Abstract Local mass occurrences of Tansy ragwort (Jacobaea vulgaris, Asteraceae), a native plant usually sparsely interspersed within extensive grassland, have been suggested to cause health hazards for livestock and humans. While current management options, particularly herbicide application and mechanical eradication, undermine conservation targets of extensive grasslands, sown wildflowers are a popular agri-environment scheme that may reduce pollinator visitation on J. vulgaris and thus, mitigate the plant’s dominance. Hence, with this study we aimed to explore whether the availability of sown wildflower patches reduces pollinator visitation rates on J. vulgaris in species-rich and species-poor grassland, respectively, and whether patterns depend on wildflower cover. To do so, we monitored pollinator visitation rates on J. vulgaris when wildflower fields were available to flower visitors or temporarily covered by mesh nets in a field experiment. The availability of wildflower patches significantly reduced visitation rates of honeybees, bumblebees, solitary bees and hoverflies on J. vulgaris, while increasing wildflower cover promoted this effect for J. vulgaris in species-poor grassland. Moreover, species-specific flower preferences and seasonal shifts in the quantitative availability of wildflower species determined the efficacy of wildflower patches. To conclude, our findings suggest sown wildflower fields as an alternative management option to mitigate the dominance of J. vulgaris in plant-pollinator networks given that wildflower mixtures are tailored to species-specific requirements of flower visitors. Future research, however, should explore whether wildflower fields ultimately mitigate the negative consequences associated with the local mass occurrences of J. vulgaris without undermining conservation targets on extensive grassland.

中文翻译：

---

播种野花田是减少蜜蜂和其他传粉昆虫对普通雅科布的访问率的有效措施

摘要 艾菊 (Jacobaea vulgaris, Asteraceae) 是一种本地植物，通常稀疏散布在广阔的草原中，已被认为会对牲畜和人类的健康造成危害。虽然目前的管理选择，特别是除草剂的应用和机械根除，破坏了大面积草原的保护目标，但种植野花是一种流行的农业环境计划，它可能会减少对普通野花的传粉媒介的访问，从而减轻植物的主导地位。因此，通过这项研究，我们的目的是探索播种的野花斑块的可用性是否分别降低了在物种丰富和物种贫乏的草地上对普通野花的传粉者访问率，以及模式是否取决于野花覆盖。为此，我们监测了 J. 的传粉媒介访问率。当野花田可供花卉游客使用或在田间试验中暂时被网状网覆盖时，普通植物。野花斑块的可用性显着降低了蜜蜂、大黄蜂、独蜂和食蚜蝇对普通蜂的访问率，而增加野花覆盖率在物种贫乏的草地上促进了普通蜂的这种效应。此外，特定物种的花卉偏好和野花物种数量可用性的季节性变化决定了野花斑块的功效。总而言之，我们的研究结果表明，鉴于野花混合物是根据花卉游客的物种特定要求量身定制的，因此种植野花田可作为一种替代管理选择，以减轻普通野花在植物 - 传粉媒介网络中的主导地位。然而，未来的研究，