土壤养分条件影响典型菊科外来种入侵能力的作用机制

土壤养分条件(低或高)是影响外来植物入侵能力的一个重要因素。虽然研究常发现入侵种在土壤养分条件增加时生物量比本地种增加的更多，但除此之外，人们对这一问题的认识显得不够全面和深入，以下问题仍有待回答：竞争可否改变土壤养分条件对植物入侵能力的影响？入侵种在一定土壤养分条件下的快速生长是否以降低其对生物量损失的耐受性为代价？入侵种是否在不同土壤养分条件下均可与土壤形成相对于本地种更正面的反馈作用？土壤养分条件对入侵和本地种种子性状的影响是什么？本项目计划在不同土壤养分条件下，通过对比四种菊科入侵种和三种生活型相似且伴生的本地菊科植物在（1）单独生长、两两竞争时的生物量和功能性状，（2）受到干扰后的生长和竞争能力，（3）与土壤间的反馈作用，（4）产生的种子性状及其生态适应性这四方面的差异，来回答上述科学问题。研究结果可系统的揭示土壤养分条件影响植物入侵能力的作用机制，并为控制外来杂草提供科学依据。

Soil nutrient conditions (low or high) are an important factor affecting the invasion capacity of exotic plants. However, human knowledge on this issue appears to be not comprehensive and thorough despite the fact that research commonly finds that invasive species increase their biomass more than natives as soil nutrient availability increases, and the following questions remain to be answered: can competition change the effects of soil nutrient conditions on plant invasion capacity? Does the fast growth rate of invasive species under certain nutrient conditions come at the cost of a reduced tolerance to biomass losses? Can invasive species generate more positive feedbacks with soil than natives across different soil nutrient conditions? What are the influences of soil nutrient conditions on seed traits of invasive and native species? Under different soil nutrient conditions and by comparing the differences between four invasive species of Asteraceae and three co-occuring native plants of Asteraceae with similar life form in (1) the biomass and functional traits when grown alone or in pairwise competition, (2) the growth and competitive ability when subject to disturbance, (3) the feedbacks with soil, and (4) the traits of the seeds produced and the ecological adaptability of these seeds, this project plans to answer the aforementioned scientific questions. Research results can systematically reveal the mechanisms underlying the effects of soil nutrient conditions on plant invasion capacity, and provide a scientific foundation for controlling exotic weeds.