Data from: Contrasting effects of phylogenetic relatedness on plant invader success in experimental grassland communities

1. Identifying the factors determining the success of invasive species is critical for management of biological invasions. Darwin's naturalization conundrum states that exotic species closely related to natives should be successful because of a shared affinity for local environmental conditions, but at the same time close relatives often compete more intensively, limiting ‘niche’ opportunities for the invaders. Previous studies have generally considered these two ‘opposing’ hypotheses as mutually exclusive, yet evidence for both of them abounds, indicating a practical dilemma for management of biological invasions. 2. In this study, we sowed the seeds of the invasive exotic Ambrosia artemisiifolia L. into 369 experimental plant communities to mimic an introduction of the exotics into a series of new habitats. We further linked the establishment and growth performance of the invader in these experimental communities to the phylogenetic relatedness between the invader and the community residents where it was introduced. 3. We found that the probability of invader establishment declined with increasing phylogenetic distance between the invader and residents, whereas the average size of surviving invader individuals increased with the phylogenetic distance. 4. These results can be at least partly explained by the observations that close relatives tend to create similar soil microhabitat through harboring similar soil enzymes (e.g. alkaline and acid phosphatases) benefiting invader establishment, and that intense competitive interactions between the invader and its close relatives suppressed exotic growth. 5. Synthesis and applications. This study presents the first experimental evidence that phylogenetic relatedness has contrasting effects on different aspects of invader success, thus shedding light on the long-standing Darwin's naturalization conundrum. Moreover, our findings also have important implications for management of plant invasions: for controlling invasive species characterized by high establishment probability, native species distantly related to the invasive species can be planted in sites surrounding the invasion foci; whereas, the opposite seems to be true for controlling those characterized by large individual size.

1. 明确决定入侵物种成功的关键因素，对于生物入侵防控工作至关重要。达尔文归化悖论（Darwin's naturalization conundrum）指出，与本地物种亲缘关系相近的外来物种，因适配当地环境条件的共性更易成功定殖；但与此同时，近缘物种间的竞争往往更为激烈，会压缩入侵者的生态位空间。过往研究通常将这两种“对立”假说视为互斥关系，但两者均有大量证据支持，这也为生物入侵管理带来了现实困境。2. 本研究将入侵外来物种豚草（Ambrosia artemisiifolia L.）的种子播种至369个实验植物群落中，以模拟外来物种向一系列新生境的入侵过程。进一步将入侵者在这些实验群落中的定殖与生长表现，与其引入群落中本地物种的系统发育亲缘关系进行关联分析。3. 研究结果显示，入侵者与本地物种间的系统发育距离越大，其定殖概率越低；而存活入侵者个体的平均体型则随系统发育距离的增大而升高。4. 上述结果至少可部分通过以下观测得到解释：近缘物种往往通过分泌相似的土壤酶（如碱性磷酸酶与酸性磷酸酶）构建相似的土壤微生境，从而利于入侵者定殖；而入侵者与其近缘物种间的激烈种间竞争，则会抑制外来物种的生长。5. 综合与应用。本研究首次通过实验证实，系统发育亲缘关系对入侵成功的不同维度具有截然相反的调控效应，从而为长期存在的达尔文归化悖论提供了实验依据。此外，本研究结果对植物入侵防控亦具有重要指导意义：针对定殖概率较高的入侵物种，可在入侵焦点区域周边种植与该入侵物种亲缘关系较远的本地物种；而对于以个体体型大为特征的入侵物种，则可采取相反的防控策略。