribute to the community invasibility differences between native and invasive ranges. It not only can improve the understanding of biological invasion mechanism, but also has a practical application value for protecting biodiversity, which can help us to manage the ecosystem effectively, and control the further inavsion of Chromolaena odorata.

在外来植物入侵过程中，群落中的许多生物及非生物因子能够抵御其入侵，抵御力越强，群落的可入侵性越低。外来植物的入侵可能是因为原产地和入侵地群落构成的差异，导致了两地群落的可入侵性不一致。本项目以外来入侵植物飞机草为实验材料，通过采用野外调查及构建人工群落的方法，来探讨：.（1）是否原产地和入侵地群落内植物的物种丰富度、功能特征、功能组多样性等存在差异？这种差异是否导致了两地群落可入侵性的差异？.（2）是否原产地和入侵地群落的系统发生存在差异？这种差异是否与两地群落可入侵性的差异有关。.（3）原产地和入侵地群落物种间的相互作用对群落可入侵性的影响是否有差异？.（4）原产地和入侵地群落的可入侵性对干扰的响应是否一致？. 通过本项目的研究，可以确定入侵地很多群落高的可入侵性的原因，对于合理有效的管理生态系统，防止飞机草的进一步入侵，保护本地生物多样性具有重要的意义。

在本项目中，我们用入侵地（中国）和原产地（墨西哥）的本地植物建由不同物种组成的人工群落，并施以活性炭和杀菌剂处理，探讨物种组成、物种丰富度、功能特征、植物和土壤微生物间的相互作用、化感物质、系统发生距离以及刈割干扰对飞机草入侵的影响。研究发现：墨西哥（原产地）物种构成的群落比中国（入侵地）物种构成的群落对飞机草的抵抗性强，并且干扰（刈割）后，中国物种构成的群落更容易被飞机草入侵；随着物种丰富度的升高，群落对飞机草入侵的抵抗能力增强；与飞机草系统发生距离远，而功能特征距离近的群落越不容易被入侵。植物和土壤微生物的相互作用，以及化感作用作用对群落可入侵性的影响具有物种专一性。 相关研究结果发表在生态学著名期刊Ecology Letters上。. 此外，我们还研究了资源波动对原产地和入侵地物种构成的群落内飞机草入侵成功率的影响。结果表明，资源波动在入侵地丰富度物种低的群落内具有显著效应；.但在物种丰富度高的群落内，资源波动效应不显著。多样性高的群落抵抗外来植物入侵的能力强，可能也是因为群落内具有某些物种利用波动资源的能力强。. 本项目的研究成果不仅具有重要的理论意义，对于飞机草的防控管理也具有重要的指导价值。借鉴该研究结果，我们构建了飞机草的防控阻截示范区，目前来看，短期（一年）防控效果较显著，长期防控效果还在继续观察中。