We conducted a mesocosm restoration experiment to test the efficacy of early summer sowing of seed mixtures for inhibiting the emergence, growth and/or survival of giant hogweed (Heracleum mantegazzianum) seedlings. H. mantegazzianum is invasive in Europe and North America, where it has a negative effect on plant diversity and represents a serious health hazard, due to the photodermatitis it may cause. We tested five plant mixtures comprising a selection of North American native or naturalized non-invasive plant species. Compared to the unseeded control mesocosm, all plant covers reduced seedling emergence, growth and survival of H. mantegazzianum. There were large differences between mixtures regarding inhibition effects. The nature of the effects depended on species composition, with one mixture more effective in preventing establishment, another essentially affecting seedling growth and survival. Total plant cover, irrespective of seed mixtures, appeared to have a major effect on H. mantegazzianum. Other factors that may have played a role included the litter from the seeded plants and the allelopathic effect of Canada goldenrod (Solidago canadensis). Our study adds to the growing body of evidence promoting the restoration of a plant cover as a means to prevent reinfestation by invasive species following a control operation.

我们进行了介观恢复实验，以测试初夏播种的种子混合物对抑制巨型猪草（Heracleum mantegazzianum）幼苗的出现，生长和/或存活的功效。Mantegazzianum H. mantegazzianum在欧洲和北美洲具有入侵性，对植物多样性有负面影响，并且由于其可能引起的光皮炎，对健康构成严重危害。我们测试了五种植物混合物，其中包括精选的北美本地或自然化非入侵植物物种。与未播种的对照包膜相比，所有植物都减少了曼塔格霉的幼苗出苗，生长和存活。混合物之间在抑制效果方面有很大差异。影响的性质取决于物种的组成，一种混合​​物在防止定殖方面更有效，另一种则基本上影响幼苗的生长和存活。不论种子混合物如何，总的植物覆盖率似乎对曼氏根瘤菌有重要影响。其他可能起作用的因素包括种子植物的凋落物和加拿大菊科植物（加拿大一枝黄花）的化感作用。我们的研究为促进恢复植物覆盖率提供了越来越多的证据，作为防止控制操作后入侵物种再侵染的一种手段。