外来种互花米草入侵模式与爆发机制

互花米草（Spartina alterniflora Loisel）因其促淤造陆和消浪护堤作用显著而被许多国家引种，如今却在侵入地快速蔓延并呈现爆发趋势，对生态系统造成了极大危害，被认为是研究生物入侵生态学和遗传学的模式植物。从种群的入侵力、生态系统可入侵性和入侵通道3个方面探讨互花米草的爆发机制，研究结果表明高遗传分化和基因渗入能力是互花米草爆发的遗传基础，对逆境的高抗性和强竞争力是其快速扩张的保障，而高繁殖系数是互花米草爆发的源泉。我国互花米草种群的早期扩散人为影响超过了自然过程，快速扩张呈现出点源扩散和多点爆发的特点，从而为其种群控制带来困难，同时种子的跳跃式和连续式扩散在互花米草种群维持、更新和爆发中有重要作用，强有力的克隆生长能力也为互花米草种群的连续扩张提供了保障。现阶段要完全控制和根除互花米草是不实际的，但在及时预测预警的基础上，应用成本一效益分析方法，采取有序控制和综合开发利用的策略，仍可望妥善解决互花米草入侵所带来的负面效应。

Preliminary studies on invasive model and outbreak mechanism of exotic species, Spartiona alterniflora Loisel.

The invasive species, Spartina alterniflora Loisel., has been introduced to many countries because it accelerates sediment accretion and therefore can act as a seawall. However, the exceptional adaptability and reproductive ability of this species has led to its extensive dispersal into habitats where it has negative impacts on native species. Previous researchers have shown Allee effects in the establishment of S. alterniflora, in part due to inbreeding depression and rapid local adaptation, making this species a model plant for studying biological invasion from ecological and genetic perspectives. In China, the expansion of S. alterniflora, based on intentionally transplanted in multiple loci, has developed an understanding of the mode of point-source dispersal, suggesting multi-locus outbreaks and weak Allee effects. The episodic and continuous dispersal pattern of seeds plays an important role in maintaining, recruitment and expansion of S. alterniflora populations. Furthermore, expansion of S. alterniflora populations is also enhanced by clonal growth. It has proven very difficult to eradicate S. alterniflora, but timely monitoring combined with a clear understanding of the factors that promote invasion may alleviate the effect of this species in natural habitats.