外来植物入侵力主要理论与展望

外来植物入侵是全球性环境问题.我国植物入侵态势严峻,随着全球化的提速,这一威胁将加剧.总结外来种入侵力的主要理论,分析其生态学机制、常见的理解误区,剖析入侵力的主要表现形式和产生的机制,可为进一步明确未来研究方向,提高预测、预警、预防和治理工作效率提供参考.通过总结分析发现:理论间存在部分包含、支持、相悖等逻辑关系,并且生态位在外来种和土著种之间的差异应该只是外来种定殖的一个有利条件.新的认知是,适合度优势才是入侵种竞争排斥土著种的必须条件,因而是入侵植物获得成功的重要原因.适合度优势表现为快速生长等一些有利于竞争、扩散的性状稳定遗传.适合度优势产生于生理、生化、解剖、形态等方面的优势,而这些优势来自选择压力变化后外来种的进化或基因型的保留.这些研究进展说明,外来植物入侵力产生的机制是多样化的.因此,除去发现其他入侵力机制进而丰富完善入侵力理论体系外,利用数据综合分析等手段,总结我国外来植物入侵力组成的主要性状,从而为构建外来植物入侵风险评价体系提供直接依据,指导海关等相关部门的检查检疫工作,是降低我国入侵植物威胁的有效方法之一.

Main theories and prospects of alien plant invasiveness

Background, aim, and scope Invasions of alien plants have caused severe ecological, economic and social consequences. China is heavily invaded by an array of alien plants, so to identify the forms of invasiveness and the potential mechanisms of alien plant invasion success is important for the invasive risk evaluation, invasive spread forecast, and control of invasion. Materials and methods Nine theories that describe plant invasiveness and new findings are analysed to illustrate the frameworks of these theories and the relationship among these theories. Results The relationship among the theories includes partial support or contrary. Strikingly, the difference of niches between alien and native species could only facilitate the colonization of alien species, and the superiority of fitness that alien species show might be the essential condition for the competitive exclusion of native species by alien species. The superiority of fitness is the trait that facilitates the spread and interspecific competition of alien species. Discussion The superiority of fitness may often derive from the advantages of physiological, biochemical, anatomical and morphological traits. Moreover, these advantages should be the results of the rapid evolution and conservation of certain genotypes of alien species after the alteration of selective pressure. Conclusions The difference of niches between alien and native species is not be the only factor that influences alien plant invasion success, and such factors should be diverse. Recommendations and perspectives Besides the findings of new mechanisms, reviewing the main source of invasiveness by meta-analysis can be one of the effective measures for decreasing the threats of alien plants in China.