Bees are declining, which is worrisome since they both have intrinsic conservation value and play a major role as pollinators in both natural and managed ecosystems. Land use change and lack of suitable habitats are often suggested as driving forces of bee decline. To propose mitigation measures to halt bee decline, it is important to understand how land use relates to bee abundance and diversity, and to explore consequences for their provision of pollination services. White clover, , is an outcrossing mass-flowering crop, which could serve as an abundant, although ephemeral, food resource for bees. We investigated how the bee community in 39 fields of white clover grown for seed, related to local field management (organic, conventional without insecticides and conventional with insecticides) and landscape context (proportion semi-natural land), and how this pollinator community related to white clover seed set. The honey bee, , was the most commonly observed bee species, and two generalist bumble bee species, and , were the subsequently most common. We observed fewer non- bees, and a lower bee species richness in organic white clover seed fields compared to conventional fields independent of insecticide treatment. Bee species richness in both conventional and organic fields were positively related to the proportion of semi-natural land in the landscape, likely because of a larger species pool in such landscapes. Initial seed set in immature inflorescences was positively related to bee abundance, whereas final seed set in mature inflorescences was unrelated to bee abundance, possibly as a consequence of seed-eating weevils consuming a large proportion of the seeds. We conclude that both bee visitation and seed set in white clover benefit from conventional management and that landscapes rich in semi-natural habitats will make future crop production more resilient. The observed positive relationship between bee abundance and initial seed set suggests that if we can mitigate pest impacts and increase bee abundance in clover seed fields, the final seed yield can be increased. Thus, bee decline should be considered and mitigated both to maintain biodiversity in general and for crop seed production specifically.

中文翻译：

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白三叶草传粉者和种子与当地管理和景观环境的关系

蜜蜂正在减少，这是令人担忧的，因为它们既具有内在的保护价值，又在自然和管理的生态系统中作为传粉媒介发挥着重要作用。土地利用变化和缺乏合适的栖息地通常被认为是蜜蜂数量下降的驱动力。为了提出阻止蜜蜂衰退的缓解措施，重要的是要了解土地利用与蜜蜂丰度和多样性的关系，并探讨其提供授粉服务的后果。白三叶草是一种异型杂交的大量开花作物，可以作为蜜蜂丰富但短暂的食物资源。我们调查了 39 个白三叶草种子田地中的蜜蜂群落与当地田间管理（有机、常规不使用杀虫剂和常规使用杀虫剂）和景观环境（半自然土地比例）之间的关系，以及该传粉昆虫群落如何与白三叶草种子集。蜜蜂 是最常见的蜜蜂物种，而两种通才熊蜂物种 和 是随后最常见的蜜蜂物种。与不受杀虫剂处理的传统田地相比，我们观察到有机白三叶草种子田中的非蜜蜂较少，蜜蜂物种丰富度较低。常规田地和有机田地中的蜜蜂物种丰富度与景观中半自然土地的比例呈正相关，可能是因为此类景观中的物种库较大。未成熟花序中的初始结籽与蜜蜂丰度呈正相关，而成熟花序中的最终结籽与蜜蜂丰度无关，可能是食籽象鼻虫消耗掉大部分种子的结果。我们的结论是，蜜蜂的造访和白三叶草的结籽都受益于常规管理，而丰富的半自然栖息地景观将使未来的作物生产更具弹性。观察到的蜜蜂丰度与初始种子结实率之间的正相关关系表明，如果我们能够减轻害虫影响并增加三叶草种子田中的蜜蜂丰度，则可以增加最终种子产量。因此，应考虑并减轻蜜蜂的减少，以维持总体生物多样性和具体作物种子生产。