外来植物对我国城市生态系统的影响

外来植物在我国城市园林绿化中起到了重要作用，但在生态与环境保护方面也带来了一些严重问题。本文在简要分析城市植被系统单一性与脆弱性特征的基础上，探讨了外来植物对城市生态系统中土壤理化性状与含水量的影响；分析了在外来植物作用下，城市植物群落结构变化与逆向演替的原因，城市生态系统中物种多样性与生态系统多样性下降原因和遗传多样性改变机理。最后从外来植物生物学特性与适应性以及环境和人为因素这几个方面分析了外来植物种群形成乃至成灾的机制。

The influence of exotic plants on the China city ecosystem

Exotic plants have undoubtedly played important roles in the city forestation and grassing. However, they have also brought serous problems for the protection of the city ecology and environment. Based on the analyses of the scarcity and vulner ability of the city vegetation system, the influence of exotic plants to the soil physical and chemical property and soil moisture content in the city ecosystem, the mechanism of the structure transformation and regressive succession of city plant communities, the mechanism of decreasing of the diversity of species and ecosystems, and the transformation mechanism of genetic diversity in city ecosystem were are analyzed. Lastly, the mechanism of the founding and wild proliferation of exotic plant populations was discussed considering the biological characteristics and adaptation capacity of exotic plants, as well as some environmental and artificial factors.