Biological invasions are determined by interactions between resident plant communities and exotic plants. Time of invasion and species diversity of resident plant communities may greatly affect exotic plant invasions. We assembled low‐ and high‐diversity resident plant communities by sowing seeds of four and eight grassland species, respectively, and at each of three time periods (1, 4 and 7 weeks after sowing), the resident communities were invaded by Hydrocotyle vulgaris or not. We also constructed a plant community with H. vulgaris alone. Presence of H. vulgaris had no effect on biomass of the resident communities or biomass of each component species. Community age significantly affected biomass and evenness of the resident communities, and their competition with H. vulgaris, but the priority effect of the resident communities was slight. Increasing species richness did not change the interaction between H. vulgaris and the resident plant communities. These findings suggest a weaker competitive exclusionary effect of H. vulgaris on the resident communities with early germination, and H. vulgaris tended to have no significant impact on intact resident terrestrial plant communities. Thus, the potential risk of H. vulgaris invasion is low, especially in the communities with young age.

中文翻译：

---

外来植物寻常型水藻的生长特性和常驻植物群落的均匀性是由群落年龄而不是物种多样性来介导的

生物入侵取决于常驻植物群落与外来植物之间的相互作用。入侵时间和常驻植物群落的物种多样性可能极大地影响外来植物的入侵。我们通过播种的分别四个和八个草原物种，种子组装低和高多样性居民植物群落，并且在每个的三个时间段（1,4和播种后7周），驻地社区被入侵野天胡荽或不。我们还建立了一个仅由寻常型嗜血​​杆菌组成的植物群落。寻常型嗜血​​杆菌的存在对居民区的生物量或每个组成物种的生物量没有影响。社区年龄显着影响了居住社区的生物量和均匀度，以及它们与普通居群的竞争，但居住社区的优先作用很小。物种丰富度的增加并未改变寻常型嗜血​​杆菌与常驻植物群落之间的相互作用。这些发现表明，普通芽孢杆菌对萌发较早的常居群落的竞争排斥作用较弱，而普通常杆菌对完整的常驻陆生植物群落没有明显影响。因此，寻常型嗜血​​杆菌的潜在风险 入侵率低，尤其是在年轻的社区中。