Pollination provided by bees is a critical ecosystem service for agricultural production. However, bee populations are at risk from stressors such as habitat loss, pesticides, and disease. On-farm wildflower plantings is one mitigation strategy to provide habitat and resources for bees. In many instances, government programs can subsidize the installation of these plantings for private landowners. Semi-natural habitat (SNH) in the landscape is also important for bee conservation and may alter the effectiveness of wildflower plantings. In this study, we tested the effectiveness of wildflower plantings and interactions with SNH in the landscape for promoting bee abundance and richness. Bee surveys were conducted over 2 yr at 22 sites in eastern Virginia and Maryland. Wildflower plantings, averaging 0.22 ha in size, were installed and maintained by cooperators at 10 of the sites. In total, 5,122 bees were identified from 85 species. Wildflower plantings did not alter bee communities independently, but bee abundance was greater on farms with plantings and 20–30% SNH in the landscape. Bee abundance and richness had nonlinear responses to increasing SNH in the landscape. The positive effects for richness and abundance peaked when SNH was approximately 40% of the landscape. Similar to predictions of the intermediate-landscape complexity hypothesis, increases in bee abundance at wildflower sites were only detected in simplified landscapes. Results indicate that small wildflower plantings in the Mid-Atlantic U.S. only provided conservation benefits to bee communities under specific circumstances on the scale studied, and that conserving SNH across the landscape may be a more important strategy.

中文翻译：

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景观背景影响野花植物的蜜蜂保护价值

蜜蜂提供的授粉是农业生产的重要生态系统服务。然而，蜜蜂种群面临栖息地丧失、杀虫剂和疾病等压力源的风险。农场野花种植是为蜜蜂提供栖息地和资源的一种缓解策略。在许多情况下，政府计划可以补贴私人土地所有者安装这些植物。景观中的半自然栖息地 (SNH) 对于蜜蜂保护也很重要，并且可能会改变野花种植的有效性。在这项研究中，我们测试了野花种植的有效性以及景观中与 SNH 的相互作用，以促进蜜蜂的丰度和丰富度。在弗吉尼亚州东部和马里兰州的 22 个地点进行了 2 年多的蜜蜂调查。野花种植面积平均为 0.22 公顷，由合作者在其中的 10 个站点安装和维护。总共从 85 个物种中鉴定出 5,122 只蜜蜂。野花种植并没有独立地改变蜜蜂群落，但在种植园和景观中 20-30% SNH 的农场中，蜜蜂的丰度更高。蜜蜂丰度和丰富度对景观中 SNH 的增加具有非线性响应。当 SNH 约占景观的 40% 时，对丰富度和丰度的积极影响达到顶峰。与中等景观复杂性假说的预测类似，野花地点蜜蜂丰度的增加仅在简化的景观中检测到。结果表明，美国中大西洋地区的小型野花种植仅在研究规模的特​​定情况下为蜜蜂群落提供了保护效益，